Glossary extracted starting with automatic seeds, with BOW for the domain phy and language EN

upsilon particle	(a) A very massive (9 GeV) meson built from a bottom quark and bottom antiquark
zenith	The point directly above an observer on the celestial sphere, so that a line to it is at right angles to the plane of the horizon.
green flash	An optical phenomenon visible for a short time as a green spot in the sky just after sunset or before sunrise.
marian flag	One of a number of flags – most often a bicolour of blue and white - that symbolizes veneration of the Virgin Mary in the Christian tradition (see also ‘Christian flag 1)' and ‘religious flag').
electromagnetic force	A fundamental force that governs all interactions among electrical charges and magnetism
entropy	Measure of the disorder of a system.
reticulum	reticular (net-like) pattern
solstice	when the Sun appears furthest north or south of the celestial equator
eddington-lemaître universe	A cosmological model in which the cosmological constant plays a crucial role by allowing an initial phase that is identical to the Einstein static Universe
altazimuth mount	A type of telescope mount that is simpler to construct than an equatorial mount, but requires simultaneous movement about the vertical (altitude) and horizontal (azimuth) axes to track a celestial object.
inversion	The term used with CCDs to indicate that the applied voltage has not only driven away the majority carriers but has actually attracted the minority carriers of the opposite sign
juno	The queen of the gods
abundance ratio	The ratio of the number of atoms of an isotope to the number of atoms of another isotope of the same element in a sample
angular diameter	The arc angle across an object.
higgs particle	The particle or particles associated with the bundles of energy in the Higgs field
raven flag	The flag considered by some sources to have been carried by Viking raiding parties up until the 11th Century, and to have been carried by the Normans at the Battle of Hastings (1066) (see also ‘Bayeux tapestry').
autumnal equinox	the point on the celestial sphere where the sun crosses the celestial equator from north to south
high-energy physics	See particle physics
feminine signs	The Earth and Water signs
lyman series	(a) A series of lines in the ultraviolet spectrum emitted by excited hydrogen atoms
sidereal day	because Earth orbits the Sun and during one full rotation of Earth itself, it has moved its position with respect to the Sun.
wave height	The vertical distance between crest and trough.
solstice	The time of the year when the Sun appears furthest north or south of the celestial equator
solar cycle	The 11-year period between maxima (or minima) of solar activity
eccentricity	a parameter that describes the shape of an orbit; the closer the eccentricity is to zero, the more circular the orbit
prare	Precise Range and Range-rate Equipment
shadow matter	Theoretical classes of particles, their existence intimated by supersymmetry, theory, that participate in few if any of the four known fundamental forces
anti-proton	The antiparticle of a proton, identical in mass and spin but of opposite (negative) charge
aperture	The diameter of a telescope's main lens, mirror or collecting dish.
anthropic principle	The idea that certain characteristics of the physical universe are carefully tuned to allow the existence of carbon-based lifeforms.
faceted	The term which may be used to describe a charge (such as a star or sun) that is given a three-dimensional appearance by the use of contrasting colours or of simple construction lines - sectored or a star gyronny (see also ‘caltrap', ‘counterchanged’, ‘cross gyronny’ in ‘appendix VIII’, ‘sector(s) 1)’ and ‘sectored 2)’).
prospect	A person who has shown interest in qualifying for Mensa membership
angles	The lines of the chart wheel which lie at 0 degrees (Ascendent), 90 degrees (I.C.), 180 degrees (Descendent), and 270 degrees (M.C.)
nodes	Points where an orbit crosses a plane.
coordinator	A loose term for a volunteer who does anything from acting as a media contact to organizing and hosting functions.
taloned	See ‘armed’ (also ‘membered’).
visible spectrum	The small range of the electromagnetic spectrum that human eyes percieve as light
parallax	An angular shift in apparent position due to an observer's motion; more specifically, a small angular shift in a star's apparent position due to the Earth's motion around the Sun
admiral's flag	See ‘flag of command 1)'.
sagittarius b2	A massive (3 × 106 M), dense (up to 108 particles per cm3) H II region and molecular cloud complex - the richest molecular source in the Galaxy
bi-quintile	A minor benefic aspect, separating distance 144°, based on the fifth harmonic (multiples of 72°, a quintile, which is 1/5 of 360°).
quarter the arms	(v) The heraldic phrase used when a shield or banner of arms, which was formerly impaled, is divided into four, with the previously impaled arms displayed in opposing quarters – see ‘impaled' and compare with ‘quartered 1)'.
reciprocal linear dispersion	The inverse of the linear dispersion of a spectrometer which is the rate of change of position along the spectrum (in millimeters) with wavelength (in angstroms)
terbium	Symbol:"Tb" Atomic Number:"65" Atomic Mass: 158.93amu
member at large	The person (or persons) who have a vote on matters brought before the ExCom, and does other duties as directed.
anorthosite	The predominant rock of the lunar highlands.
coudé focus	(a) A focus used primarily for spectroscopy
kamon	See ‘mon 2)’.
mantissa	The decimal part of a common logarithm
radiative transfer	The process by which radiation travels through a medium
rapport measurement	From the French, literally related measurement; applied to progressions based on advancing a planet's natal position one degree for each year after birth.
template flag	See ‘archivexillum’.
laser	Light Amplification by Stimulated Emission of Radiation
spiritualism	Belief that material interactions alone cannot account for all phenomena, and that some - e.g., thought - are due to the fundamentally insensible actions of intangibles
charge	The fundamental property of a particle that causes it to be affected by the electromagnetic force
fits	Flexible Image Transport System A method for saving image data which has become standard in astronomy
vertical pennant	1) Generically, any pennant designed to be hung vertically (see also ‘pennant 2)')
mean water level	The average of all hourly water levels over the available period of record.
faculae	bright patches that are visible on the Sun's surface, or photosphere.
nonelectrolyte	This is a solute that cannot conduct electricity when dissolved in the solvent (water)
culmination	An object culminates when it reaches greatest and least altitudes (upper culmination and lower culmination respectively)
geometric position	The geocentric position of an object on the celestial sphere referred to the true equator and equinox, but without the displacement due to planetary aberration
boltzmann factor	The factor e-E / kT involved in the probability for atoms having an excitation energy E at temperature F
aphelion	The point in a body's orbit which is furthest from the Sun.
kari	Korea Aerospace Research Institute - KARI website KARI is a Korean institute dedicated to aerospace research and developing and implementing applications in this field.
rabi frequency	this is the frequency at which atomic population is coherently transferred from one state to another by a resonant radiation field; it is named after its discoverer I
empale	See ‘impale’.
blocking layer	An undoped layer in an extrinsic infrared detector which converts the action of the photoconductor to a behavior more like a photovoltaic detector
luminosity class	(a) A measure of a star's intrinsic brightness, as determined from the star's spectrum
relaxation time	Period required for the reestablishment of thermal equilibrium; in particular (in the astronomical context) the period required for the reestablishment of a random distribution of motion in a cluster of stars
plutonium	Symbol:"Pu" Atomic Number:"94" Atomic Mass: (244)amu
saltirewise	See ‘in saltire’.
propulsion	The act of moving an object and maintaining its motion.
quadrature	Term that describes two celestial bodies appearing to be ninety degrees apart, from the perspective of the observer
ellipse	an ellipse is an oval shape
clapeyron's equation	A fundamental relation between the temperature at which an inter-phase transition occurs, the change in heat content, and the change in volume
cosine law	see Lambert's Law
radium	Symbol:"Ra" Atomic Number:"88" Atomic Mass: 226.03amu
crystal defect	Variation in the regular arrangement of the atoms or molecules of a crystal
period-luminosity relationship	Several classes of pulsating variable stars such as Type I and II Cepheids and RR-Lyrae stars exhibit a period-luminosity relatinship
meridian	an imaginary circle drawn through the North and South poles of the celestial equator.
saint george-type cross	See ‘cross 1)’ (also ‘St George’s Cross 3)’).
geocentric	Refers to the Earth as the center of human experience, therefore becomes the center in the plotting of a chart
ba or barium stars	Late type giants (G2 to K4) with a very strong BaII 4554 line
isoe	Integrated Sequence of Events.
magnetic mirror	Phenomenon that transfers energy related to movement that is parallel to the field lines into energy related to perpendicular movement; as a result, the particles slow down, stop and then reverse when they enter the zones where the field lines close in.
eruptive variable	see Cataclysmic Variable
solar	System formation
bps states	Configurations in a supersymmetric theory whose properties can be determined exactly by arguments rooted in symmetry
main ordinaries	See ‘ordinary’.
kelvin	a temperature scale used in sciences such as astronomy to measure extremely cold temperatures
ionization	the process by which ions are produced, typically occurring by collisions with atoms or electrons ("collisional ionization"), or by interaction with electromagnetic radiation ("photoionization").
absolute zero	This is the coldest temperature theoretically possible (-273.15 degrees Celsius), where the motion of atoms in a material would stop completely, leaving them only with a small amount of quantum mechanically energy.
footpoint	the intersection of magnetic loops with the photosphere.
relativistic quantum field theory	Quantum-mechanical theory of fields, such as the electromagnetic field, that incorporates special relativity
ram pressure	Motion of a blunt body at supersonic velocity through an ambient gaseous medium causes a strong drag or ram pressure to be exerted on the body
meitnerium	Symbol:"Mt" Atomic Number:"109" Atomic Mass: (266)amu
susceptibility	Symbol: X The ratio, for a given substance, of the magnetization of a sample to the magnetic field strength applied
qualities	Cardinal, Fixed, Mutable.
binning	On-chip binning
serpentis	A G0 V star almost identical to the Sun in its energy distribution
geronny	See ‘gyronny’.
hydrogen	Symbol:"H" Atomic Number:"1" Atomic Mass: 1.01amu
elements	Four-fold division of the Zodiac: Fire, Earth, Air, Water
facula	Unusually bright spots, or patches, on the Sun's surface
nova	A star that flares up to several times its original brightness for some time before returning to its original state.
renormalization	(a) The mathematical process which ensures that the basic quantities in quantum field theory (e.g
covariant function	Essentially the same as the correlation function
21 march	At this time, the length of daylight is 12 hours and the Sun reaches a noonday altitude of 38.5°
mentally	The official newsletter of Tallahassee Area Mensa.
distance indicator	Any property of a star or galaxy that can be used to measure distance; usually involves a local calibrator whose distance is known via a different technique.
critical speed	In fluid flow, the speed at which the behavior of the fluid switches from that of laminar flow to that of turbulent flow or vice versa
cantonal flag	The sub-national flag of a territorial division within a country, particularly if that subdivision is is called a canton - e.g
fos	Flight Operation Segment, composed of the Flight Operations Control Centre located at ESOC, Darmstadt and the associated command and control stations
ncep	National Center for Environmental Prediction
call sign hoist	A hoist of signal flags displaying the international call sign of a civil or naval vessel – but see ‘make her number' (also 'address group', 'call sign', ‘signal hoist', ‘international code of signal flags’, ‘pendant number’ and ‘signal flag’).
macho	an acronym for "Massive Compact Halo Object" - supposed dark, massive objects surrounding our galaxy
strange attractor	(a) A path in phase space that is not closed
program chair	The person responsible for arranging, setting up, and planning programs
euler number	A number used in fluid dynamics defined by p / v2, where p is pressure, density and v velocity
cdm	Cold Dark Matter
solar wind	The constant flow of charged particles from the Sun, extending throughout the solar system.
imperial arms	The arms that represent an empire and its ruler - a type now entirely obsolete - but see ‘imperial emblem' (also ‘imperial standard(s) 1)' and ‘royal arms').
apogalacticon	The point in a star's orbit farthest from the Galactic center
impact crater	A roughly circular depression of any size (known examples range from microscopic size to diameters greater than 1000 km) caused by a meteorite impact.
trigonometric parallax	Nearby celestial objects exhibiti a perioidic shift in position relative to background stars due to the earth's motion around the Sun
achondrite	A stone meteorite that contains no chondrules.
self-absorption	Reduction in relative intensity in the central portion of spectral lines resulting from selective absorption by a cooler shell surrounding the hot source
embroider	(v) The use of needlework to create or enhance a design - employed especially on military colours and flags for indoor display (see also 'colour 2)', 'colours 2)’, ‘indoor flag’ and ‘raised detail').
zenith	Point directly above your head in the night sky.
position of equilibrium	This measurement is the point in a chemical reaction where the forward reaction rate equals the reverse reaction rate.
radarsat	RADAR Satellite - RADARSAT-2 website RADARSAT is a joint CSA/MDA mission consisting of two Earth observation satellites
spinor	A mathematical object that reverses sign after a rotation by 360 degrees and returns to itself only after a rotation by 720 degrees
barsoom	The local name for Mars in Edgar Rice Burroughs' SF books.
meridian	An imaginary line in the sky that runs form the direction of the South Pole, through the zenith, to the direction of the North Pole
meridian	An imaginary circle drawn through the North and South poles of the celestial equator.
lens	A see-through object, usually made of glass, that can bend light.
super-high frequency	SFH A radio frequency in the range between 30 GHz and 3 GHz (wavelength 1-10 cm)
patera	A shallow crater with a complex, scalloped edge.
cavus	Hollow, irregular depression.
dark matter	"Missing" mass in the Universe that cannot be seen, but is detected through the movement of stars and galaxies
quinas	The Portuguese term for the five plates or discs with which the five blue escutcheons on the national arms of Portugal are charged (see also ‘disc' and ‘plates').
accelerator	(a) A machine for speeding subatomic particles to high velocity, then colliding them with a stationary target or with another beam of particles moving in the opposite direction
bolometer	(a) An instrument for measuring small amounts of radiant heat or microwaves
gardamano	See ‘handguard’.
color force	The force between two particles carrying color charge
finder	A small, wide-field telescope attached to a larger telescope
h ii	Ionized hydrogen - that is, hydrogen with its electron missing
isoplanatic patch	The angular region on the sky over which the wavefront correction applied by an adaptive optics system remains valid
hyperdimensional	Involving more than the customary four dimensions (three of space plus one of time) of relativistic space-time
epitaxial	A thin layer of differently doped semiconductor used in the construction of solid-state devices such as the CCD
silver	Symbol:"Ag" Atomic Number:"47" Atomic Mass: 107.87amu
low pressure systems	CONDENSATION
cosmic year	Time the Sun takes to "orbit" in galactic rotation: about 225 million years
gravitational equilibrium	The condition in a star in which at each point the weight of the overlying layers is balanced by the total pressure
metar	BLOWING SPRAY
photographic meteor detection	The capture of meteors on photographic film
escape velocity	speed a body needs to travel in order to escape the surface gravity of a star or planet
ferrule	A metal tip placed on the bottom of a staff (see also ‘pike’ and ‘staff 2)’).
lte	Local Thermodynamic Equilibrium -- The assumption that all distribution functions characterizing the material and its interaction with the radiation field at a point in the star are given by thermodynamic equilibrium relations at local values of the temperature and density
three-phase ccd	A CCD construction in which three overlapping metal electrodes are used to define a pixel and effect the transfer of charge, in either direction along a column, by the charge-coupling method
semisquare	Minor Aspect in which the planets are approximately one and a half signs apart, or 45 degrees
alpha centauri	(1) The nearest star system, composed of three members; (2) the brightest of these three.
chandler period	The period of the variation of the celestial poles (about 416-433 days, with a peak at 428 days)
constant of precession	see Precession of the Equinoxes
ao cassiopeiae	A binary in which the larger, less massive, hot primary is highly distorted, and in which rapid mass exchange is occurring
azimuth	Angular position on the celestial sphere along the horizon as measured counterclockwise from the north.
epoch	(a) A point of time selected as a fixed reference
great circle	An imaginary circle on the surface of a sphere whose center is at the center of the sphere.
weak-line stars	Late type objects in which the lines of all metals are weakened when compared with normal stars of the same temperature
zenith	This is the point in the sky directly above the observer
declination	A component of the coordinate system used to designate positions on the celestial sphere
matter fields	the fields whose quanta describe the elementary particles making up the material content of the Universe (as opposed to the gravitons and their supersymmetric partners).[D89]
cation	A positively charged ion, formed by removal of electrons from atoms or molecules
ball of difference	In British Royal Navy usage and some others, the disc or discs of distinction carried by the command flags of those flag officers who rank below the grade of full admiral (see also ‘boat flag 3)’, ‘disc’, ‘flag of command 1)’, ‘flag officer 1)’ and ‘flag officer 2)’.
wavefront error	The departure of the true wavefront in an electromagnetic wave propagating through an optical system from the ideal spherical wave at that point
catadioptric lens	A compound lens in which both a mirror(s) and lenses are used to form an image
lupus loop	A radio source, a large broken shell 4°.5 in diameter, identified as a prehistoric supernova remnant
cosmic background radiation	The nearly uniform radiation received from all regions of the sky
main-sequence turn-off	The point on the HR diagram of a star cluster where main-sequence stars are beginning to leave the main sequence
autumnal equinox	see Equinoxes [A84]
disjunct	Another name for the quincunx aspect
relativity	(see general relativity and special relativity)
gravitational perturbation	A small deviation to an orbit that can lead to a very different eventual position.
solstice	is defined as the time of year when the declination of the sun reaches a minimum or maximum value
m104	The Sombrero galaxy, in which galactic rotation was first detected
mascons	Abbreviated form of mass concentrations: apparent regions on the lunar surface where gravity is somehow stronger
convection	SUBTROPICAL
albedo	A measure of the reflectivity of an object and is expressed as the ratio of the amount of light reflected by an object to that of the amount of light incident upon it
surface temperature	(see effective temperature)
autumnal equinox	The intersection of the ecliptic and celestial equator where the Sun crosses the equator moving from north to south
hassium	Symbol:"Hs" Atomic Number:"108" Atomic Mass: (265)amu
lamb shift	(a) A minute correction to the energy levels of atoms (specifically the first excited state of the hydrogen atom) predicted by quantum electrodynamics, and confirmed to great accuracy by Willis Lamb
differentiated	when a (partially) molten body has been divided into two or more fractions of dissimilar compositions
length	The fundamental measure of size or distance, represented by units of meters in the metric system.
equinox	Literally "equal night"
mct	Mission Control Team, Section 391 project operations.
infrared photometry	The measurement of light intensities using infrared light instead of optical (visible to the human eye) light
hemisphere	Half of a sphere
equilibrium expressions	The expression giving the ratio between the products and reactants
filtrate	Filtrate is the solid substance remaining after you remove the liquid of a solution
line spectrum	(a) A spectrum composed of a number of discrete lines corresponding to single wavelengths of emitted or absorbed radiation
ionosphere	THICKNESS
saturation horizon	The saturation horizon of calcium carbonate is the transition depth between the supersaturated upper ocean and the undersaturated deep ocean
big blue bump	The flux densities of most Seyfert 1 galaxy and quasar continua have an average slope of -1 (i.e
time dilation	The idea that as you approach the speed of light time slows down and mass increases.
cn-strong stars	Late type giants with strong CN bands
air	SATURATION POINT
national	National level of American Mensa governance and administration
dexter	The heraldic term for the right hand side of a flag or shield from the point of view of the bearer, or the left hand side from the point of view of an observer (see also ‘sinister’).
quantum electronics	this is the name used for those parts of quantum optics which have practical device applications.[D89]
lacus	lake
free parameter	A number which is needed to define a theory well enough so that predictions can be made, but which must be determined by experiment or observation
sit	Silicon Intensified Target [LLM96]
astrometry	The aim of Gaia is to perform three-dimensional mapping of the stars in our Galaxy
semi-major axis	The semi-major axis of an ellipse (e.g
lagrange point	french mathematician and astronomer Joseph Louis Lagrange showed that three bodies can lie at the apexes of an equilateral triangle which rotates in its plane
http	Hyper-Text Transfer Protocol.
db	Decibel, an expression of ratio (usually that of power levels) in the form of log base 10
ethernet	A system for linking computers with a single serial cable
heliocentric	Measurements based upon the Sun as the central point of reference or observation; Sun-centered.
dentelé	See ‘dancetty’ (also ‘serrated’).
ruminant signs	an obsolete term applied to signs symbolized by cud-chewing animals, namely, Aries (ram), Taurus (bull), and Capricorn (goat).
atmosphere	= 1.013 bars = 1.03 kg/cm^2 = 14.7 pounds per square inch, standard atmospheric pressure at sea level on Earth.
uranium	Symbol:"U" Atomic Number:"92" Atomic Mass: 238.03amu
regolith	The layer of fragmentary debris produced by meteoritic impact on the surface of the Moon or a planet
tide staff	A tide gauge consisting of a vertical graduated pole from which the height of tide at any time can be read directly
rocard scattering	Linearly anisotropic scattering
mass	Meridian An imaginary circle drawn through the North and South poles of the celestial equator.
quantum mechanics	The branch of physics dealing with the structure and behavior of atoms and their interaction with light.
chondrite	Stony meteorite containing chondrules, believed to be little altered since their formation 4.6 billion years ago.
zenith	The point on the celestial sphere directly overhead.
light curve	A plot showing the variations in the brightness of an object with time
action	A quantity related to the momentum and position of a body or system of particles
quadrature	A point in the orbit of a superior planet where it appears at right angles to the Sun as seem from Earth.
coordinate covalent bond	Interatomic attraction resulting from the sharing of a lone pair of electrons from one atom with another atom
gironné	See ‘gyronny’.
faculae	Bright patches that are visible on the surface of the Sun (also known as the photosphere).
constellation	A grouping of stars in the sky, generally representing a region from 1-15 degrees in the sky associated with a figure drawn using the brightest stars as vertices
electron flux	the rate of flow of electrons through a reference surface
adaptive optics	A method of correcting for atmospheric interference using a bright reference star to detect variations and a deformable mirror to correct for them
c galaxies	In the Yerkes 1974 system, small, high surface-brightness galaxies which are slightly resolved on medium- and large-scale photographs
sesquiquintile see	tredecile.
white dwarf	stars in binary systems that blow off material accumulated from the binary companion
love number	A measure of the rotational deformation of a rotating body in hydrostatic equilibrium
climate	The average weather conditions of a place or area over a period of years.
receiver	General term for a radio detection system
anode	The electrode where electrons are lost (oxidized) in redox reactions.
node	point in which the orbit of a body intersects the
channel stops	Narrow, heavily doped strips in a silicon CCD which act like walls to prevent sideways movement of charge in a pixel
bose-einstein statistics	The statistical rules for studying systems of identical bosons
tantalum	Symbol:"Ta" Atomic Number:"73" Atomic Mass: 180.95amu
transition region	Low solar corona characterized by a sudden increase in temperature (from a few thousand to a few million degrees).
aphelion	the point along a planetary orbit that is farthest from the Sun;
millibar	a measure of atmospheric pressure equal to 1/1000 of a bar
equivalent width	A measure of the total amount of energy subtracted from the continuous spectrum by an absorption line on a graph of relative intensity versus wavelength
giga-	A prefix meaning 109
perigee	That orbital point nearest the Earth when the Earth is the center of attraction, as opposed to apogee.
bismuth	Symbol:"Bi" Atomic Number:"83" Atomic Mass: 208.98amu
cosmic microwave background	In 1992, COBE detected for the first time minute variations of temperature (the anisotropies) in the cosmic microwave background.
excitation potential	Amount of energy required to bring an electron from its ground state to a given excited state (measured in electron volts)
proper motion	The angular rate of motion of a star or other object across the sky
chaos	A field of study modeling systems in nature that can be described in Newtonian terms but whose futures are, for all practical purposes, unpredicatable; e.g., the turbulent flow of water or the beating of a human heart.
sco	see Antares
hercules cluster	An unsymmetrical cluster of about 75 bright galaxies (z = 0.036) of which about half are spiral or irregular and about half elliptical or 50
greenwich sidereal day number	The integral part of the Greenwich sidereal date
restoration	A process used by radio astronomers to eliminate the smoothing effect observed in radio maps that is caused by the finite width of the telescope beam
bn object	Becklin-Neugebauer Object One of the first major discoveries of infrared astronomy
artificial birthday	See adjusted calculation date.
blazed grating	Diffraction grating so ruled that the reflected light is concentrated into only a few orders, or even a single order, of the spectrum
libration zone	Regions of the Moon occasionally visible due to the Moon's apparent periodic wobble.
mean motion	Average motion or rate of travel within a specified time period.
admiralty warrant	See ‘warrant' and its following note.
virtual interaction	Quantum uncertainties in energy make it possible for virtual particles to be constantly created and annihilated during elementary particle interactions
thermodynamic potential	a function of the state of a system which takes its extreme value on the asymptotically stable state reached by the system in the course of time
higgs boson	(a) A hypothetical, spinless particle that plays an important role in the Glashow-Weinberg-Salam electroweak theory (and in other theories involving spontaneous symmetry breaking, e.g
master equation	an equation describing the evolution of the probability of a state at a given time as the balance between transitions leading to this state, and transitions removing the system from this state
many-body problem	The difficulty of calculating the interactions - e.g., the newtonian gravitational interactions - of three or more objects
selenium	Symbol:"Se" Atomic Number:"34" Atomic Mass: 78.96amu
ratio	See ‘proportions’.
attenuation factor	In a rocket-borne or satellite-borne telescope, the ratio of the expected counting rate to the observed counting rate
open string	A type of string with two free ends
lame degrees	See mutilated degrees.
rectification	The correcting of an inexact birthtime or the determining of an unknown birthtime through astrological methods.
azimuth	the angular distance of an object around or parallel to the horizon from a predefined zero point
radiation belt	a ring-shaped region around a planet in which electrically charged particles (usually electrons and protons) are trapped
radius	The straight line from the centre of a sphere or circle to any point on its surface.
vacancy	A site on a lattice on which there is no atom present
zenith	The point on the celestial sphere directly above the observer
chemical element	A chemical that cannot be broken down into more basic chemicals.
hyperbola	A hyperbola is a conic section (the intersection of a cone with a plane) that has two mirror-image branches
surface channel	A semiconductor device construction in which the electron charges are held or moved near the surface of the silicon crystal
krypton	Symbol:"Kr" Atomic Number:"36" Atomic Mass: 83.80amu
carina	(a) A constellation in the southern sky and home of the bright star Canopus
rift valley	an elongated valley formed by the depression of a block of the planet's crust between two faults or groups of faults of approximately parallel strike
malmquist bias	The systematic distortion in a standard candle's effective range due to failure in detecting the fainter examples of the standard candle at large distances
yod	An aspect configuration in which two planets in sextile both form a quincunx (inconjunct) with the same third planet; it is given a karmic connotation
m51	The Whirlpool Galaxy, a stunning spiral in the constellation canes venatici
hydrologic cycle	The Hydrologic Cycle (also known as the water cycle) is the journey water takes as it circulates from the Earth to the sky and back again.
susy	A common abbreviation for Supersymmetry [K2000]
star cluster	A large grouping of stars, from a few dozen to a few hundred thousand, that are bound together by their mutual gravitational attraction.
slow nova	A nova whose light curve shows a much more gradual development - i.e., rise time of several days, maximum of several weeks, slower decline, amplitude only about 10 mag
ionized	(a) Having lost one or more electrons from an atom
breccia	A rock made from mineral fragments cemented together by the heat of meteoroid impact.
earth	's equator onto the sky
zenith	a point directly overhead from an observer.
crystallization	Physical or chemical process or action that results in the formation of regularly-shaped, -sized, and -patterned solid forms known as crystals.
stilb	1 stilb = 1 candela per square centimeter
joinant	See ‘conjoined’.
snu	Solar Neutrino Unit [LLM96]
upright triangle	See ‘triangle’.
gauge group	the mathematical group associated with a particular set of gauge transformations
electromagnetic radiation	PILOT BALLOON
universality	The phenomenon whereby many microscopically quite different physical systems exhibit critical point behavior in with quantitatively identical features such as critical indices
empirical	Derived from observation or experiment.
white dwarf	The 'remains' of a star after it has collapsed
radiation zone	The inner region of the solar interior.
inverse square law	A law describing the weakening of a force or energy flow with distance from the source as 1/R2.
electron affinity	(a) The work needed to remove an electron from a negative ion and move it to infinity
sublimation	The process of a solid returning directly to a gas without changing to a liquid first.
static universe	A Universe whose radius of curvature is constant and independent of time, as in the Einstein Universe
cross-section	The area formed by a plane cutting through an object.
cherenkov detector	Apparatus through which it is possible to observe the existence and velocity of high-speed particles important in experimental nuclear physics and in the study of cosmic radiation
asteroid belt	Their Earth-approaching orbits are the result of collisions with other asteroids or the gravitational influence of Jupiter
gardant	See ‘guardant’ in ‘Appendix V’.
snr	Signal-to-Noise Ratio.
plato	Greek 429-355 B.C., studied in Egypt and elsewhere, pupil of Socrates, fellow student of Euclid, follower of Pythagoras
ridge	TSUNAMI
ascendant	The degree of the zodiac rising over the eastern horizon of the birthplace at the moment of birth
super radiance	A process by which energy may be extracted from a rotating black hole
dense	A compact substance or a substance with a high density.
meteor shower	A regular (typically annual) event in which the orbit of Earth intersects that of a meteoroid stream, causing a number of meteors with approximately parallel trajectories which appear to emanate from the same radiant.
space	Traditionally the three-dimensional theater within which events transpire, explicable by means of Euclidean geometry
apoapsis	the point in orbit farthest from the planet.
focal length	The distance between a telescope's primary lens or mirror and the point at which an image is brought into focus.
sph	Secondary Product Header.
cartwheel galaxy	A ring-shaped galaxy in the constellation of Sculptor, at a distance of 500 million light years away
relativistic particles	Particles whose velocities approach the speed of light
pyroclastic	pertaining to clastic (broken and fragmented) rock material formed by volcanic explosion or aerial expulsion from a volcanic vent.
cantonal triangle	The newly introduced term for a right-angled, triangular panel set with its legs (or catheti) along the hoist and upper edge of a flag as illustrated below – but see ‘triangular panel 1)’.
ellipse	the oval, closed path followed by a celestial object moving under gravity (e.g
parallax	A system of measuring distances to stars
metar	BLOWING SNOW
deepening	FIREWHIRL
solar wind	A thin flow of energetic and gas charged particles that stream from the Sun
climatological	The climatological value of a variable is its mean over a reference period (generally 30 years)
gauge symmetry	(a) Abstract mathematical symmetry of a field related to the freedom to re-gauge, or re-scale, certain quantities in the theory (potentials) without affecting the values of the observable field quantities
elevations	SNOW PELLETS
amesd	African Monitoring of the Environment for Sustainable Development
solstice	the time of year when the Sun is at the most northern or southern point of the ecliptic
panel	The area of a flag that is surrounded by a border, the panel itself is generally (but not exclusively) used to display charges or other designs (see also ’border’, ‘charge’ and ‘pierced 1)’).
focal ratio	The ratio of the focal length (F) of a mirror or lens to its diameter (D) expressed as a number; f/# = F/D
granules	Convective cells (about 1000 km in diameter) in the solar photosphere
spark spectra	The spectra of ions often produced by a spark discharge (cf
topologically distinct	Two shapes that cannot be deformed into one another without tearing their structure in some manner
corrector plates	Thin lens-like optical pieces which remove certain optical aberrations
optical chaos	in many nonlinear optical systems the output response varies in an unpredictable and uncontrollable fashion despite being governed by deterministic laws
ion	An atom with one or more electrons removed (or added), giving the atom a positive (or negative) charge.
monopole	A hypothetical quantum object being a single, isolated magnetic pole
thermometers	FAIR
imaginary time	time measured using imaginary numbers (i.e
light year	or 3.1 x 1016 metre (see scientific notation)
brans-dicke theory	(a) Alternative theory of gravity to general relativity devised by Carl H
electromagnetic gauge symmetry	Gauge symmetry underlying quantum electrodynamics
hades	An unofficial name for Jupiter IX, the outermost satellite of Jupiter (P = 758 days retrograde, i = 156°, e = 0.28)
weak force	One of the four fundamental forces, best known for mediating radioactive decay
catalyst	Substance that speeds up a chemical process without actually changing the products of reaction.
midpoints	The midpoint between two planets or angles and sometimes house cusps.
msis	Mass-Spectrometer-Incoherent-Scatter model, or international model of the high terrestrial atmosphere
mass absorption coefficient	A measure of the fraction of radiation absorbed at a certain wavelength per unit mass
cygnus a	A double radio source, the third strongest radio source in the sky (after the Sun and Cas A), at one time believed to be caused by the collision of two galaxies
electron volt	Abbreviated eV
winding number	The number of times a string is wound around a circular spatial dimension
space-time diagram	A plot of time as the y coordinate and space as the x coordinate, with the three spatial dimensions collapsed to one dimension
converging lens	A lens that can refract a parallel beam into a convergent beam
galaxy	Even the nearest and fastest stars require centuries to move a degree or more.
ram	Random access memory
aurigae	see Capella
magnetic pressure	The pressure exerted by a magnetic field on the material that contains the field
critical equatorial velocity	In rotating early-type stars, that velocity at which the ratio of centrifugal force to gravity at the equator is unity
u	the symmetry group associated with electromagnetic gauge invariance
crystal fracture	Crystals fracture in the same way anything would fracture
radial orientation	A term that may be used to describe the orientation of a charge, particularly (but not exclusively) that of a star - for example: the star and crescent on the national flag of Pakistan are placed on a diagonal line bisecting its green panel, whilst the star on the national flag of Turkey is orientated towards the hoist and that on the flag of Sarawak has one point along the diagonal meridian – the rotational position (see also ‘star 1)').
a spectral class	Hot white stars (7,500 -10,000 K effective temperature)
signal meter	A signal meter is used to determine the strength of a satellite signal for the purpose of properly aligning a satellite dish.
astrolabe	(a) Ancient Arabic and medieval alt-azimuth device comprising two or more flat, metal, calibrated discs, attached so both or all could rotate independently
extended dimension	A space (and spacetime) dimension that is large and directly apparent; a dimension with which we are ordinarily familiar, as opposed to a curled-up dimension
chaos	Distinctive area of broken terrain on a planetary surface.
spectrometer	An instrument for tracing the intensity of a spectrum at different wavelengths; the result is a graph.
worm hole	A hypothetical shortcut through the space time continuum.
wavelength	(1) The length of the wavelike characteristic of electromagnetic radiation; (2) in any wave, the distance from one maximum to the next.
pechlorates	These are a type of salt that have been found on the surface of Mars by the Phoenix lander
colles	small hills or knobs.
gravity	A force that pulls two or more things together.
h ii condensation	A high-density H II region
pulse rate	The number of times a heart beats per minute in a person's body.
symmetry	(a) A property of a physical system that does not change when the system is transformed in some manner
line profile	A plot of intensity versus wavelength across a spectral line
tornadoes	SUPERCOOLING
fusion	The process in which two atoms join together to make a different atom, usually releasing a huge amount of energy in the process
rv tau variables	Periodic variables with periods 60-100 days, and of spectral types G and K
scattering matrix	The S-matrix relates the incoming and out-going states of elementary particles during interactions and scattering experiments
silicon chip	A small crystal of silicon semiconducter used in electronics.
andromeda galaxy	, M33, and more than 25 smaller galaxies
universal law of gravitation	Newton's expression for gravity, which states that the gravity force between two objects is equal to the product of their masses divided by the square of the distance between them, multiplied by the gravitational constant.
earth	has been observed to fall towards the center of the
continuous spectrum	(a) A spectrum composed of a continuous range of emitted or absorbed radiation
absorption edges	Sudden rises superposed on the smooth decrease of the curve of the attenuation coefficient, which cause the curve to have a typical sawtooth aspect
vlti	Very Large Telescope Interferometer [LLM96]
k	Kilo (thousand).
absorption nebula	A type of nebula that blocks light from sources behind it
plate tectonics	Motions of a planet's lithosphere, causing fracturing of the surface into plates
rankine scale	A temperature scale with the same division as the Fahrenheit scale and the zero point at 0° absolute
sedimentary rock	A rock type that has been created by the deposit and compression of sediment
horizon	The visible juncture of Earth and the sky, represented in a horoscope by the Ascendant-Descendant axis.
mpeg	MPEG is a type of compressed video created by the Moving Picture Experts Group.
kelvin	0 Kelvin is absolute zero; H2O melts at 273 K (= 0° C = 32° F); H2O boils at 373 K (= 100° C = 212° F)
metal-rich	Having a high metallicity with respect to olar
bladed habit	This is a crystal shape that resembles a knife blade because is has very thin layers
fossa	long, narrow, shallow depression.
longitude	Longitude represents angle east or west of the Prime Meridian, which since 1884 has been taken to be the meridian running through the site of the Royal Observatory at Greenwich, England
diode	An electronic, semiconductor device that allows current flow in only one direction.
ionization	(a) Loss or gain by an atom of one or more electrons, by which process the atom becomes an ion and instead of being neutral, has a charge: positive if it has lost an electron, negative if it has gained one
bode's relationship	Bode's relationship gives an approximate indication of the comparative distances of the planets from the sun
evapotranspiration	The evapotransipration is the transfer of water from Earth's surface to the atmosphere
61 cygni	The first star other than the Sun to have its parallax, and hence distance, measured
complex analytic	A particular property of mathematical representations of physical or mathematical systems
endothermic process	An adjective applied to a reaction in which a net input of energy is required for the reaction to occur
centauri	A binary system (G2 V, K5 V) 1.3 pc distant
rhenium	Symbol:"Re" Atomic Number:"75" Atomic Mass: 186.21amu
galaxy	. While all celestial objects appear to move across the sky from hour to hour because of the rotation of the
bar	= 0.987 atmosphere = 1.02 kg/cm^2 = 100 kilopascal = 14.5 lbs/square inch.
gin pennant	In British RN and some other usage, an unofficial pennant of varying design – now often a defaced version of the starboard pennant in the NATO signalling code – raised when a ship’s officers wish to entertain the officers of another ship or ships (see also ‘pennant 2)’ and ‘senior officer afloat pennant’).
spiral density wave	A wave, due to a local increase in the gravitational field, that produces a series of alternate compressions and rarefactions as it propagates with fixed angular velocity in a rotating galaxy
bar	(a) The absolute cgs unit of pressure equal to 106 dyn cm-2
aphelion	The point in an object's orbit around the Sun when it is furthest from the Sun.
apoapsis	The farthest point in an orbit from the body being orbited.
barotropic bas	A gas in which the pressure is a function of the density only
neutral	An object that does not have a positive or negative charge.
hour angle	Odin was the king of the gods...
conjunction	The phenomenon in which two bodies have the same apparent celestial longitude (see Longitude, Celestial) or right ascension as viewed from a third body
clouds of magellan	see Magellanic Clouds
consistent	The property possessed by a scientific theory when it contains and extends an earlier well-supported theory; for example, general relativity is consistent with Newtonian gravity
luminance	Symbol: Lv A measure of the brightness of an extended source (one that cannot be considered a point)
kelvin scale	The temperature scale most commonly used in science, on which absolute zero is the lowest possible value
crater density	Number of craters of a certain size and larger per unit area
constellation	A pattern of stars identified by name
apodization	A mathematical process performed on the data received from an interferometer before carrying out the calculations of the Fourier transformation to obtain the spectrum, in order to modify the instrumental response function
sc stars	Stars which appear to be intermediate in type between S stars and carbon stars (C/O ratio near unity)
upright centred cross	See ‘cross 1)’.
red shift	he lengthening of the wavelength of electromagnetic radiation caused by relative motion between source and observer
zenith	The point directly overhead.
central meridian	The central meridian is an imaginary line through the center of the disk from the south pole to the north pole, dividing the disk into equal halves, independent of phase
lunarplanetins	Report of the Workshop on Unmixing the SNCs: Chemical, Isotopic, & Petrologic Components of Martian Meteorites
ecliptic	An imaginary line in the sky traced by the Sun as it moves in its yearly path through the sky.
kaiserliche kriegsflagge	An Imperial War Ensign – but see ‘war flag 1)' and ‘war flag 2)'.
zenith	Your zenith is the point in the sky directly above your head
convergent	Coming together
tully-fisher relation	A relation used to determine the absolute luminosity of a spiral galaxy
light-year	distance light travels in a vacuum in one year, approximately 5.88 trillion miles
fesslet	A heraldically derived term intended to mean a single, narrow horizontal stripe – but see ‘bar’, ‘barrulet' and ‘filet' (also ‘fess').
causality	Principle that a cause must precede its effect
wave	A disturbance which moves through or over the surface of the medium with speed dependent upon the properties of the medium.
micrometry	The measurement of the apparent sizes and separations of astronomical objects by use of knife blades or crosshairs in the eyepiece of a telescope
europium	Symbol:"Eu" Atomic Number:"63" Atomic Mass: 151.96amu
special relativity	a branch of relativity dealing with the behavior of objects traveling close to the speed of light
in fess	The heraldic term used when an object, charge or charges on a shield, a banner of arms or any quartering thereof appear in a horizontal position – fesswise (see also ‘banner of arms', ‘fess’, ‘per fess’ and ‘quartering 1)’).
brillouin scattering	Slight changes in the frequency of radiation, caused by reflection or scattering from the high-frequency sound waves that arise from thermal vibrations of atoms in the medium
strange particles	The collective name for a group of strongly interacting particles possessing the property of strangeness
hyperon	(a) A baryon with non-zero strangeness
galactic halo	Spherical regions around spiral galaxies that contain dim stars and globular clusters
inconjunct	A minor hard aspect, 150°, synonymous with quincunx
frontogenesis	FROST
handled	A term sometimes used to describe the hilt and pommel of a sword or dagger and the haft of a hammer, axe or other tool – but see ‘hafted’ and ‘hilted’ (also ‘shafted’).
superconductor	A piece of superconducting metal below the transition temperature at which superconductivity sets in
calcium star	Old name for an F star
gyrochronology	Scientists have found a more accurate way to calculate the ages of stars
ev	Electron volt, a measure of the energy of subatomic particles.
angular size	The angle subtended by an object on the sky
astronomical unit	(AU) A measure of distance equal to the average distance between the Earth and the Sun
line blanketing	The combined effects of spectral lines upon the emergent energy distribution from and the temperature distribution in a stellar or planetary atmosphere
zenith	The point on the celestial sphere directly above an observer, or the highest point in the sky reached by a celestial body.
triangulation	The process of determining the height and distance of a target by measuring the difference in its angular position as seen from two or more sites of known (or measurable) separation
cyclones	A cyclone is a low pressure system in the atmosphere
radiant	The area in the sky where during a meteor shower the meteors appear to radiate from.
arcminute	A small unit of angular measurement, spanning one-sixtieth of a degree; an arcsecond is one-sixtieth of an arcminute
altitude	(a) Angular distance above the horizon
blaze angle	The tilt of the facets or grooves of a diffraction grating
eit	Extreme ultraviolet Imaging Telescope, solar observation instrument on the SOHO satellite
kwf	Keyword file of events listing DSN station activity
nonagesimal	The point 90° from the Ascendant
callippic cycle	76-year cycle for
thermodynamic equilibrium	(a) The state reached ultimately by an isolated system.[D89]
bohrium	A synthetic radioactive element first detected by bombarding a bismuth target with chromium nuclei
spectrum variables	Main-sequence Am or Ap stars whose spectra show anomalously strong lines of metals and rare earths which vary in intensity by about 0.1 mag over periods of about 1-25 days
solar neutrino unit	1 SNU = 10-36 solar-neutrino captures per second per target atom
eightfold way	classification scheme for elementary particles established c
logarithm	From the Latin logarithmus, literally mathematical proportion or ratio
nodule	a semi-spherical fragment of rock embedded in a matrix with a different composition.
aspect ratio	Ratio of the major axis (e.g., of a rocket) to the minor axis
hierarchy problem	In the context of grand unified theories, the hierarchy problem is our inability to understand theoretically why the energy scale at which the unification becomes apparent, about 1016 GeV (billion electron volts), is so much higher than other energy scales of relevance to particle physics, such as the mass/energy of a proton, which is only 1 GeV
gravitational encounter	The encounter between two massive bodies which results in the deviation from their original directions of motion
gravitational-lens effect	The effect of matter in curved spacetime, which tends to focus any beam of radiation from a distant source
central peak	Exposed core of uplifted rocks in center of a complex impact crater
bessel equation	A linear second-order differential equation, the solutions to which are expressible in mathematical functions known as Bessel functions
causality puzzle	see Horizon Problem
speed of light	The fastest known speed possible at 299,792.458 kilometres per second.
backing	VERNAL EQUINOX
coherent receivers	These devices respond to the electric field strength of the signal, and can preserve phase information about incoming photons
recombination	(a) The capture of an electron by a positive ion
standing wave	A pattern of oscillations in space in which the regions of maximum displacement and of zero displacement (the nodes) remain fixed in position
initial condition	(a) In physics, the state of a system at the time at which a given interaction begins - e.g., the approach of two electrons that are about to undergo an electromagnetic interaction
astrochemistry	The branch of science that explores the chemical interactions between dust and gas interspersed between the stars.
quartered	1) In strict (English) heraldic usage the term for where a shield or banner of arms is divided into four or more quarters but which are taken from two or more previously unconnected sets of arms is in, for example, the royal standard of England 1340 – 1605 or France and England quartered - but compare with ‘quarter the arms' (see also ‘banner of arms', ‘quarter', ‘quartering', ‘quarterly' and ‘shield 1)') 2) See ‘quarterly'.
pyroclastic	The type of rock formed from fragments or ash resulting from volcanic activity, especially the hot, fast-moving dense clouds that occur during an eruption.
lifetime	The time it takes for a sample of identical particles to decay to 1/e of its initial population (e 2.718)
continuous	Smoothly varying; taking any value
coriolis force	A `fictitious' force used to describe the motion of an object in a rotating system
bound-bound transitions	Transitions between energy levels of an electron bound to a nucleus (the electron is bound both before and after the transition)
raobs	RADiosonde OBServations
newton's law of gravitation	Two bodies attract each other with a force that depends on the product of their masses divided by the square of the distance between them
jehovah sun	The term – and a direct translation of the German Jehovasonne – which may be used to describe a sun in splendour, surmounted by a cartouche bearing the name of God in Hebrew lettering - a charge sometimes to be seen on (exclusively Protestant) German military flags of the 16th and 17th Centuries (see also ‘cartouche’, ‘sun-in-splendour’ and ‘surmounted by’).
convection	the physical upwelling of hot matter, thus transporting energy from a lower, hotter region to a higher, cooler region
wavelength	The distance between successive peaks in a traveling wave
topology-changing transition	Evolution of spatial fabric that involves rips or tears, thereby changing the topology of space
intelligence	The capability for abstract thought, coupled with a mastery of tools or technology
gravitational instability	A condition that occurs when an object’s inward-pulling gravitational forces exceed the outward-pushing pressure forces, thus causing the object to collapse on itself
biological evolution	The natural development over time from simple to complex organisms, generated by mutations that change the gene structure and directed by natural selection of those individuals best-adapted to the enviroment.
right ascension	Odin was the king of the gods...
semi-quintile see	decile.
schröter effect	The strange observational effect phenomenon in which Venus's disc reaches half phase a few days before or after the predicted date.
geostrophic wind	ZULU TIME
self-organisation	spontaneous emergence of order, arising when certain parameters built in a system reach critical values
space charge wave	An electrostatic wave brought about by oscillations of the charges
faculae	Bright patches that are visible on the Sun's surface, or photosphere.
coupled substitution	Substitution in which the charges of substituting ions are not same and charge balance is achieved by a second substitution on a different crystallographic site
topology	(a) The branch of mathematics that treats the `large-scale' structure of curved spaces
escape velocity	The minimum velocity required for an object to escape the gravity of a massive object.
image spectrometers	Refers to a class of instruments which preserve the image field while also determining the spectrum
magnetopause	Boundary between the magnetosphere and the solar wind.
particle accelerator	a machine that, using electromagnets, can accelerate moving charged particles, giving them more energy
union pendant	See ‘budgee pendant’.
volume	amount of space an object occupies.
cosmology	The study of the Universe, its structure and evolution.
gut	Grand Unified Theory
sphere	The outer surface of a ball
azimuth	Angular distance measured clockwise around the observer's horizon in units of degrees; astronomers usually take north to be 0 degrees, east to be 90 degrees, south to be 180 degrees, and west to be 270 degrees.
equilibrium constant	Value that expresses how far the reaction proceeds before reaching equilibrium
coulomb barrier	(a) Electromagnetic zone of resistance surrounding protons (or other electrically charged particles) that tends to repel other protons (or other particles of like charge)
individual flag.	In U.S
collimation	Alignment of a beam so that the photons can be directed at a well-defined part of a target
mixer	The critical element of a radio detection system which allows the incoming wave to be combined with the reference frequency from the local oscillator
saturn's satellite system	A family of at least 18 moons orbiting Saturn, ranging from 20 km diameter up to a size slightly exceeding that of the planet Mercury.
zamg	Central Institute for Meteorology and Geodynamics
oe	O-type stars with emissions in the Balmer lines
positive signs	All air and fire signs; used to describe the outgoing, dynamic qualities characteristic of these signs
canis minoris	see Procyon
lamb of god	See ‘agnus dei’.
erbium	Symbol:"Er" Atomic Number:"68" Atomic Mass: 167.26amu
aperture synthesis	The method of combining the signals received by several smaller telescopes distributed over a very large area or baseline to provide the angular resolution of a much large telescope
crucial experiment	An experiment that has the power to decide between two competing theories
nl	Newsletter
right ascension	along with declination, a means of defining the position of objects in space, referred to a known point
ae aurigae	An O9.5 V runaway star
‘e’ cross	See ‘two-and-a-half armed cross’.
middle latitudes	TEMPERATURE
radiative recombination	See radiative capture
diffluence	CONSTANT PRESSURE CHART
galaxy	is proportional to its distance from the
evolved star	a star that is near the end of its life cycle where most of its fuel has been used up
wake	See trail.
arc	In astrology, the curved path of a stellar body and the angular measurement of this path.
tatzenkreuz	See ‘cross pattée’ in ‘appendix VIII’
equation of center	In elliptic motion the true anomaly minus the mean anomaly
throughput	A measure of the efficiency of an optical system
half-life	(a) The time it takes for half of a given quantity of radioactive material to decay
wave	A propagating pattern of disturbance
standstill	Odin was the king of the gods...
astrometry	The study of positions and motions of the stars.
lobes	In radio astronomy, regions of sensitivity in an antenna pattern
argand diagram	a diagram in which the length and phase-angle of a complex quantity is displayed
constellation	in ancient astronomy, a pattern formed by prominenet stars in the night sky associated with a cultural or mythological person or object; the Greek astronomer Ptolemy identified 48 constellations in his Almagest (2nd century); in modern astronomy, one of 88 internationally defined areas of the celestial sphere (see: 88 Constellations List)
decimal	The number of digits to the right of the decimal point in a number.
negative signs	Earth and water signs; an alternate term used to describe "feminine" characteristics of receptivity and passivity
stability	A measure of how hard it is to displace an object or system from equilibrium
ecliptic	The plane of the Earths orbit around the Sun, inclined at about 23.4 degrees to the equator, due to the Earths tilt.
international atomic time	TAI The continuous scale resulting from analyses by the Bureau International des Poids et Mesures of atomic time standards in many countries
tide tables	Tides tables provide predicted times and heights of the high and low waters associated with the vertical movement of the tide
inflaton	The name given to whatever fields are responsible for driving inflation
eclipse	A chance alignment between the Sun, or any other celestial object, and two other celestial objects in which one body blocks the light of the Sun, or other body, from the other
latitude	TROPIC OF CAPRICORN
ftp	File Transfer Protocol
thermal convection	The energy transfer in a fluid by a mechanism of bulk hydrodynamic movement
high-velocity star	(a) A star whose U and/or V and/or W velocities are much greater or much less than zero
perturb	to cause a planet or satellite to deviate from a theoretically regular orbital motion.
sublattice magnetization	in an antiferromagnet the magnetic atoms can be divided into two equivalent classes, each magnetized in opposite directions
magneton	see Bohr Magneton [H76]
calibration	the process of comparing a field instrument to a measurement standard, in order to insure the instrument is reading the correct values
astigmatism	(a) A common eye defect in which the observer cannot focus clearly on objects at any distance
irregular galaxy	A galaxy that appears disorganized and disordered, without a distinct spiral or elliptical shape
atomic orbital	Representation of the electron cloud surrounding an atom
radical chart	The natal horoscope
azimuth	Azimuth is the angular distance around the horizon measured eastward in degrees from the North Horizon Point
address group	In US naval usage and in some others, the group of signal flags displayed by a vessel with a flag officer or unit commander embarked, and flown (together with a call sign hoist) when entering or leaving harbour - see ‘call sign hoist' (also ‘signal flag' and ‘signal hoist').
equator	An imaginary circle around a body which is everywhere equidistant from the poles, defining the boundary between the northern and southern hemispheres.
chemical clock	an asymptotically stable regime of a chemical system in which the concentrations of the reagents are periodic functions of time
bifurcation	a phenomenon whereby the number of solutions of certain type presented by a dynamical system changes abruptly, as one of the parameters defining the dynamics crosses a critical value
trajectory	The line of motion of a meteor relative to Earth, considered in three dimensions.
civil twilight	the time of morning or evening when the sun is 6° below the horizon
secular stability	The condition in which the equilibrium configuration of a system is stable over long periods of time
alpha particles	Particles first discovered in radioactive decay, and later identified as helium nuclei (two protons and two neutrons bound together)
arcuate	having the form of a bow; curved; arc-shaped
vector	A quantity which has both magnitude and direction, such as the spin of a magnetic atom in the Heisenberg model
equilibrium position	The position of an oscillating body at which no net force acts on it
extragalactic distance scale	The set of distances to astronomical objects outside our galaxy
akashic records	The memory of nature
prf	Pulse Repetition Frequency, the rate at which (typically) a radar emits transmit pulses.
geology	Geology is the study of the Earth's structure.
luminosity distance	(a) Any distance to a celestial object which has been calculated using a standard candle
instability strip	A region on the HR Diagram occupied by pulsating variable stars such as Cepheids.
region 10	The region of American Mensa, Ltd
interference filter	(a) A filter used to shut out all light except the desired wavelengths
cabled	The term for a charge, particularly an anchor, that is shown complete with its cable – but see ‘foul anchor’ (also ‘charge’).
climate model	A climate model is a simplified representation of the climate system, generally in the form of a set of mathematical equations
bdl	Bureau des Longitudes
coronal equilibrium	The equilibrium in which collisional ionizations balance radiative recombinations
carinae	see Canopus
balmer jump	The sudden decrease in the intensity of the continuous spectrum at the limit of the Balmer series of hydrogen at 3646 Å, representing the energy absorbed when electrons originally in the second energy level are ionized
monodromy	The property that all paths of points of a body simply rotating about an axis shall return into themselves
gravitation	(a) The universal ability of all material objects to attract each other; F = Gm1m2 / r2
complexity	in information sciences, complexity measures the length of the shortest description of a given (finite) sequence of symbols
apastron	the point of greatest separation of two stars, such as in a binary star system.
low noise converter	A low noise converter is located at the focal point of the antenna of a parabolic satellite dish
pds	Payload Data Segment, comprises all those elements which are related to payload data acquisition, processing, archiving and those concerning the user interfaces and services.
maximum	MIST
chemical differentiation	The separation of different elements, often heavier elements from lighter elements, as a consequence of different chemical reactions
gis	Gas Imaging Spectrometer (ASCA X-ray satellite).
relativistic cosmology	Cosmological applications of Einstein's theory of general relativity
lyapounov exponent	measures the rate of exponential separation of initially nearby states of a dynamical system
interloc	A newsletter for anyone who wants to know more about what is going on with the AMC and the national office
ibd	International Board of Directors
euclidean geometry	The geometry developed by the Greek Euclid about 300 BC
stationary wave	A standing wave; the pattern formed when two waves of the same amplitude and frequency move simultaneously through a medium in opposite directions
night	SATURATE
cellulose	A polysaccharide (carbohydrate) found in plants
dissociate aspect	An aspect within orb but out of sign
retarder	A device for introducing a phase delay, such as half-wave or quarter-wave, between two orthogonally polarized components of an electromagnetic wave
altazimuth	A telescope mount which has its two axes of movement aligned with the horizon and the zenith.
culmination	A term used to describe a planet's arrival at the Midheaven (natally or by progression or transit); also used to indicate the completion of an aspect by progression, i.e., when a platic aspect reaches partile, it culminates.
cadmium	Symbol:"Cd" Atomic Number:"48" Atomic Mass: 112.41amu
great circle	A circle described on the surface of a sphere (Earth, for example) so that its plane passes through the center of the sphere.
geologist	A scientist who studies the formation, structure, history and processes (internal and surface) that change Earth and other planetary bodies.
cation	Positively charged ion.
cetus arc	A gaseous nebula, probably about 100 pc distant, centered on or near Peg
specific heat	The amount of heat it takes for a substance to be raised 1°C.
soliton	A finite-amplitude hydrodynamic disturbance which is propagated through a fluid without any change of shape
berossos	(280 B.C.) Babylonian
critical point	Point along a phase boundary on a phase diagram where the liquid and gas states cease to be distinct
wmo	World Meteorological Organization
composite chart	A single horoscope made up from two or more natal charts by averaging house cusps and planetary positions of the natal charts
fp	Fabry-Perot [LLM96]
earth	's rotation axis onto the sky
albedo	Fraction of the light and energy received that is reflected or diffused by a non-luminous body
galaxy	A collection of star systems
edl	(Atmospheric) Entry, Descent, and Landing.
open crown	See ‘coronet’.
constellation	a pattern of stars that are grouped together in the sky.
great year	The period when the pole makes a complete circle.
sautant	The French for “leaping”, which is also sometimes used in place of, or in addition to, the heraldic terms rampant or salient – see ‘rampant’ and ‘salient’ in ‘appendix V’ (also ‘erect’ in ‘appendix V’).
radio astronomy	Study of the universe at the radio wavelengths of electromagnetic energy
average	The best estimate of a quantity based on multiple measurements, given by sum of independent values divided by number of measurements made
phase	The angular distance between peaks or troughs of two waveforms of similar frequency.
overtide	A shallow water harmonic tide constituent with a speed that is a multiple of the speed of one of the basic constituents of the tide-producing force
weight	A measure of the force due to gravitational attraction.
light year	The distance which a ray of light would travel in one year
filament	Long structure that can be seen on the Sun near magnetic field reversal lines
cno stars	Late O-type or early B-type stars (O8 to B4) in whose spectrum the lines of some of the elements C, N and O are weaker or stronger than in the standard stars
dmcii	Disaster Monitoring Constellation Imaging International - DMCii website DMCii is a UK company which coordinates the Disaster Monitoring Constellation services
lrac	Low Rate Reference Archive Centre, colocated with the Payload Data Handling Station in Kiruna
harkins's rule	The rule that atoms of even atomic number are more abundant than those of odd atomic number
horizon distance	the maximum distance, at any given time, that a light signal could have travelled since the beginning of the Universe
nautical mile	FEEDER BANDS
meridian flip	This is the process that equatorial mount owners have to go through to make sure that their equipment doesn't collide with a pier or other obstruction as it tracks across the night sky.
bohrium	Symbol:"Bh" Atomic Number:"107" Atomic Mass: (264)amu
zonal flow	MESOCYCLONE
elevation	see azimuth and elevation.
convergence	DOG DAYS
jet stream	CUT-OFF HIGH
magnetic monopole problem	A problem, discovered by John Preskill in 1979, concerning the compatibility of grand unified theories with standard cosmology
demi	The heraldic term used when the front or upper half of an animal, or one-half of another charge is shown on a shield, banner of arms or a flag but see note below – demy or semi.
random error	Error that can be reduced when separate observations are combined
saros cycle	Odin was the king of the gods...
pallet	The heraldic term for a vertical stripe whose centreline often (but by no means exclusively) lies along the vertical meridian of a shield, a banner of arms or any quartering thereof, and which (in strict heraldic usage) should occupy about one-quarter the width of that shield, banner of arms or quartering – but see ‘Appendix VI’, ‘paly' and ‘pale' (also ‘banner of arms').
collider	an apparatus to accelerate ions and other particles to study or utilise the effects of high-energy collisions
light cone	(a) The history, in space-time, of a light flash
finite	With an edge, not going on forever.
swell	WINTER
granulation	Granulation consists of solar granules together with intergranular lanes (dark, cool areas between granules where solar material is descending into the surface)
sunspot	A cooler region of the Sun's photosphere (which, thus, appears dark) seen as a spot, on the Sun's disc
valence band	The highest completely filled energy band of a solid
cristobalite	Silica group mineral occuring in terrestrial volcanic rocks, martian and lunar meteorites, and chondrites
shock	unusually high pressures produced briefly by an impact
prograde	The movement of a body in an anticlockwise direction around the Sun or anticlockwise rotation on its axis as seen from above the Suns north pole
metar	FREEZING POINT/FREEZE
perihelion	The point in its orbit where a body traveling round the Sun is closest to the Sun.
sun	A medium size star that lies in the middle of our Solar System.
panicles	A term used when loosely branching clusters of flowers and/or foliage form a wreath, such as the panicles of rice on the army rank flags of Taiwan (see also ‘rank flag 1)’ and ‘wreath 1)’).
facula	bright spot.
neap tide	The tide which occurs near a quarter lunar phase, causing the variance between high and low tide to be minimal.
multiple conjunction	A planetary arrangement in which three or more planets form a series of conjunctions that may extend from one sign into another
condensation nuclei	Dust grains in the interstellar medium which act as seeds around which other material can coagulate
karma	The end result of the law of cause and effect in relation to the totality of one's actions in one of the successive states of existence, viewed as a preparatory phase for the next state.
red shift	The lengthening of the wavelength of electromagnetic radiation caused by relative motion between source and observer
fogbows	PHOTOSPHERE
optical path difference	The difference in path length between the actual wavefront in an optical system and the equivalent spherical wavefront
hafted	The heraldic term used when the handle of a hammer or an axe/mace (or of a similar tool/weapon) is of a different tincture to its head – but see ‘hilted’ (also ‘barbed’, ‘garnished’, ‘shafted’ and ‘tincture’).
superposition principle	A quantum mechanical principle according to which any two states can be combined (actually in infinitely many ways) to form states which have characteristics intermediate between those of the two which are combined
planetessimal	This is the name given to the small rocky bodies that form in young planetary systems
tornadoes	TIDE
rayleigh limit	The minimum resolvable angle between the wavelengths of two spectral lines
fictional flag	A flag that appears in a work of fiction either visual or written - which may or may not have physical existence as a flag - but which is (entirely or largely) a product of the author’s imagination (see also ‘fictitious flag’ below).
radiative viscosity	The friction produced by the collisions between matter and radiation
drought	HAIL
system of knowledge	Ways of dealing with information, such as superstition, appeals to authority, and the advocacy system
micrometeorites	An extremely small object
heterotic o-string theory	heterotic O(32) String Theory One of the five superstring theories; involves closed strings whose right-moving vibrations resemble those of the Type II string and whose left-moving vibrations involve those of the bosonic string
plate tectonics	The motions of the plates which make up the crust of the Earth.
betelgeuse	A red supergiant star that is located approximately 650 light years away in the Orion constellation
composition percentage	This value tells the percentage of a solution that could be a percentage of mass or percentage by volume
dinosaurs	large animals that lived in the Mesozoic Era from 230 to 65 million years ago; most probably wiped out by the impact of a large asteroid or comet.
marching subpulse	The weaker component of a pulsar pulse when its period is more than half that of the main pulse, so that the subpulse occurs at progressively later intervals between successive main pulses
tithi	The time it takes the angle between the sun and the moon to wane or wax by 12°; used in
ground state	(a) The lowest energy state of an atom, molecule, or other system
occultation	An alignment of two bodies with the observer such that the nearer body prevents the light from the further body from reaching the observer
vastitas	widespread lowlands.
planitia	a low plain.
conjunction	An event that occurs when two or more celestial objects appear close close together in the sky.
ergosphere	region surrounding a spinning black hole, between the static limit and the outer event horizon, in which it is impossible to be at rest
photosphere	Surface of the Sun that is visible in white light
inclination	Angle between the plane in which a body orbits and the equatorial plane.
tapered swallowtail	See ‘broad command pennant', ‘burgee 1)’, ‘burgee 2)’ and ‘burgee command pennant’.
magnetic-dipole radiation	Radiation emitted by a rotating magnet
iram	Institut de RadioAstronomie Millimetrique
aiguillette	Loops of ornamental braided cord with tassels, and worn from the right or left shoulder of (usually but not invariably) military uniforms to signify a special status or service – see ‘flag adjutant' (also ‘cord(s)' ‘dress knot') and ‘lanyard 1)')
sparticles	Hypothetical particles which are predicted by some Grand Unified Theories
lagrangian	(a) A mathematical expression summarizing the properties and interactions of a physical system
galaxy counts	A quantitative measure of how many galaxies there are in each range of luminosity and at each range of distance from earth
breit-wigner equation	An equation relating the cross section in a nuclear reaction to the energy of the incident particle
multiplex	Combining many signals into one or a small number of signals
supernova	Stage in the life of a massive star, manifesting itself by an explosion that makes it extremely bright for a time.
ligo	Large Interferometric Gravitational Wave Observatory
wavelength	On a periodic curve, the length between two consecutive troughs (low points) or peaks (high points).
electromagnetic radiation	(a) "Waves" of electrical and magnetic "disturbance", radiated as visible light, radio waves, or any other manifestation of the electromagnetic spectrum
convolution	A mathematical combination of two functions which involves multiplying the value of one function at a given point with the value of another function, the weighting function, for a displacement from that point and then integrating over all such displacements
rossby number	This gives the ratio of the inertial to the Coriolis forces in a moving fluid
stellium	A multiple conjunction that occurs within one sign or house, indicating a focal point of energy or interest
lowest normal tide	In present usage it is synonymous with LLWLT, but on older charts it may refer to a variety of low water chart datums.
celestial object	an object in space which appears in Earth's sky
dust	microscopic grains in space that absorb starlight; the grains are "soot" left by dying stars, and they will sometimes clump together in huge dark clouds
circumpolar	An object that does not set from its observer's latitude.
colloquium	A gathering for serious thought, not just for fun
epoch	The particular date for which astronomical positions in a book or table are accurate
porphyry	Philosopher (233-304 A.D.) of the Neo-Platonic school who devised a house system based on dividing each quadrant of a horoscope, as determined by the angles, into three houses of equal size.
reciprocal	The inverse of a number; for example, the reciprocal of 3 is 1/3, the reciprocal of 1/2 is 2
light	Polarisation is a condition in which the planes of vibration of the various rays in a light beam are at least partially aligned.
groundstate	The ground state is the lowest energy state of a nucleus.
porphyritic	A geology term used to describe large crystals found in igneous rock.
opposition	One of the major Aspects in a chart
autumnal equinox	The point at which the Sun crosses the celestial equator moving southward
rvc - regional vice-chair	This is an elected office that is elected by and represents their region on the AMC
impact	When one body strikes another with great force
inclination	The angle that the plane of a body's orbit makes with a reference plane through the object it is orbiting, or the angle made by the body's axis of rotation with a line perpendicular to that reference plane
crystallization	SUBPOLAR
meter	(a) The SI unit of length
achrome	The French for colourless – but see ‘monochrome 1)'.
impact	a collision between two planetary bodies
conjunction	the moment when two celestial objects lie closest together in the sky
nm	Nautical Mile, equal to the distance spanned by one minute of arc in latitude, 1.852 km.
statistical weight	g: The probability that the state will appear under a given set of conditions
bolometer	A sensitive radiation detector.
energy gap	A range of energies in a solid for which there are no quantum states of the electrons
telescope	An instrument for seeing faint and distant objects more clearly
supra-thermal	High-energy
system noise	The noise in a radio telescope; composed of the receiver noise and the sky noise
hubble law	The observed linear relationship between the distance of a galaxy and its velocity of recession
station pressure	PRESSURE TENDENCY
tectonics	The process that forms planetary features such as continents, mountains, and faults by motion of sections (plates) of the Earth's crust driven by convection currents in the Earth's mantle.
aspect pattern	Particular combinations of aspects that form special planetary configurations.
nocturnal	From the Latin nocturnus, of night
first order transition	A phase transition is called first order if it occurs in a manner similar to the way water boils
baryon number	(a) The total number of baryons in the universe, minus the total number of antibaryons
isophotes	Lines connecting points of equal light intensity
consciousness	Any entity's innate capacity for relationships
rattlesnake	The image of a venomous snake (usually accompanied by the motto "don't tread on me") that is depicted either coiled or stretched - it appeared on several early American flags and may be seen on the current US naval jack – see the note following ‘union jack'.
inescutcheon	The heraldic term for one shield appearing within another (usually – but not invariably - at its centre point) or on a banner of arms (see also ‘banner of arms', ‘coat of arms’ ‘escutcheon’, ‘escutcheon of pretence 1)', ‘overall’ and ‘quartering 1)’).
density	degree of "solidity" of a body: its mass divided by its volume
federal service flag	The term used in Austria and Germany for the flag flown by agencies of the federal government - see ‘state flag 1)’ (also ‘state service flag 1)’).
harmonic constants	The amplitudes and epochs of the harmonic constituents of the tide, or tidal current at any place.
meridian	an imaginary line connecting a point due south on the horizon with a point due north on the horizon and going through the zenith
gff	Giga French Francs
mesosphere	Region of the atmosphere situated at an altitude of approximately 50 to 80 kilometers.
zhongqi	Name of a major solar term of the Chinese calendar
metastable	A state which is not stable, but which lives long enough to have significance, is called metastable
first point of aries	Z Zenith: The point on the meridian directly above an observer.
castor	A visual triple system about 14 pc distant
basin	Basins or impact basins are the results of massive impacts on a planetary surface
fractal geometry	generalisation of Euclidean geometry suitable for describing irregular and fragmented patterns
bright blue variables	Early-type high-luminosity stars with peculiar spectra and large-amplitude light variations over a long time scale (e.g
anthropomorphism	The projection of human attributes onto nonhuman entities such as animals, the planets, or the Universe as a whole
storm track	The storm track is the path that cyclones tend to follow in mid-latitudes
focal plane	The plane (usually this is actually the surface of a sphere of large radius) where the image is formed by the main optics of the telescope
microchannel plate	A compact electrostatic high-voltage electron multiplier with a very large number of narrow pores or channels
partile	The degree at which an aspect is precisely exact (0° orb)
elongation	Angular distance of a celestial object from the sun in the sky; more simply, how far above the horizon an inferior planet is above the horizon.
zero curvature	The curvature of a surface or space in which parallel lines remain parallel and the sum of the angles of a triangle is exactly 180 degrees.
gregorian	A class of reflecting telescope which uses a concave secondary mirror placed after the prime focus is reached instead of a convex secondary placed before the prime focus
parabola	A curve that extends to infinity as its arms become parallel
mtf	Modulation Transfer Function [LLM96]
charge multiplet	A group of particles (such as the two nucleons or the three pions) which differ in electrical charge but which are nearly identical in mass and other respects (such as lifetime and angular momentum) and which seem to experience identical nuclear forces
haurient	See ‘appendix V’.
yttrium	Symbol:"Y" Atomic Number:"39" Atomic Mass: 88.91amu
achromatic lens	(a) Lens (or combination of lenses) that brings different wavelenghts within a ray of light to a single focus, thus overcoming chromatic aberration
urban crown	See ‘mural crown 1)’.
coesite	High pressure polymorph of silica produced during shock metamorphism at over 20 kilobars
mixed	A type of tidal current characterized by a conspicuous difference in speed and duration between the two flood currents or two ebb currents occurring each tidal day.
equation of time	an astronomical term accounting for changes in the time of solar noon for a given location over the course of a year
station elevation	STEAM FOG
echelon	A type of diffraction grating consisting of a number of equal thin glass sheets stacked on a slant
chemical equation	An expression of a fundamental change in the chemical substances.
knatterflagge	See ‘vertically hoisted flag 1)’ and its following note.
latitude	ARCTIC AIR MASS
electroweak interactions	The unified description of the weak interactions and electromagnetism, developed between 1967 and 1970 by Sheldon Glashow, Steven Weinberg, and Abdus Salam
ejecta	Material that is ejected
matrix	A rectangular array of numbers or algebraic quantities representing a system of entities related in a systematic manner
cda	Centre de Donnees Astronomiques (Strasbourg, France)
semi-conductor	A material like silicon or germanium in which the valence band and the conduction band are separated by a small (forbidden) energy gap
bar	a unit of measure of atmospheric pressure
sedimentary rock	Rock formed from sediments.
curvature	The deviation of an object or of space or of spacetime from a flat form and therefore from the rules of geometry codified by Euclid
mundane astrology	That branch of astrology that deals with world events and universal trends rather than the individual.
unofficial flag	A flag that has (or had) not been formally adopted by the relevant authority, but is (or has been) exhibited by supporters or enthusiasts as representing a particular entity, institution or cause, as opposed to a design or type which is so authorized or for which there is (or has been) no authorized design – see ‘official flag 1)' (also ‘de facto 2)', ‘folk flag' and ‘institutional flags (unofficial)'.
osmium	Symbol:"Os" Atomic Number:"76" Atomic Mass: 190.20amu
marching flag	See ‘parade flag 1)’.
color excess	Difference between the observed color index of a star and the intrinsic color index corresponding to its spectral type
troposphere	the lower regions of a planetary atmosphere where convection keeps the gas mixed and maintains a steady increase of temperature with depth
tutorial on time	Meridian: The great circle passing through the celestial poles and the observer's zenith.
afro-american flag	See ‘Garvey colours'.
coriolis effect	The acceleration which a body in motion experiences when observed in a rotating frame
event chart	A horoscope drawn up according to the date, time and location of a particular happening, interpreted to gain insight into influences surrounding the event and an outlook for possible developments stemming from that event.
traps	Irregularities in the silicon crystal lattice which can absorb free charges created in the semiconductor by, for instance, the absorption of light
color charge	Color charge and strong charge are the same thing
bulletin	publication of America Mensa, Ltd., published 10 times per year
signal-to-noise ratio	The ratio of the amount of intelligible meaning in a signal to the amount of background noise
almagest	Arabic title for Ptolemy of Alexandria's Syntaxis, the writings in which he combined his own astronomical researches with those of others
gravity	A force of attraction, between two objects, that is proportional to the product of their masses and inversely proportional to the square of the distance between them.
nautical twilight	the time of morning or evening when the sun is 12° below the horizon
maltese cross	The heraldic term for a cross resembling four arrowheads, with straight-sided arms, eight outward facing points and generally (but not exclusively), inner points which meet at the centre – a cross of (the order of) St John of Jerusalem - but see ‘cross pattée’ in ‘appendix VIII’ (also ‘cross 2)’).
c4 plants	Plants that photosynthesize by the Hatch-Slack cycle
albedo feature	A dark or light marking on the surface of an object that may or may not be a geological or topographical feature.
nautical twilight	When the centre of the Sun is between 6° and 12° below the horizon; the marine horizon becomes invisible.
downpours	AIR POLLUTION
mho	Units of conductivity that are used in the study of electricity.
atmosphere	PROGNOSTIC CHART
eddington limit	In essence, radiation pressure must not exceed gravity
x-rays	Electromagnetic radiation to the far blue end of the spectrum, with wavelengths of about 0.01-10nm, and energies of 0.1-100 keV.
grand unification	(a) An attempt to produce a unification of all the forces of nature
first	Far-Infrared Space Telescope [LLM96]
structure	Mutual arrangement of atoms, molecules or ions that are packed together in a crystal lattice to form a crystal.
rom	Read Only Memory.
winding mode	A string configuration that wraps around a circular spatial dimension
equinox	(a) One of two points in the sky that represent where the Sun appears to cross the plane of the Earth's equator
velocity	A vector quantity whose magnitude is a body's speed and whose direction is the body's direction of motion.
dry adiabatically	LIGHTNING
air recognition device	See ‘fin flash' and ‘roundel 1)' (also ‘aircraft marking(s)').
brane	Any of the extended objects that arise in String Theory
promittor	The slower moving of two planets in aspect; the receiver of an aspect.
chromosomes	A long strand of the DNA double helix, with the strand wrapped around a series of protein cores.
focal point	Any point in a horoscope where several influences converge or disperse, such as the position of the squared planet in a T-square formation, the action point in a yod, the handle of a bucket, etc
electron redistribution	Redistribution occurs when electrons in a chemical bond are given up, received, or shared by two or more atoms
radiation damping	A decrease in the amplitude of an oscillation due to the emission of energy by radiation
royal society	English organization founded in the seventeenth century and dedicated to the advancement of science
imperial emblem	That emblem, now increasingly (but not entirely) obsolete, which represents an emperor – see ‘imperial arms’ (also ‘imperial standard(s) 1)’, ‘mon 2)’ and ‘royal standard(s)').
acceleration	Measure of how fast velocity is changing, so we can think of it as the change in velocity over change in time
explosive variables	see Cataclysmic Variables
hubble expansion	..
2 cvn star	see Spectrum Variable
eigenfunctions	The wave functions corresponding to the eigenvalues
great annihilator	The Great Annihilator is a powerful, high-energy x-ray source located near the center of the Milky Way Galaxy
circumpolar	Areas of the night sky which do not travel below the horizon over the course of a year, from a particular location on the Earth
celestial sphere	The projection of space onto the night sky, an imaginary hollow sphere of infinite radius surrounding the Earth but centred on the observer
mesopause	Boundary between the mesosphere and the thermosphere.
microbursts	TERRESTRIAL RADIATION
aspheric	An optical surface with departures in shape from a perfect sphere in order to cancel optical imperfections or aberrations
absorption of radiation	No medium transmits radiation without some energy loss
force	An entity that when applied to a mass causes it to accelerate
emphasized	See ‘garnished’.
royal greenwich observatory	RGO: Primary national 0bservatory in Great Britain, first sited at Greenwich in 1675, but in 1958 moved to Herstmonceux, Sussex
gaseous nebula	An H II region, a supernova remnant, or a planetary nebula
lumogen	A material used as a down-converter
light-emitting diode	LED -- A semiconductor diode, made from certain materials (e.g
storm surge	A rise above normal water level on the open coast due only to the action of wind stress on the water surface
space curvature	see Curvature
solar cycle	the approximately 11-year quasi-periodic variation in frequency or number of solar active events.
molecular geometry	Shape of a molecule, based on the relative positions of the atoms.
cynthion	Of or pertaining to the Moon
supernova remnant	an expanding shell of gas ejected at high speeds by a supernova explosion; the remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar material it sweeps up and shocks along the way; it is visible as a diffuse gaseous nebula usually with a shell-like structure and may resemble a "bubble"; an example of a supernova remnant is the Crab Nebula (M1) in Taurus
diurnal	From the Latin diurnus, daily
feed the owl	A “door charge” or “cover donation” to help the host of an event defray the cost, usually a minimal amount; requested at the discretion of the host
ritz combination principle	A principle discovered empirically before the advent of quantum mechanics which states that every spectral line of a given atom corresponds to the difference of some pair of energy levels.[H76]
blue horizontal-branch stars	Population II stars (B3-A0) in the galactic halo, characterized by strong, sharp hydrogen lines and large Balmer jump, and very weak lines of all other elements (see also HZ stars)
resonance	A state in which one orbiting object is subject to periodic gravitational perturbations by another.
anti-coincidence counter	A particle counter in which the circuit has been designed so as not to register the passage of an ionizing particle through more than one counting tube
electrodynamics	Study of the behavior of electromagnetic force in motion
zenith	the altitude is 90 degrees.
h and k lines	The two closely spaced lines of singly ionized calcium at 3968 and 3934 Å, respectively
confluence	DIFFRACTION
celestial equator	Projection of the Earth's equator as a line across the sky (so that to an observer actually on the equator, such a line would pass through the zenith)
w particle	(a) Very massive charged (+ or -) particle that conveys part of the weak force between leptons and hadrons
horizon	The boundary of the observable universe, defined by the distance that light can travel in the age of the universe.
forbidden energy gap	The unoccupiable interval of electron energy levels which forms in a crystalline substance (that is one having a periodic atomic formation) between the valence band (bound electrons) and the conduction band (free electrons)
coupling	An interaction between the components of a system
shockwave	In the field of aeronomy, name sometimes given to the solar side of the magnetopause.
banner of council	In English naval usage, now obsolete, a flag (often the Royal Standard) that was used prior to the invention of a signal code to summon a council of war aboard the flagship – but see note below (also ‘flagship’ and ‘signal flag’).
humidity	Atmospheric humidity is the amount of water vapour in the air
cytheran	Of or pertaining to the planet Venus
current density	Amount of charge passing through a unit area per unit time
planum	A high plain or plateau.
ptolemaic system	Odin was the king of the gods...
red giant	a star that becomes cooler, swells and glows with a red color
asymmetric drift	The negative of the mean V velocity of a stellar population
russell-vogt theorem	See Vogt-Russell theorem
declination	the latitude of a point on the celestial sphere using the equatorial coordinate system; declination divides the sky into 180 degrees (90 degrees north (+) and south (-) of the celestial equator)
green's theorem	An identity that connects line integrals and double integrals
energy spectrum	(In cosmic-ray studies, a plot of number of particles versus energy
chapman's equation	An equation expressing the velocity of a gas in terms of certain molecular constants
flat field	A picture taken of an even area to get rid of differences in an image from a CCD
lead	A lead is an elongated area of open water inside the sea-ice pack
span	Space Physics Analysis Network [LLM96]
bar	equals 0.987 atmosphere = 1.02 kg/cm2= 100 kilopascal = 14.5 lbs/inch2
lagrange points	Lagrange showed that three bodies can lie at the apexes of an equilateral triangle which rotates in its plane; if one of the bodies is sufficiently massive compared with the other two, then the triangular configuration is apparently stable (such bodies are sometimes referred to as Trojans); the leading apex of the triangle is known as the leading Lagrange point or L4; the trailing apex is the trailing Lagrange point or L5
trough	CYCLONE
electrostatic unit	A unit of charge defined as the charge which exerts a force of 1 dyne on a charge of equal magnitude at a distance of 1 cm
fortuna	From the Latin fortuna, fortune
inversion layer	a very thin layer of electrons trapped on an interface between a semiconductor and an insulator, or between two different semiconductors
absorptivity	Symbol: The ratio of the radiant or luminous flux absorbed by a body or material to the incident flux
vessel flag	In US army usage, now increasingly obsolete, a term for the special flag or pennant of an army unit, or of a type of command, flown by that unit or commander only when operating aboard a vessel – but see ‘boat flag 2)’ and note below.
astronomical unit	A measure of distance equal to the average distance between the Earth and the Sun
penumbra	The portion of a shadow in which only part of the light source is covered by the shadow-making body.
intercepted sign	A sign that does not appear on a house cusp but is wholly contained within a house.
station pressure	SEA MILE
eccentricity	the eccentricity of an ellipse (planetary orbit) is the ratio of the distance between the foci and the major axis
hardness	Hardness is a measure of how easily you can scratch a substance
aperture efficiency	The ratio of the effective aperture of the antenna, A, to its geometric aperture, Ag = d2 / 4
field of view	The patch of sky or of any image scene which can be seen by an optical system or by one picture element (pixel) of a detector system
ssb	Single Side Band [LLM96]
coordination	The number of anions surrounding a cation (or vice versa) in a stable ionic structure
chrysotile	Also called white asbestos, it is less friable (and therefore less likely to be inhaled) than the other types; it is the type most often used industrially
canis majoris	see Sirius
psychrometer	DRY LINE
achromatic color	A color that has no hue; i.e
r crb stars	Hydrogen-deficient C-type stars
arabian parts	Developed during the Middle Ages in Arabia, each part derived from three points in a horoscope, indicates a sensitive point that relates the three factors involved.
intensity	The amount, degree, or quantity of energy passing through a point per unit time
hylegiacal place	Synonymous with aphetic places
fertile signs	See fertility.
temporal houses	House two, six and ten, ruled by earth signs; symbolic of the material aspects life
ionized hydrogen	A hydrogen atom that has lost its electron
metar	ICE FOG
greenhouse gas	A greenhouse gas is a gas that has an impact on the radiative properties of the atmosphere by its ability to absorb radiation in specific infrared wavelengths, leading to the greenhouse effect
ion	an atom that has lost or gained one or more electrons and has become electrically charged as a result.
catastrophism	An early scientific school which held that most features of nature formed in sudden events, or catastrophes, instead of by slow processes.
new style	used to designate the
observation	CLEAR AIR TURBULENCE
affinity	A mutual attraction or innate congeniality.
solstice	The date when the Sun reaches maximum distance from the celestial equator (occurs twice annually).
band spectrum	A spectrum that appears as a number of bands of emitted or absorbed radiation
atomic second	see Second; Systeme International [S92]
coherence	Situation when electromagnetic waves are in-phase ("wiggle" up and down together)
valence	Valence is a measure of how much an atom wants to form compounds with other elements
light-year	the distance a beam of light in a vacuum travels in one year, about 5.88 trillion miles.
interstellar lines	Sharp, distinct absorption lines superposed on stellar spectra, produced by the interstellar gas located between the source and the observer
sea	A large, iron-rich basalt plain on the lunar surface
adorned	1) See ‘garnished'
vibration number	Whole number describing the energy in the uniform vibrational motion of a string; the energy in its overall motion as opposed to that associated with changes in its shape
war ensign	See ‘naval ensign’ listed under ‘ensign’ (also ‘s').
altitude	The height in degrees than an object is above the horizon an a given location
regge trajectory	Derived from S-matrix theory, the Regge Trajectories were theoretical plots that attempted to account for the position of elementary particle resonances
kirkwood gaps	Regions in the asteroid zone which have been swept clear of asteroids by the perturbing effects of Jupiter
background count	Unwanted counts due to background noise that must be subtracted from an observed number of counts in an experiment where atomic or nuclear particles coming from a source are being enumerated
streamline	(a) A line following the direction of the fluid in laminar or streamline flow
band head	The conspicuous sharp boundary which usually occurs at the head of a molecular band and which fades gradually toward either longer or shorter wavelengths, depending on the quadratic relation between frequency and rotational quantum number
scale invariance	S physical system is said to exhibit scale-invariance if its appearance remains unchanged (in a statistical sense, and to within simple readjustments of the units of measurements) by a coarse-graining operation
arc minute	There are 60 minutes (denoted as 60') of arc in 1 degree
simulations	In science, simulations of physical systems with a computer
reflection	The change in direction of light waves or sound waves as they bounce off a surface.
thermal equilibrium	(a) A state in which there is no net flow of heat
lysocline	The lysocline is the depth above which the rate of dissolution of CaCO3 is very low
thermal equilibrium	A balance between the input and outflow of heat in a system.
quantum cosmology	(a) The study of the Planck era
spherical space	A three-dimensional space whose geometry resembles that of the surface of a sphere and is said to have positive curvature
metar	SNOW GARLAND
radiant	A point in the sky from which meteors in a meteor shower seem to originate.
blue edge	(of the RR Lyrae instability strip) The curve on the H-R diagram that is traced out by the maximum temperature at which a stellar model is unstable against small-amplitude pulsations as the luminosity is varied
subsonic	Describing a speed that is less than the speed of sound in the medium concerned
collisionless damping	The tendency of weakly interacting (collisionless) matter to smooth out gravitational perturbations by freely streaming from overdense to underdense regions
eprom	Erasable Programmable Read Only Memory A small silicon chip containing thousands of individual locations which can be set to either a low or a high voltage level; a 0 or a 1
mev	one million electron volts.
tin	Symbol:"Sn" Atomic Number:"50" Atomic Mass: 118.69amu
lossy	Subject to absorption of light
kelvin	0 Kelvin is absolute zero; water melts at 273 K; water boils at 373 K; developed by William Thomson
laplacian plane	For planets see Invariable Plane; for a system of satellites, the fixed plane relative to which the vector sum of the disturbing forces has no orthogonal component
r galaxy	In the Yerkes9 1974 system, a system showing rotational symmetry, without clearly marked spiral or elliptical structure (formerly called D galaxy)
amorphous	Denoting a solid that has no crystalline structure; i.e
tai	International Atomic Time [LLM96]
lunar node	See Nodes
interloc	A free newsletter published for interested and involved Mensans, reporting on the business of Mensa, the AMC and the national office
tt&c	Tracking, Telemetry and Control, a term used to refer to the ground stations used in the day-to-day monitoring and control of a satellite
unification	The idea that the four forces of nature are just different manifestations of one basic superforce; the properties of the superforce can be realized only at phenomenally high temperatures or energies.
julian date	The interval of time in days (and fraction of a day) since Greenwich noon on Jan
achernar	A subgiant of spectral type B5, about 35 pc distant
solar cycle	22-year cycle of solar activity.
chemical forces	Chemical forces act on the bonds of molecules and atoms
mega-	A prefix meaning 106
tessera	tile; terrain formed of polygonal pattern
celestial equator	An imaginary line that extents from out the Earth's equator and is projected onto the sky
slew	The relatively rapid motion of a telescope (under computer control) as it moves to point at a new position in the sky
balkan cross	An often used, but incorrect, translation (balken meaning a "balk, "bar" or "beam" of wood) of the German term balkenkreuz - see ‘balkenkreuz'.
weathering	The action of elements in altering the colour, texture, composition, or form of exposed objects on the surface of a planet of Moon.
coordination number	Number of atoms closest to any given ion in a crystal
solar wind	stream of charged particles emitted from the sun.
milli-	A prefix meaning 10-3
solar wind	Led to a number of major discoveries about the Sun
semi-minor axis	Half the length of the minor axis of an ellipse; a standard element used to describe an elliptical orbit
galilean transformation	The non-relativistic method of relating observations from one frame of reference to another
amplitude	The size of a wave from the top of a wave crest to its midpoint.
jieqi	Name of a minor solar term of the Chinese calendar
cabled cross	See ‘roped cross'.
nadir	The point with a negative ninety degree inclination in relation to the observer, or the point directly beneath their feet
metonic period	Odin was the king of the gods...
aphelion	The farthest point of an elliptical orbit from the Sun
planetary geology	The study of the processes and history associated with the solid, rocky objects of the solar system.
glueball	(a) Hypothesized form of matter consisting entirely of gluons
equinox	the two points at which the sun crosses the celestial equator; the spring equinox is about March 21, and the autumnal equinox is about September 22
natural	See ‘proper’.
false color	The use of colors, instead of shades of grey, on a computer image display screen to represent different brightness levels and highlight very small differences in a dramatic way
quantum theory	(a) A theory which seeks to explain that the action of forces is a result of the exchange of sub-atomic particles
induction	System of reasoning in which the conclusion, though implied by the premises and consistent with them, does not necessarily follow from them
fluctus	flow terrain.
matter-to-antimatter ratio	The ratio of mass in particles to mass in antiparticles
strong force symmetry	Gauge symmetry underlying the strong force, associated with invariance of a physical system under shifts in the color charges of quarks
force	That which can change the momentum of a body
ground state	The minimum energy state of an atom that is achieved when all of its electrons have the lowest possible energy and therefore are as close to the nucleus as possible.
higher-dimensional supergravity	Class of supergravity theories in more than four spacetime dimensions
superforce	The force which is dominant in GUT (Grand Unified Theories) It combines the electroweak force with the strong nuclear force
occulation	the blockage of light by the intervention of another object; a planet can occult (block) the light from a distant star
landspout	WATER VAPOR (H2O)
atmospheric dispersion corrector	An optical device usually comprising two thin prisms which can rotate to compensate for the elongation of a star image caused by the wavelength dependence of the refractive index of air
hail	FUJITA-PEARSON SCALE
'x' cross	See ‘saltire' and ‘St
hubble's constant	The value that relates the distance of an object to speed of recession in Hubble's Law
starch	A long chain of carbohydrates formed in plants
arc second	There are 60 seconds (denoted 60") of arc in one minute of arc.
stone meteorite	A meteorite that resembles a terrestrial rock and is composed of similar materials.
ceramic	Inorganic non-metallic materials
umbra	From the Latin for shade, it is the shadow area defining a total eclipse
cotidal line	A line on chart passing through all points where High Water occurs at the same time.
compton wavelength	(a) The wavelength of a photon containing the rest energy of a particular particle
adaptive optics	A way of correcting for atmospheric interference using a bright reference star to measure variations and a deformable mirror to correct for them
liquid	A high-density form of matter in which the atoms or molecules can move freely and take the shape of the container
arc angle	The measurement of the angle between two objects or two parts of the same object.
heliosphere	Region in space that undergoes the influence of the solar wind
spörer's law of zones	The equatorward drift of average sunspot latitudes
ph	Measures the acidity of a solution
cfc	Chlorofluorocarbon
bromine	A deep red, moderately reactive element belonging to the halogens
electron conduction	A process in astrophysics occurring in highly ionized stellar interiors where the density is high, whereby the bulk of the energy is transported by "hot" electrons moving in one direction and cooler electrons in the other
spectroscopy	The study of stellar spectra in order to determine the chemical composition of stars.
supersymmetric standard model	Generalization of the standard model of particle physics to incorporate supersymmetry
eclipse	An event in which the shadow of one body falls on another body.
luminosity	The total amount of energy emitted per second by an astronomical source.
arcsecond	One sixtieth of an arcminute, or 1/3600 of a degree
altair	( Aql) (a) A bright (mv = 0.78) A7 V star about 4.8 pc distant
nonile	A ninth harmonic aspect based on division of 360° by 9 (40°)
rima	fissure.
tropical wave	ECHO
habited	A heraldic term used to describe the customary clothing (the "habit") of a monk or friar – habillé – but see ‘vested' (also ‘clad').
resolution	The smallest angle that can be discerned with an optical system; for example, the eye can resolve about 2 minutes of arc.
eddington's standard model	A stellar model in which energy is transported by radiation throughout the whole star and the ratio of the radiation pressure to the gas pressure is assumed to be constant
hour circle	(i) A great circle passing through an object and the celestial poles
intrinsic brightness	The amount of light an object actually emits, as opposed to how bright the object looks from Earth
thorium	Symbol:"Th" Atomic Number:"90" Atomic Mass: 231.04amu
arctic air masses	ARCTIC SEA SMOKE
aurigae stars	In general, binaries with a K supergiant primary and a main-sequence secondary
tektite	Spherule of molten rock ejected from an impact crater and then cooled rapidly to produce glass.
cluster of galaxies	A relatively close grouping of galaxies, often with some members coorbiting or interacting with each other.
markovian process	a random process in which the probability of performing a transition to a certain state at a given time depends solely on the state in which the system is found at this time
brightness	(a) Refers to the amount of light coming from an object
atb	Acronym for After The Bang; usually used in reference to time elapsed since the big bang
metar	SQUALL LINE
fsm	Fold, Spindle, and Mutilate (aka the Folding Party): volunteers gather each month to fold, staple and label the monthly newsletter in preparation for bulk mailing
dwss	Defense Weather Satellite System
milky way	A broad band of light that looks like a trail of spilled milk in the night sky
higgsino	The superpartner of the Higgs boson
k	Kilo, a multiplier, x103 from the Greek "khilioi" (thousand)
erosion	The wearing away of a surface by natural process such as lava flow, bombardment, wind, water, or other mechanisms.
inverse p cygni profile	A profile in which the emission is on the violet side of the absorption
electronegativity	Measure of a substance's ability to attract electrons.
latitude	TROPOPAUSE
serial register	The final (horizontal) row of a CCD in which the controlling electrodes are arranged at right angles to those on the rest of the CCD
orbital family	a group of asteroids that follows the same relative orbital path, velocity, and is usually seen close together; they are thought to have once been one asteroid that was broken apart due to a collision in the past
negatively curved geometry	A geometry in which parallel lines diverge; sometimes called a hyperbolic geometry.
coarse-graining	an operation implementing some form of spatial averaging which smoothes out relatively small length-scale configurational structure while preserving the larger length-scale structure
heisenberg uncertainty principle	A fundamental limitation to the precision of physical measurements
eoli	Earth Observation Link (catalogue)
aerobic	A process that requires the presence of oxygen; e.g., respiration.
squall	SOLAR DAY
gravitational instability	The process by which fluctuations in an infinite medium of size greater than a certain length scale (the Jeans length) grow by self-gravitation
orbit	The path a heavenly body follows as it travels around another stellar body.
cosmology	a branch of astronomy concerned with the study of the origin and evolution of the universe.
storm	ISOPLETH
mineral streak	Minerals are often ground down into a power
radiative equilibrium	In a star, represents an even process by which energy (heat) is transferred from the core to the outer surface without affecting the overall stability of the star
dodecahedral crystal	A crystal that has twelve sides
haab	name of the 365-day-year employed by the Mayans
ghost	A faint image near the image required, caused by radiation that has taken a different path
celestial ephemeris pole	The reference pole for nutation and polar motion; the axis of figure for the mean surface of a model Earth in which the free motion has zero amplitude
knot	A division of the log line by which the ship's speed is measured
fess-point	See ‘honour point 2)’.
beat cepheids	Dwarf Cepheids in which two or more almost identical periods exist which cause periodic amplitude fluctuations in their light curves
halbrundschild	The German term for a round-bottomed shield - see 'Spanish-style shield'.
equatorward	WEST VIRGINIA HIGH
bootis	see Arcturus
electron-phonon scattering	Electron scattering by ions oscillating about equilibrium positions which form a perfect lattice
lagrangian points	Points in a two body gravity system of large objects (such as the Sun and Earth) where small objects can orbit the primary body and remain almost stationary relative to the secondary body.
overcast	UNITED STATES WEATHER BUREAU
soluble	Soluble is the ability of a substance to dissolve in another substance
calcium-k	Calcium-K is a specific wavelength (roughly 393.3 nanometres) of ultraviolet light, emitted by calcium atoms that are missing one electron
tetragonal crystal	A crystal that has a basic cube shape but is stretched out
epoch	A particular period of history, or a reference point in time.
multiverse	Hypothetical enlargement of the cosmos in which our Universe is but one of an enormous number of separate and distinct Universes
enclaves	IEM covers a very large area
eri	A fourth-magnitude K2 V star 3.30 pc distant
yy gem	See Castor
impurity and conduction	IBC A form of infrared array detector which replaces the photoconductor and provides higher performance
supra-thermal proton bremsstrahlung	Ordinary electron-proton bremsstrahlung viewed from the rest frame of the electron rather than the proton; in other words, the electron is at rest and the heavy particle (proton) is moving
perturbation	Small deviances in the location of a star, visible through large telescopes.
resonance	A close, or simple-number, relationship between periodicities in two phenomena
resonance particles	(a) Hadronic particles which exist for only a very brief time (10-23 seconds) before decaying into hadrons
eccentricity	The ratio of the length between the center and the focus to the semimajor axis of an ellipse.
pumice	a light vesicular form of volcanic glass with a high silica content; it is usually light in color and will float on water.
aerolite	A stony meteorite, composed primarily of silicates
mev	One million (106) electron volts
gravity	the attractive force of a body
metric system	The system of measurement used in almost all of science
soe	Sequence of Events.
great circle	A great circle is an imaginary circle on the surface of a sphere whose plane passes through the center of the sphere.
tutorial on time	Equatorial Co-ordinates: A system of celestial co-ordinates that uses the celestial equator as the reference plane and the First Point of Aries as the reference direction
jack pin	See ‘belaying pin’.
ratio	The relative size of two quantities expressed as the quotient of one divided by the other; the ratio of a to b is written as a:b or a/b.
emission measure	The product of the square of the electron density times the linear size of the emitting region (in parsecs)
racing flag	1) A flag flown from a yacht that is taking part in a race, and struck if it withdraws or when it crosses the finish line (see also ‘preparatory flag’, ‘prize flag’, ‘race signals’ and ‘strike’)
differential rotation	A rotational property of gaseous objects, where the equatorial regions rotate at a faster rate than the polar regions.
mds	Measurement Data Set, a defined data entity within a product.
carina ob 2	A rich association of OB stars near Carinae
cohomology	A branch of mathematics concerned with the patching together of spaces
holmium	Symbol:"Ho" Atomic Number:"67" Atomic Mass: 164.93amu
cap of liberty	An ancient symbol in the form of a soft red cap which, as a consequence of having been adopted by various revolutionary movements during the 18th century, has come to be regarded as a symbol of resistance against monarchical or imperialist oppression – a liberty, Phrygian or Scythian cap.
debased	See ‘reversed 2)’.
designating flag	See ‘headquarters flag 2)’.
limb correction	Correction that must be made to the distance between the center of mass of the Moon and its limb
radian	(a) A measure of angular distance; 2 radians equals 360 degrees
corrector plate	This is a lens plate that fits on the front of Schmidt-Cassegrain and Maksutov-Cassegrain telescopes to correct optical aberrations.
ice jam	FLOOD
unrep flag	See ‘battle flag 2)’.
tropic of capricorn	These names come from the constellations which the Sun entered at the solstices when the names were first applied more than 2,000 years ago
saturated	CONVERGENCE
biosphere	GEOSTATIONARY SATELLITE
superconducting super collider	SSC A proposed accelerator of great size and high energy
zodiacal light	a faint, diffuse, cone-shaped glow seen during morning or evening twilight that appears to extend up from the vicinity of the Sun along the ecliptic; it is best seen in spring and autumn when the zodiac makes a steep angle to the horizon; caused by sunlight scattered from dust in orbit about the Sun, the zodiacal light is so faint that it can only be seen from very dark skies
admiralty flag	1) Specifically in UK usage see ‘anchor flag' and its following note (also ‘fouled anchor')
quantum chromodynamics	QCD(a) The quantum field theory describing the interactions of quarks through the strong "color" field (whose quanta are gluons)
invariable plane	The plane through the center of mass of the solar system perpendicular to the angular momentum vector of the solar system
semimajor axis	one-half of the longest dimension of an ellipse.
vertical multi-stripe	See ‘multi-stripe’.
epicycle	(a) Circular orbit of a body round a point that is itself in a circular orbit round a parent body
cryostat	Also dewar
metar	BLUE NORTHER
undae	dunes (literally 'waves')
kao	Kuiper Airborne Observatory
gmes	Global Monitoring of Environment and Security
heliograph	Device for recording the positions of SUNSPOTS
collisional process	An event involving a collision of objects; for example, the excitation of a hydrogen atom when it is hit by an electron.
constellation	an area of sky; originally a grouping of stars in the sky to form some kind of pattern; there are 88 officially recognised constellations
redshift	A Doppler shift of spectral features toward longer wavelengths, indicating recession of the source.
godae	Global Ocean Data Assimilation Experiment
charmonium	A bound state consisting of a charmed quark and a charmed antiquark
eddy	A circular movement of water usually formed, where currents pass obstructions, between two adjacent currents flowing counter to each other, or along the edge of a permanent current.
heterotic e-string theory	Heterotic E8 × E8 string theory One of the five superstring theories; involves closed strings whose right-moving vibrations resemble those of the Type II string and whose left-moving vibrations involve those of the bosonic string
electroweak unification energy	the energy (around 100 GeV) above which the distinction between the electromagnetic force and the weak force disappears
clouds	SNOW FLURRY/FLURRIES
eccentricity	(a) In astronomy, the extent to which an elliptical orbit departs from a circular one
critical point	a point in a phase diagram identifying conditions in which the correlation length associated with some appropriate set of microscopic variables is, in principle, as large as the physical system
natant	See ‘naiant’ in appendix V.
constituents	Any objects that are bound together to make larger objects
ergoregion	That part of space in which no physical object can remain at rest with respect to an observer at infinity; the dragging of inertial frames is so extreme that all timelike world lines rotate with the star
masoned	A heraldic term used to describe the lines formed by masonry blocks in a building.
image tube	An electronic camera in which electrons, emitted from a photocathode surface exposed to light, are focused electronically onto a phosphor or photographic plate
isotopic spin	A concept introduced by Heisenberg in 1932 to describe the charge independence of the strong nuclear force
sdb	Subdwarf B-type stars with very broad and shallow Balmer lines; fewer lines of the Balmer series are visible than for normal dwarfs
mons	mountain (plural: montes)
cell membrane	A structure, formed from bilayers of lipids, that seperates the inside of the cell from the outside, or seperates one part of a cell from another.
conservation of energy	(a) The principle that the total energy of a closed system never changes, that energy is only converted from one form to another
umbra	The portion of a shadow cone in which none of the light from an extended light source (ignoring refraction) can be observed
harmonic prediction	In tidal terminology, the method of predicting tides and tidal currents by combining the harmonic constituents into a single curve
quantum theory	and is one of the most important physicists of the twentieth century.
nova	a star that flares up to several times its original brightness for some time before returning to its original state.
ph	pH is a measure of acidity
quarterly	A heraldic term for when the field of a shield, flag or banner of arms is divided horizontally and vertically into four quarters - but see ‘quartered 1)' (also ‘banner of arms', ‘canton 3)', ‘quarter', ‘quarter the arms', ‘quartering' and ‘shield 1)').
baryon-to-photon ratio	(See photon-to-baryon ratio.) [LB90]
primary body	The body that is being orbited
hurricane	TROPICAL PREDICTION CENTER (TPC)
high-luminosity early type objects	A collective designation for some early type stars with very peculiar spectra, like S Dor and P Cyg
random walk	If a point experiences successive displacements such that each displacement is in a random direction and of a length also governed by a frequency distribution, then the point is said to experience a random walk
second parameter	The color of a globular cluster's horizontal branch is determined largely by its metallicity: all other things being equal, the more metal-poor a cluster, the bluer its horizontal branch
barnard's satellite	also known as Amalthea.
galaxy	is a peripheral member of the Virgo Supercluster, centered around a giant elliptical galaxy M87
knight banneret	See ‘banneret 2)’.
speed of light	often considered a constant (3.0 x 10^8 m/s), the speed that light travels depends on the medium through which it travels
golay cell	A gas bulb used to detect infrared radiation
arcminute	1/60 of a degree, shown by the symbol '.
pseudocrater	a generally circular crater produced by a phreatic eruption resulting from emplacement of a lava flow over wet ground.
uprooted	See ‘eradicated’.
albedo feature	a dark or light marking on the surface of an object that may not be a geological or topographical feature
prime vertical	The great circle that rises vertically from the east point of the horizon and passes through Earth's zenith and nadir.
arc-minute	Angular measure, 1/60 of a degree.
thunderstorm	TRACE
quadrant	An instrument, based on a quarter of a circle, employed to measure the altitude above the horizon of astronomical bodies
world line	(a) In space-time, the history of a particle is represented by a world-line
sspm	Solid State Photomultiplier [LLM96]
vidicon	General name for the class of vacuum tube imaging devices which employ a scanning electron beam to read out the image
isochrones	Time-constant loci
salient	See ‘appendix V’.
radiant energy	Energy which is transmitted away from its source, for example, energy that is emitted when electrons transition down from one level to another.
qa	Quality Assurance
terminator	The boundary between day and night regions of the moon's, or a planet's, disc.
intervalometer	A camera accessory that measures time intervals, often used to create time-lapse sequences.
transition zone	Region of the solar atmosphere, between approximately 3000 kilometers and forty thousand kilometers, where the temperature increases from 10,000 degrees to more than one million degrees.
integrating detector	Any imaging device, like a photographic emulsion or CCD, which can build up more signal and contrast by a longer exposure to light or other electromagnetic energy
nadir	The zenith and nadir are the extremities of a diameter of the celestial sphere through the observer and the common center of the Earth and the celestial sphere
zinc	Symbol:"Zn" Atomic Number:"30" Atomic Mass: 65.38amu
altitude	uniquely define an objects position in the local sky.
apheta	, also Alpheta Literally, the giver of life; A well aspected benefic that occupies an aphetic (hylegiacal) place in the horoscope, said to have life-preserving qualities
s-factor	A nuclear cross-section factor measured in keV-barns
ramsauer effect	An anomalously large mean free path for low-energy electrons
solar maximum	The period when the activity of the Sun and the number of sunspots are highest.
radiation	(1) Any electromagnetic waves or atomic particles that transmit energy across space; (2) one of three modes of heat (energy) transmission through stars or planets from warm regions to cool regions.
erg	a cgs unit of energy equal to work done by a force of 1 dyne acting over a distance of 1 cm
zepto-	Symbol: z A prefix denoting 10-21
trojan	an object orbiting in the Lagrange points of another (larger) object
broken symmetry	In cosmology and particle physics, a state in which traces of an earlier symmetry may be discerned
magnetopause	The region in earth's ionosphere where the magnetosphere meets the Solar Wind
carbonate	a compound containing carbon and oxygen (e.g
wave function	(a) The mathematical object in quantum theory which determines probabilities of different results of experiments
cosmological constant problem	The puzzle of why the cosmological constant has a value which is either zero, or in any case roughly 120 orders of magnitude or more smaller than the value that particle theorists would expect
meridian	The imaginary line that runs from the horizon to the zenith while looking directly south
cosmology	A branch of science that deals with studying the origin, structure, and nature of the universe.
frequency	Describes the number of wave crests passing by a fixed point in a given time period (usually one second)
stationary state	one that is not changing with time; a sphere spinning at a constant rate is stationary because it looks identical at any given instant
elevation	The angle in degrees above the horizon toward the zenith or overhead point
undae	dunes (literally 'waves').
naval jack	Flown at the bow of a warship, often the appropriate national flag (or a variation of it), occasionally the same as the naval ensign, or sometimes a completely different design - the jack (see also ‘masthead pennant 1)’, ‘naval ensign’ under ‘ensign’, ‘jack staff' and ‘suit of flags’).
mach's principle	(a) The precept that the inertia of objects results not from their relationship to Newtonian absolute space, but to the rest of the mass and energy distributed throughout the Universe
current station	The geographic location at which current observations are conducted
vested	The heraldic term that is properly employed to describe the vestments of a bishop, archbishop or prince of the Church, but which is sometimes used for the habit of a monk or friar – but see ‘habited' (also ‘adorned 2)' and ‘clad').
diurnal inequality	The difference in height of the two high waters, or of the two low waters of each tidal day
signal band	The wavelength interval within which a feature (e.g., the 21-cm line) is measured (cf
elections	The 5 voting members of IEM’s Board are elected positions
avalanche	A process such as that in which a single ionization leads to a large number of ions
zenith	The point in the sky directly overhead.
bode's law	(a) A prescription for calculating planetary distances: the distance to the nth planet is 0.4 + (0.3)n Astronomical Units
deck flags	A term to describe the practice, now obsolete, of showing a display of flags along the sides of a ship as illustrated below – see ‘pavisade' and ‘streamer 2)' (also ‘ancient' and ‘postures').
bl lacertae	A highly variable object (the most rapid radio variable known, also an optically violent variable - mv = 12 to 15 mag - and an infrared source)
acausal initial conditions	Initial conditions that could not have been caused by any prior physical process
supercooling	(a) The process by which a substance is cooled below the temperature at which a phase transition should occur, such as water that has been cooled to below zero degrees Centigrade but that has not yet formed ice
terra	extensive land mass
rossby waves	Cyclonic convection waves in a rotating fluid
metal-poor	Having a low metallicity with respect to Solar
cerium	Symbol:"Ce" Atomic Number:"58" Atomic Mass: 140.12amu
manifold	(a) A mathematical concept used to describe the geometry of spacetime
pig*sig	Our monthly gathering at a local restaurant
granule	Granules are regions of the Sun where hot solar material comes to the solar surface
parallels	Circles in parallel planes to that of the equator defining north-south measurements, also called lines of latitude.
continuum	A set of points which form a line (one-dimensional continuum), a plane (two-dimensional continuum), etc
bacteria	The smallest type of living organisms.
radio source	A point or small portion of the sky giving stronger radio emission than the sky in its vicinity.
pole	end of an axis, or the point where an axis meets the surface of a planet (geographic); either end of a magnet and points where the magnetic forces originate (magnetic).
coma	Coma is a optical aberration, where stars at the edge of a field of view appear to broaden out into triangle or fan shapes, caused by an imperfection in the lens or mirror.
microwave radiation	(a) Radiation in the electromagnetic spectrum between infrared and radio waves
one-and-a-half armed cross	The term used in Eastern European heraldry – and a direct translation of the Polish Póltora krzyz – that describes a Latin cross which has a second horizontal arm projecting on one side only - usually the sinister (see also ‘cross 2)’, ‘cross of Lorraine’, ‘Latin cross’ in ‘appendix VIII’ and ‘two-and-a-half armed cross’).
horizon co-ordinates	The system of celestial co-ordinates in which the observer's horizon is the reference plane and the north point is the reference direction
crust	The outermost, solid layer of a planet, with composition distinct from the mantle and differentiated by a seismic discontinuity.
meridian	A line connecting all points are the same longitude on the surface of the Earth or on any other heavenly body.
subcritical	Describing an arrangement of fissile material that does not permit a sustained chain reaction because too many neutrons are absorbed without causing fission or otherwise lost
under the sun's beams	Within 17 degrees of the Sun
explorer	A US series of satellites, many of which remain in orbit round the Earth fulfilling scientific functions
meteoroid	A particle in space, generally smaller than a few meters across.
epicycle	In the Ptolemaic system, an epicycle is a smaller circular motion added to the larger orbital motion of the planet
heisenberg uncertainty principle	(a) States that the position and momentum of a particle can only be known to a certain level of precision
aerolite	A meteorite which is stoney.
atto-	A prefix meaning 10-18
qcd	Quantum Chromodynamics
equilibrium	A steady state which will not change unless an external force or event disrupts the stability.
lumen	Symbol: lm -- The SI unit of luminous flux, equal to the luminous flux emitted by a point source of one candela in a solid angle of one steradian
metar	SNOW
orthorhombic crystal	This crystal forms a prism that has three edges at ninety-degree angles.
basalt	A type of volcanic rock, often formed in lava flows, which is common on the Moon and terrestrial planets.
event	a point in space-time, specified by its time and place
albedo	Describes the fraction of sunlight reflected by a surface; albedo = 0 means no reflection at all (a perfectly black surface); albedo = 1 means all light is reflected (a perfectly white surface).
ecliptic plane	The ecliptic plane is the plane defined by the earth's orbit, which is inclined by 23.5 degrees from the equatorial plane due to the tilt of the earth's spin axis
apollo space program	Successful US lunar exploration program in which the Apollo spacecraft 1 to 6 were unmanned; 7 to 10 were manned but did not land; and 11, 12 and 14 to 17 landed and returned safely
kev	one thousand electron volts
spectrum	The range of colors that make up visible white light
star	Luminous gaseous heavenly body, whose energy is normally provided by nuclear fusion reactions taking place in its core
histogram display	This is the graph that appears on a camera's LCD screen plotting pixel brightness along the horizontal axis, and the number of pixels at each brightness value along the vertical axis.
photon	a discrete quantity of electromagnetic energy
geodetic datum	A set of parameters specifying the reference surface or the reference coordinate system used for geodetic control in the calculation of coordinates of points on the Earth
quadrature of moon	An elongation of 90° usually specified as east or west in accordance with the direction of the body from the Sun
potassium	Symbol:"K" Atomic Number:"19" Atomic Mass: 39.10amu
gaia hypothesis	named for the Greek Earth goddess Gaea, holds that the Earth as a whole should be regarded as a living organism and that biological processes stabilize the environment
ceti	A G8 Vp star about 3.6 pc distant
aphelion	The point in a planetary orbit that is at the greatest distance from the Sun
reniform habit	A shape of a large crystal which has the arrangement of several small rounded balls stuck together
celestial sphere	The conceptualization of the infinite heavens as a sphere revolving around Earth, based upon the part of the skies visible from a point on Earth.
cosmic censorship	(a) Theory that the hidden interior within all event horizons is the same and is always, necessarily, hidden
equinox	From the Latin aequinoctium, equal night; occurs when the center of the Sun is directly over Earth's equator
spot	Satellite Probatoire d'Observation de Ia Terre [LLM96]
national pennant	See ‘wimpel 1)'.
quadruplicity	One of the three qualitative groups (cardinal, fixed, mutable) in which each of the four member signs share a common mode of expression.
vambraced	The heraldic term used when an arm only is shown clad in armour - but see ‘harnysed’ (also ‘armoured’ and ‘embowed’).
tutorial on time	Solstice: Literally "sun still"
analemma	Observed every day from the same location at the same time, the Sun follows a figure-of-eight path through the sky
comatic aberration	An optical defect in a lens, which means light rays that enter the edge of the lens at an angle converge so as not to be brought to a sharp focus
inertial mass	The mass of an object as measured by the property of inertia
ascending node	In the orbit of a Solar-System body, the point where the body crosses the ecliptic from south to north: for a star, out of the plane of the sky toward the observer
naissant	The heraldic term for a charge or figure emerging from the side of a shield, banner of arms or a flag, or the centre of an ordinary – nascent – but see ‘issuant’ with following note (also ‘banner of arms' and ‘ordinary’).
amplitude	The maximum deviation of a wave above or below zero point.
jet stream	JET STREAM
fried parameter	A measure of the scale of the turbulence in the atmosphere
ballik-ramsay bands	Spectral bands of the C2 radical in the near infrared (0-0 at 1.7625 µ)
scientific notation	The style of writing large and small numbers using powers of ten.
iue	International Ultraviolet Explorer
solar wind	Magnitude The degree of brightness of a star or other object in the sky according to a scale on which the brightest star has a magnitude -1.4 and the faintest visible star has magnitude 6
kalends	name of the first day of a month of the Roman calendar
union standard	In British military usage, a term for one of three such standards each carried by the Life Guards and the Blues and Royals - the Household cavalry - and the equivalent of a normal cavalry guidon or infantry colour (see also 'colour 2)', 'colours 2)' and ‘guidon 2)’ and ‘sovereign's standard').
energy distribution	The amount of energy radiated at each range of wavelengths
c-s stars	Group characteristics are: strong bands of CN, outstandingly strong absorption near the Na D lines, usually sufficient structure in the 6400-6500 Å region to suggest ZrO
zodiacal light	A faint glow that extends away from the Sun in the ecliptic plane of the sky, visible to the naked eye in the western sky shortly after sunset or in the eastern sky shortly before sunrise
westerlies	COLD WAVE
observations	SEMI-PERMANENT PRESSURE SYSTEMS
vortex	In a planar spin model a vortex is a pattern of spins in which the spin direction rotates by 360 degrees along any path which surrounds the centre of the vortex
carbonate compensation	Carbonate compensation is a negative feedback between the oceanic carbon cycle and the underlying sediments that tends to reduce the variations in the alkalinity in the ocean and thus to stabilise the atmospheric CO2 over long timescales
mendelevium	Symbol:"Md" Atomic Number:"101" Atomic Mass: (258)amu
ebb current	The horizontal movement of water associated with the falling tide
branching ratio	Ratio between the numbers of atoms starting from a given initial state which undergo two different types of transitions, perhaps, or between different bound states
facula	A region or spot that is brighter than the rest of the solar surface.
altitude	the angular distance of an object above or below the horizon
millibar	1/1000 of a bar
electronuclear force	Single fundamental force thought to have functioned in the very early Universe and to have combined the attributes thereafter parceled out to the electromagnetic and the strong and weak nuclear forces
anareta	From the Greek, literally destroyer
scintillation	Twinkling of stars
maxwell's theory	Theory uniting electricity and magnetism, based on the concept of the electromagnetic field, devised by Maxwell in the 1880s; shows that visible light is an example of an electromagnetic wave
planet	Apastron The point of greatest separation of two stars, such as in a binary star system.
equilibrium	When the reactants and products are in a constant ratio
sense	One of two opposite directions describable by the motion of a point, line, or surface
obliquity of the ecliptic	The angle between the plane of the ecliptic and the plane of the equator
m magnitude	The magnitude derived from observations at an infrared wavelength of 5 microns
hertzsprung gap	A gap (from about A0 to F5) in the horizontal branch of the H-R diagram (see instability strip)
carrier boson	A particle that carries one of the fundamental forces between other interacting particles
base	Substance which gives off hydroxide ions (OH-) in solution.
anaretic place	the final degree (between 29° and 30°) of any sign, also called the degree of fate
mini black holes	In a chaotic early Universe, black holes may form at eras as early as the Planck time
yacht officer's flags	See ‘officer’s flags’.
spiral galaxy	They are classified as type S0 (or type SB0 if they also have a central bar).
maclaurin spheroid	A form which a homogeneous self-gravitating mass can take when in a state of uniform rotation
prokaryote	Cell that contains a single long strand of DNA but no nucleus
radiant	a point in the sky from which meteors in a meteor shower seem to originate.
ellipticity	A quantitative measure of the shape of a galaxy
apastron	The point of greatest separation of two stars, such as in a binary star system.
sofia	Stratospheric Observatory for Far-Infrared Astronomy
coherent scattering	A scattering process that leaves atoms in the same energy state after the scattered photon departs in a direction different from that of the incident photon
inflamed	The heraldic term used when a charge is shown with flames coming from it – ardent, enflamed or flamed – but see ‘incensed 1)’ (also ‘flamant').
orbit	An orbit is the path one object takes when it spins around another object
idcs	International Data Collection System
great looped nebula	See 30 Doradus
drake equation	The statement that the fraction of stars harboring intelligent life equals the number of all stars times a sequence of fractions, such as the fraction of all stars having planets, the fraction of planets that are habitable, and so on
angular momentum	(a) The angular momentum of a system about a specified origin is the sum over all the particles in the system (or an integral over the different elements of the system if it is continuous) of the vector products of the radius vector joining each particle to the origin and the momentum of the particle
celestial sphere	The projection of space and the objects therein onto an imaginary sphere surrounding the Earth and centred on the observer.
zenith	Point on the celestial sphere directly above the observer's head.
rise of tide	The height of high water above datum
perihelion	the innermost point of a solar orbit
year	PREVAILING VISIBILITY
annual motion	The apparent motion of the celestial objects seen from a single location at the same time
boundary layer	A thin layer of fluid, such as the one next to a solid surface past which the fluid is moving
ccd	The resulting image is called an astrophotograph, and the person who made it an astrophotographer.
armillary sphere	Ancient Greek, Arabic and medieval alt-azimuth device, comprising a calibrated ring fixed in the meridian plane, within which a second concentric ring, also calibrated, was mobile around a vertical axis
order	An integer (m) associated with a given interference fringe or diffraction pattern
pptl	Processor Point Target Linearity
rf power	Radio-Frequencypower
color	Color is a measure of reflected wavelengths of light
wavelength	(a) The distance between adjacent peaks in a wave-train is the wavelength
riemannian geometry	Mathematical framework for describing curved shapes of any dimension
s band	A radiofrequency band at a wavelength of 11.1 cm
ecliptic	(1) The plane of the Earth's orbit and its projection in the sky as seen from Earth; (2) approximately, the plane of the solar system.
absolute zero	(a) The zero value of thermodynamic temperature; 0 kelvin or -273.15°C
great circle	A circle on the surface of a sphere that runs through two certain fix points and has the maximum diameter of all circles that exist running through these two points
aml	An abbreviation for "American Mensa, Ltd.," the official name of our society within the United States.
dual offset dish antenna	This type of satellite dish has two dishes, a larger receiving dish and a small dish facing the opposite direction that takes the signal and transfers it to the LNC
us executive order	See ‘executive order’.
absolute zero	The lowest possible temperature, -273.16 degrees C.
aphelion	The point in an orbit around the Sun at which an object is at its greatest distance from the Sun (Opposite of perihelion).
electoral cap	The term for a coronet (of varying design) now obsolete, that appeared above the arms of those German rulers who (until 1806) had the hereditary right to elect an emperor of the Holy Roman Empire, with a typical example being that above the Hanoverian inescutcheon on the royal standard of the UK from 1801 – 1816 (see also ‘coronet 2)’, ‘inescutcheon’ and ‘royal standard’.
tidal heating	frictional heating of a satellite's interior due to flexure caused by the gravitational pull of its parent planet and possibly neighboring satellites (e.g
gutenberg discontinuity	The Gutenberg discontinuity separates the outer core and the mantle of the Earth.
latin cross throughout	See ‘appendix VIII’, and ‘off-centred cross 2)’ with its following note.
retrograde	The movement of a body in a clockwise direction around the Sun or clockwise rotation on its axis as seen from above the Suns north pole
galactic halo	The circular region surrounding the disk of a spiral galaxy
small-angle equation	The equation giving the relation between the distance D of an object, its diameter d, and its angular size a - alpha (expressed in seconds of arc): a/206,265 = d/D
ecliptic	CELSIUS TEMPERATURE SCALE
semi-sextile	One of the more influential minor easy aspects, the twelfth harmonic, 30°.
periapsis	Point in orbit closest to body it is orbiting.
tornado	TYPHOON
glacier	A glacier is a mass of ice that originates on land, and usually has an area larger than 0.1 km2
snr	(a) Supernova Remnant [LLM96]
apastron	The point in the orbit of one component of a binary system where it is farthest from the other
twisted-pair	A form of wiring consisting of two strands of single wire twisted together to form a transmission line
beam efficiency	Fraction of the total received energy contained in the main beam of an antenna
canton of st. george	The term used when a flag’s canton is formed by the red cross of St George on its white field – a St George’s canton (see also ‘canton 2)’, ‘canton flag’, ‘St George’s Cross 2)’ and ‘St
quarter-field canton	A term that may be used when the canton of a flag is of a different design or colour from its field, and which occupies exactly one-quarter of that field (see also ‘canton 2)').
barometric law	The density distribution of gas in a plane-parallel, isothermal layer acted on by a uniform gravitational field: (z) = (0) exp ( - mg / kT)
amplitude	In physics, the maximum departure of a wave or other periodic phenomenon from the average or zero position
carbon black	A form of amorphous carbon (soot) produced by incomplete combustion of gas (or other organic matter)
s stars	Red-giant stars of spectral type S are similar to M stars except that the dominant oxides are those of the metals of the fifth period (Zr, Y, etc.) instead of the third (Ti, Sc, V)
mass	A measure of the amount of material of an object.
coupling constant	(a) A measure of the intrinsic strength of a force
meridian	(a) Theoretical north-south line on the Earth's surface, or an extension of that line onto the night sky, connecting the observer's zenith with the celestial pole and the horizon
selection rule	A rule whereby changes in quantum numbers can take only certain allowed values: e.g., l = ± 1 or 0 for dipole transitions
flash gate	An ultra-thin transparent electrode across the entire back surface of certain CCDs used to control the charge on the back surface and hence the QE for blue and UV light
million	A thousand thousand (106)
sin	Superconductor Insulator Normal [LLM96]
hydromagnetics	See magnetohydrodynamics
chance	Characteristic of a regime in which predictions cannot be made exactly, but only in terms of probabilities
billion	I use the American version of "billion" which means 1,000,000,000 (1e9); not the British version which means 1e12.
mirror symmetry	In the context of string theory, a symmetry showing that two different Calabi-Yau shapes, known as a mirror pair, give rise to identical physics when chosen for the curled-up dimensions of string theory
infrared	Radiation of wavelength too long to see, usually about 1 to 100 µm.
radar	Radio Detection and Ranging
salinity	SAND
scale-invariant	Most inflationary models predict that the spectrum of density perturbations is nearly scale-invariant, meaning essentially that each wavelength has the same strength
detriment	Said of a planet that occupies the sign opposite its sign of natural rulership (dignity)
shield volcano	a volcano in the shape of a flattened dome, broad and low, built by flows of very fluid lava.
collimator	An arrangement for producing a parallel beam of radiation for use in a spectrometer or other instrument
hyperbolic space	A three-dimensional space whose geometry resembles that of a saddle-shaped surface and is said to have negative curvature
altitude	In the Altitude-Azimuth coordinate system, the angle vertically from the horizon in the celestial sphere.
antiparticle	an atomic particle that has exactly the opposite properties of its counter-part (e.g
king’s colour	See ‘colour 2)’ and ‘colours 2)’.
cauchy dispersion formula	An approximate empirical formula for the index of refraction n as a function of wavelength: n = A + B / 2 + C / 4 +
expansion of universe	Constant increase, with time, in the distance separating distant galaxies from one another
fwhm	Full Width at Half Maximum The full width of a profile (e.g
frequency	Number of electromagnetic oscillations per second corresponding to electromagnetic radiation of any given wavelength.
satellite	A body that revolves around a larger body
ellipse	An ellipse is an oval shape
b-coefficient	See Einstein coefficient
momentum	A measure of the motion of a body equal to the product of its mass and velocity.
waterwheel	The term for a representation of a wheel that usually (but not invariably) provides the motive power for the grinding of wheat or other cereal – a water-wheel or millwheel – see ‘millstone' (also ‘cog-wheel' and ‘windmill'.
rhyolite	fine-grained extrusive igneous rock, commonly with phenocrysts of quartz and feldspar in a glassy groundmass.
synchrotron	A modern form of particle accelerator
weak gauge boson	Smallest bundle of the weak force field; messenger particle of the weak force; called W or Z boson
cpu	Central Processing Unit The part of a digital computer responsible for interpreting and executing instructions
ipf	Instrument Processing Facility
ab variables	A sub-class of Bailey type RR Lyrae variables, having asymmetric lioght curves of large amplitude
indented	See ‘dancetty’ (also ‘embattled').
altazimuth mounting	a telescope mounting that swings from side to side parallel to the horizon, and up and down
bi-septile	A minor hard aspect, separating distance roughly 103° (102° 51' 26"), based on the seventh harmonic (multiples of a septile, 51 1/7°, which is 1/7 of 360°.
heao	High-Energy Astronomical Observatory
interarm region	The area between a spiral galaxy's spiral arms
bell's inequality	one of a family of inequalities concerning the probabilities of joint occurrence of certain events in the two well separated parts of a composite system, implied by any hidden variables theory which satisfies an appropriate locality condition
mathematics	The study of numbers and their properties, and the symbols and operations that can apply to numbers.
celestial mechanics	Study of the movements and physical interactions of objects in space; astrophysical mathematics
isotones	(a) Nuclei with the same number of neutrons but with different A and Z numbers
vega	The brightest star in the constellation Lyra and the fifth brightest star in the night sky
subsidence	CONVECTIVE CONDENSATION LEVEL (CCL)
convection zone	a layer in a star in which convection currents are the main mechanism by which energy is transported outward
isas	Institute of Space and Astronautical Science.
inner lagrangian point	The Lagrangian point (q.v.) through which mass transfer occurs
isotropy	(a) Quality of being the same in all directions
absorption trough	Range of wavelengths (around 21 cm) at which atomic hydrogen absorbs (or emits) radiation; this is a concept used in the attempt to detect intergalactic matter
galactic longitude	A measure of a star's position with respect to the Sun and Galactic center
crystalline	indicates a rock is composed of mineral crystals rather than glass
sidereal day	Twenty-four sidereal hours equal to 23 hours, 56 minutes and 4 seconds of clock time.
translucent	Able to pass radiation, but with much deviation and/or absorption
interline transfer	A CCD construction consisting of vertical strips which are alternately opaque and light sensitive
s-wave	Secondary Wave: A seismic shear wave that moves transversely through Earth
mos	Marine Observation Satellite
lommel-seeliger surface	A surface with large-scale roughness where shadowing effects are important
interferometer	(a) A device for observing the interference of waves of light or similar emanations caused by a shift in the phase or wavelength of some of the waves
subduction	Subduction occurs in regions where two tectonic plates meet, resulting in one plate sliding underneath the other and moving down into the mantle
ergodic motion	Motion by one or more particles which fills phase space with uniform density after a sufficiently long time
constellation	Any of the 88 contiguous regions that cover the entire celestial sphere, including all the objects in each region; also, a configuration of stars often named after an object, a person, or an animal.
optical soliton	a soliton is a wave pulse which propagates without changing shape or dispersion
saha equation	An equation that determines the number of atoms of a given species in various stages of ionization that exist in a gas in thermal equilibrium at some specified temperature and total density
late-gothic shield	The term sometimes used (albeit inaccurately) in vexillology to describe a round-bottomed or Spanish-style shield - but see note below (also ‘rectangular shield’, ‘shield 2)’ and ‘spanish-style shield’).
arc minute	A measure of angular separation, - one sixtieth of a degree.
born approximation	An approach to collision problems by using perturbation methods
tide reducer	The correction that must be applied to a recorded sounding for the height of tide above or below the datum of reference at the time of sounding.
cusp	A line dividing the twelve houses
zenith	The point in the celestial sphere directly overhead; opposite the nadir
limit cycle	The attractor describing a time-periodic regime of a dissipative dynamical system
affrontant	See ‘respectant' in ‘appendix V'.
butterfly diagram	Plot of heliographic latitude of sunspots versus time, developed by Maunder in 1904 to illustrate the solar cycle
perihelion	The closest point in an orbit around the Sun.
energy	Ability to do work.
lorentz invariance	(a) The principle that physics in an inertial frame is independent of the velocity of the frame relative to any other frame
rectification	Refers to the art of correcting a horoscope when the time of birth is unknown in order to find the Ascendant.
chloroplasts	The main energy transformation organelles in plant cells; places where the molecules of chlorophyll are found and photosynthesis occurs.
radio lobes	Extended regions of diffuse radio emission, often dumbbell shaped, that surround a radio galaxy
oblique ascension	A measurement determined by the angle (ascensional difference) between the point on the celestial equator rising with a planet rising at a point not at the equator.
exclusion principle	the idea that two identical spin-1/2 particles cannot have (within the limits set by the uncertainty principle) both the same position and the same velocity
cataclastic	Texture found in metamorphic rocks in which brittle minerals have been broken, crushed, and flattened during shearing.
zenith	Nautical Twilight: When the centre of the Sun is between 6° and 12° below the horizon; the marine horizon becomes invisible.
geometric albedo	Ratio of the flux received from a planet to that expected from a perfectly reflecting Lambert disk of the same size at the same distance at zero phase angle (cf
field	something that exists throughout space and time, as opposed to a particle that exists at only one point at a time
measurement	A quantitative way to present scientific evidence, in the form of a number, an error or uncertainty, and a unit that represents the type of measurement.
relative houses	House three, seven, and eleven, ruled naturally by air signs
color field	Any particle carrying color charge (or strong charge) has an associated color field (or strong field) around it
auto-ionization	(a) The spontaneous ionization of excited atoms, ions, or molecules, as in the Auger effect
ck chondrites	Class of carbonaceous chondrite named for the Karoonda meteorite that fell in Australia in 1930, were initially regarded as members of the CV group
sis	Superconductor Insulator Superconductor [LLM96]
aphelion	The orbital point farthest from the Sun when the Sun is the center of attraction, as opposed to perihelion.
cosmology	The investigation of the origin, structure, and development of the universe, including how energy, forces, and matter interact on a cosmic scale.
plm	Payload Module, the part of the Polar Platform which is mission-specific.
quasi-stationary front	STATION ELEVATION
enso	El Niño Southern Oscillation
uhf	Ultra-high frequency (around 300MHz).
mean sea level	ALTOCUMULUS
right ascension	Is the celestial equivalent of longitude, as measured eastward from the vernal or autumnal equinox and spring equinox.
swan nebula	see Omega Nebula
chlorophyll	Chlorophyll is the pigment in plants that absorbs light rays
einstein	based on the postulates that all the laws of physics are equally valid in all frames of reference, moving at a uniform velocity and that the speed of light from a uniformly moving source is always the same, regardless of how fast or slow the source or its observer is moving
mean anomaly	In undisturbed elliptic motion, the product of the mean motion of an orbiting body and the interval of time since the body passed pericenter
anti-particle	(a) An elementary particle of opposite charge but otherwise identical to its partner
conjunction	an event that occurs when two or more celestial objects appear close close together in the sky.
yy ori stars	A subgroup of T Tau stars with inverse P Cyg type profiles in the CaII and H line emissions
electron-hole pairs	When a photon is absorbed in silicon its energy causes an electron in the valence band to be ejected into the conduction band leaving a (positively charged) vacancy or hole in the valence band
axis	The straight line through a body about which the body rotates.
perihelion	That orbital point nearest the Sun, when the Sun is the center of attraction, as opposed to aphelion.
hawking's theorem	(1) A stationary black hole must be either static (i.e., nonrotating) or axisymmetric
gravity darkening	See von Zeipel's theorem
inharmonious aspects	Aspects in which planetary energies do not combine smoothly, mainly the semi-square, square, sesquiquadrate, quincunx, and opposition; also called difficult aspects
phase	Any one of several predefined periods in a mission or other activity.
scientific method	The method of learning about nature from making observations, formulating hypotheses, and constructing observational or experimental tests to see if the hypotheses are accurate.
quantum determinism	Property of quantum mechanics that knowledge of the quantum state of a system at one moment completely determines its quantum state at future and past moments
gibbous	a phase of the Moon or other planetary object when it is more than half illuminated as seen by the observer
moisture	POLAR FRONT
observer	A person who looks at an object.
homogeneous expansion	To a good approximation, our universe appears to be undergoing homogeneous expansion, which means that successive snapshots of a given region would each look like a photographic blowup of the first snapshot
collimate	To make parallel, neither diverging nor converging
j meson	name for the J- or -meson, mass 3 GeV, composed of a charmed quark and charmed antiquark
siderolite	A stony iron meteorite
landesfarben	See 'national colours 2)' and 'state colours 3)' (also 'livery colours').
time zone	One of 40 divisions of Earth’s surface separated by geographical and political longitudinal lines.
goes	Geostationary Operational Environmental Satellite (USA)
meridian	The great circle passing through the celestial poles and the observer's zenith.
limb	The outermost edge of a planetary body or celestial object
bragg's law	If a beam of x-rays of wavelength is directed at a crystal with parallel crystal planes that are distance d apart, then the reflected x-rays from each plane undergo interference
parallel	A line connecting all points at the same latitude on the surface of the Earth or of any other body.
systolic	the squeezing of the heart ventricles as they push blood along the arteries.
ascending node	The point at which an orbit crosses the ecliptic plane going north.
crystal cleavage	Cleavage is the way a crystal breaks when it is fractured
escape velocity	The minimum speed needed to allow a projectile to move away from a planet and never return to its point of launch
gödel's theorem	A theorem discovered and proved by the mathematician Kurt Gödel in 1931
tertiary	The third mirror to be encountered by the light in a telescope system
brightness temperature	(a) The temperature that a blackbody would have to have to emit radiation of the observed intensity at a given wavelength
inertial frame of reference	Any "standard of rest" or coordinate frame for which Newton's first law is valid
blocking high	CUT-OFF LOW
force	A pull or a push that causes an object to speed up or slow down in a particular direction.
average orbital	speed around the Sun: This is a measure of how fast a planet moves through space, in kilometers per hour.
cosmological principle	Principle incorporating the axioms that there is no center to the universe, that the universe is the same in all directions (isotropic) and the same everywhere (homogeneous), when considered on the largest scales
see-saw	The shaping arrangement in which, according to Marc Edmund Jones, the planets form tow distinct groups roughly opposite each other in a horoscope; symbolizing balance or the need to seek balance as a strong motivating factor.
lambda doublet	Two lines in the microwave region of the spectrum of the OH molecule caused by splitting of electronic levels
hermitian matrix	A matrix which remains unchanged if each element is replaced by its complex conjugate and the rows and columns are interchanged
spacetime	The name often given to the combined ‘fabric' of the Universe where both three dimensional space and time are linked in their four dimensions.
inclination	the inclination of a planet's orbit is the angle between the plane of its orbit and the ecliptic; the inclination of a moon's orbit is the angle between the plane of its orbit and the plane of its primary's equator.
directions	Term given to the method used to predict events based on a Natal or Mundane chart
charge	Quantity carried by a particle that determines its participation in an interactions process
cosmological distances	Distances implied by assuming the validity of the Hubble relation between redshift and distance
column density	The number of particles per square centimeter along a specified path with a length equal to the distance to the probing source
standard deviation	The root mean square deviation from the arithmetic mean
statistical equilibrium	A state in which the average density of atoms per cubic centimeter in any atomic state does not change with time and in which, statistically, energy is equally divided among all degrees of freedom if classical concepts prevail
galley ensign	In largely Mediterranean usage, a distinctive ensign or flag now obsolete, that was specifically flown from a warship whose principal motive power came from her oars rather than her sails (see also ‘ensign’ and ‘galley’).
eccentricity	The eccentricity of an ellipse (orbit) is the ratio of the distance between its focii and the major axis
saros	(a) A particular cycle of similar eclipses (lunar or solar) known to the Babylonians, that recur at intervals of 6585 days (about 18 tropical years)
harmonic law	See Kepler's third law
corona	Very hot, tenuous, outer layer of the solar atmosphere, fully ionized, affected by the solar magnetic field, region from which solar wind is emitted
magnetic field	The region surrounding an object which has a changing electric field
filet cross	A term sometimes used to describe a plain cross with narrow arms – but see ‘filet' and ‘cross 1)' (also ‘fillet 1)' and ‘fillet 2)').
crater	a bowl-shaped depression formed by the impact of an asteroid or meteoroid
dark adaptation	the process by which the human eye increases sensitivity under conditions of low, or none, illumination
albedo feature	a dark or light marking on the surface of an object that may or may not be a geological or topographical feature
schmidt camera	Telescopic camera incorporating an internal corrective lens or plate that compensates for optical defects and chromatic faults in the main mirror
constant pressure surface	PRESSURE CHANGE
cmd	Color-Magnitude diagram [BFM02]
germanium	Symbol:"Ge" Atomic Number:"32" Atomic Mass: 72.59amu
rupes	the term applied to scarps on planetary surfaces; many scarps are thought to be the surface expression of faults within the crust of the planetary object.
metar	HEAT
visual meteor detection	The monitoring of meteor activity by an observer or group of observers using the unaided eye
radix	From the Latin, literally root
grating	See diffraction grating
co-moving coordinates	(a) A set of coordinates which do not change in an expanding (or otherwise moving) medium
barometric pressure	ISODROSOTHERM
half-power beamwidth	(HPBW) The angle across the main lobe of an antenna pattern between the two directions where the sensitivity of the antenna is half the value at the center of the lobe
tholus	small dome-shaped mountain or hill
birthtime	The moment of first breath of a new born.
constellation	Random patterns of stars in the night sky produced by the chance alignment of stars of different luminosities and distances
protoplanet	a stage in the formation of a planet which implies the body is nearly full-size
electron shells	Zones in which the electrons in atoms reside
librations	Variations in the orientation of the Moon's surface with respect to an observer on the Earth
specific humidity	Specific humidity (q) is the ratio of the mass of water vapour to the mass of dry air plus water vapour in a particular volume of air
host computer	The main or master computer in an instrumentation system
true vacuum	This phrase has the same meaning as vacuum, with the word "true" being used only to emphasize the distinction with the false vacuum
kin	name for the
mass	A measure of the total amount of material in a body, defined either by the inertial properties of the body or by its gravitational influence on other bodies.
axis	A straight line used as a reference or about which an object can turn.
divergence	COOLING DEGREE DAY
asinh magnitude	Magnitudes expressed as the inverse hyperbolic sine (or ``asinh''), sometimes referred to informally as luptitudes
double asteroid	Two asteroids that revolve around each other and are held together by the gravity between them
cosmology	a branch of science that deals with studying the origin, structure, and nature of the universe.
telescope	A device that uses lenses or mirrors to collect, focus and magnify light from distant objects
patera	shallow crater; scalloped, complex edge.
minkowski space	(a) A four-dimensional spacetime with a flat (i.e., Euclidean) geometry, which is used in the special theory of relativity
heliopause	The boundary theorized to be roughly circular or teardrop-shaped, marking the edge of the sun's influence, perhaps 100 AU from the sun.
umbra	The shadow cast by an eclipsing body during a total eclipse; also the central, dark region of a sunspot group.
fetch	SYNOPTIC CHART
existence theorems	these are the theorems that assert the existence of mathematical objects satisfying a specific set of axioms
chromosphere	A reddish-colored layer in the solar atmosphere, just above the photosphere.
compactification	(a) The process in which a space of many dimensions effectively reduces its dimensions
rising sign	Synonymous with Ascendant
absolute zero	the temperature at which the motion of all atoms and molecules stops and no heat is given off
of symmetry	Point through which an inversion operation is performed, converting an object into its mirror image
light cone	a surface in space-time that marks out the possible directions for light rays passing through a given event
black hole	a collapsed object with such strong gravity that nothing can escape it; as a result, the object is black, and it is a hole because nothing can escape from it
penumbra	The region of a partial shadow that takes place during an eclipse.
superconductivity	(a) A phenomenon occurring in some metals at very low temperatures, in which the resistance drops to zero and the metal shows many other anomalous properties
retrograde	the rotation or orbital motion of an object in a clockwise direction when viewed from the north pole of the ecliptic; moving in the opposite sense from the great majority of solar system bodies.
gamma ray burst	A strong burst of gamma rays from an unknown source
ionosphere	A region of the Earth’s upper atmosphere where solar radiation ionizes the air molecules
sky	CIRROSTRATUS
tuff	the general term for consolidated pyroclastic debris.
alfvén speed	The speed at which hydromagnetic waves are propagated along a magnetic field: (VA) = B / (4 )1/2
antares	( Sco) (a) A red supergiant star in the constellation Scorpius
officer’s pennants	The term that may be used to describe those pennants (often - but not exclusively - a swallow-tailed version of the relevant club burgee or flag) flown by the past or present officers of a club, especially of a yacht or boating club – a flag officer, yacht officer or officer's broad pennant or a yacht officer's pennant – but see ‘officer's flags’ and ‘broad pennant 3)’ (also ‘burgee’ and ‘swallow-tail(ed)’).
singularity	The center of a black hole, where the curvature of space time is maximal
crêpe ring	(a) Rather transparent inner ring (Ring C) of the saturn ring system
one-standard-deviation uncertainty	An estimate of the uncertainty of a measurement which is specified so that the probability of the true value of the measured quantity lying within the uncertainty interval is two out of three
solar apex	A point on the celestial sphere lying in the constellation Hercules toward which the Sun and the solar system are moving with respect to the Local Standard of Rest at a rate of about 19.4 km per second (about 4.09 AU per year)
star cluster	A gathering of stars in a relatively small region, which are gravitationally bound to each other.
weak gauge symmetry	Gauge symmetry underlying the weak force
terra	an extensive land mass.
milne-eddington approximation	A first approximation in the analysis of stellar spectra, in which a line is assumed to be formed in such a way that the ratio of the line absorption coefficient to the continuous absorption coefficient is constant with depth
ellipse	oval
radon	Alpha particles can be stopped by a piece of paper and are only a concern when alpha-emitting isotopes are taken into the body (e.g., by inhalation)
gaussian distribution	A statistical distribution defined by the equation p = c exp(-k2x2), in which x is the statistical variable
king’s jack	See ‘His Majesty's Jack'.
counting rate	see Proportional Counter
gain	The amplification factor
wien's law	A law stating that the wavelength of the peak amount of thermal radiation from any material is inversely proportional to the temperature.
ellipse	A closed, oval-shaped curve (generated by passing a plane through a cone) describing the shape of the orbit of one body around another.
s.i.g.h.t.	Stands for Service, Information, Guidance and Hospitality for Travelers
array	In radio astronomy, an arrangement of antenna elements designed to produce a particular antenna pattern
cubic crystal	A crystal shaped like a cube
critical temperature	The temperature that must be reached in order for a new nuclear reaction to begin within a star
hess diagram	(a) A diagram showing the frequencies with which stars occur at various positions in an H-R diagram
thales	639-546 B.C., studied in Egypt and left nother in writing, but is said to have predicted an eclips which caused much alarm and ended the battle between the Medes and Lydians.
activity	Symbol: A For a radioactive substance, the average number of atoms disintegrating per unit time
epoch	A date chosen as a reference point for observation
solar wind	Flow of lightweight ions and electrons (which together comprise plasma) thrown from the sun.
cavus	A hollow, irregular depression.
observation	PRESSURE CHARACTERISTIC
aircraft insignia	1) Specifically in US military usage, the term that refers to markings of identification on the tail plane/fin of primarily (but not exclusively) military aircraft (see also ‘roundel 1)')
2 test	A least-squares statistical test that measures the probability of randomness in a distribution
hayashi track	Hayashi track is a phase in the life cycle of a star in which its luminosity decreases but he surface temperature remains the same and the star enters the main sequence in the H-R diagram.
reversing layer	Lower chromosphere of the Sun, a comparatively cool region in which radiation at certain wavelengths is absorbed from the continuous spectrum emitted from the Sun's photosphere
cryosphere	Portion of Earth which consists of the ice masses and snow deposits (continental ice sheets, mountain glaciers, sea ice, surface snow cover and lake/river ice)
spring	ICELANDIC LOW
absorption band	see Band Spectrum
stellar population	A Galaxy-wide group of stars of all types that have similar ages, locations, kinematics, and metallicities
mie scattering	Scattering of light (without regard to wavelength) by larger particles, such as those of dust or fog in Earth's atmosphere (see also Rayleigh Scattering)
iemers	Members of Inland Empire Mensa
forward bias	A term applied to an electronic device known as a diode - usually formed by a junction of p-type and n-type semiconductor material - in which current flows easily if the externally applied voltage has the correct polarity or direction
rr lyrae stars	A large class of pulsating (amplitude variation about 1 mag) blue giants of anomalous spectral type (A2-F6) with periods of less than 1 day
area	Measures the size of a surface using length measurements in two dimensions.
earth	intercepts a stream of
planitia	plateau or high plain
cosmic ray astronomy	the astronomy associated with the detection, propagation and origin of cosmic rays from their sources to the Earth
earth	23 hours, 56 minutes, 4.091 seconds to complete one full turn relative to the stars, versus exactly 24 hours relative to the Sun
sidereal time	Refers to a way of indicating distance around the circle of the Houses or Celestial Equator, counterclockwise from the Vernal Equinox, by hours and minutes instead of degrees.
circle	An ellipse possessing but one focus
quincunx	An arc of 150 degrees
coma x-1	An extended X-ray source in the Coma cluster of galaxies
inertial frame	a frame of reference in which force-free bodies move along straight lines; postulates of special relativity are said to be valid in an inertial frame
shear	A stress applied to a body in the plane of one of its faces
henyey track	An almost horizontal track of stellar evolution between the Hayashi track and the main sequence
information	a measure of the delocalization of the state of the system in the space of all possible events
aberration	(a) Defect in the image formed by a lens, mirror or optical system
side lobe	In radio astronomy, a component of the reception pattern of an antenna away from the main beam, representing a direction in which the antenna is sensitive when it should be insensitive
lut	Look-Up Table [McL97]
comet	Cooperative programme for Operational Meteorology Education & Training
force	A push or pull two or more objects.
energy flux	the rate of flow of energy through a reference surface
altitude	TROUGH
monosaccharide	A monosaccharide is one sugar molecule
carbonate	Mineral or compound containing carbon and oxygen (i.e
rotation curve	Orbital velocity as a function of distance from the center of a galaxy
c stars	Late type giants with strong bands of carbonated molecules (C2, CN, CH) and no metallic oxide bands
z camelopardalis stars	A class of dwarf novae (q.v.) with standstills in their light curves
air	MONSOON
absorption spectrum	Dark lines superimposed on a continous spectrum.
cosmological constant	Term that can be added to the equations of general relativity to give a static solution.
tail	See ‘tongue(s)’.
active sun	The Sun during its 11-year cycle of activity when spots, flares, prominences, and variations in radiofrequency radiation are at a maximum
specific intensity	see Intensity [H76]
septile	The seventh harmonic, 51 3/7°
morphology-density relation	The observation that the relative number of spiral and elliptical galaxies depends on the density of the region
sidereal hour angle	Angular distance on the celestial sphere measured westward along the celestial equator from the catalog equinox to the hour circle passing through the celestial object
supersonic	Describing a speed that is greater than the speed of sound in the medium concerned
full cut-off street light	Street lights that don't allow light to escape from their lamp assembly above the horizontal
fixed	See ‘throughout'.
native	A traditional term that refers to a person for whom a horoscope is erected.
hard aspects	Aspects that stimulate action or tension and induce motivation
galactic pole	(a) Either of the two points in the sky where we look perpendicular to the disk of the Milky Way
primary directions	Originally, a mathematically complicated system of progressing a horoscope based upon the diurnal rotation of the Earth
solar flare	explosion on the sun?s surface causing a flaming arch millions of miles long, due to a shift in the sun?s magnetic field.
badge pennon	The term for a medieval lance pennon (usually carried by those mounted men-at-arms who were non-armigerous) that displayed a heraldic badge against livery colours – but see ‘pennoncel' (also ‘armigerous', ‘banneret 2)', ‘Badge in Heraldry', ‘lance', ‘livery colours 1)', ‘pennon 3)') and ‘pennoncier'.
colloquium	Similar to the AG, this AMC-organized annual event emphasizes serious thought and discussion in a singular subject or theme
dovetail plate	A type of mounting plate, which attaches a telescope tube to a mount
concave	Curving inward, away from the viewpoint
directions	A term synonymous with progression
right ascension	the longitude of a point on the celestial sphere using the equatorial coordinate system; right ascension divides the sky into 24 sections called hours (1 hour = 15 degrees)
superspace	Supersymmetry can be formulated in several ways
ensemble average	An average over an ensemble of all possible systems
sextile	Minor Aspect in which the planets are two signs apart or 60 degrees
palm	A term for the square or rectangular part of any flag that carries a schwenkel, or whose fly is divided into tongues (see also ‘crutch’ ‘indentation(s)’, ‘schwenkel’, ‘swallow-tail(ed)’, ‘swallow-tail and tongue’ and ‘tongue(s)’).
macroscopic	Refers to scales typically encountered in the everyday world and larger; roughly the opposite of microscopic
ecliptic	circle in which the earth's orbit's plane (ecliptical plane) intersects the celestial sphere
galactocentric distance	A star's distance from the Galactic center
grism	This is a right-angled glass prism with a transmission diffraction grating deposited on the hypotenuse surface
equipartition of energy	(a) If all stars have the same kinetic energy, equipartition of energy prevails
frequency	A property of a wave that describes how many wave patterns or cycles pass by in a period of time
habitable zone	The distance from a star in which a planet can sustain liquid water on its surface.
saw-toothed	See ‘serrated’ (also ‘wolfteeth’).
solar flare	A sudden, short lived, burst of energy on the Sun's surface, lasting from minutes to hours.
nomcomm	Nominating Committee
elastic collision	A collision between two particles which conserves the total kinetic energy and momentum of the system
orbit	The path of one object about another (used here for an object orbiting the sun).
companion star	Either one of a binary star system (although usually the less massive), sometimes only detectable by spectroscopy
circumpolar	A celestial object that never sets but always stays above the horizon
maclaurin series	a power series expansion of f(x) of the form f(x) = f(0) + f'(0) x + [f"(0)/2!] x2 +
hugoniot relations	Relations expressing conservation of baryon number, momentum, and energy across a shock front
rest-mass energy	The energy which a particle has even when it is at rest
fet	Field Effect Transistor A tiny transistor amplifier in which the current flow between two terminals, called the source and the drain, is controlled by the electric field generated inside the silicon by an external voltage on a surface called the gate electrode
effusive eruption	a relative quiet volcanic eruption which puts out basaltic lava that moves at about the speed one walks; the lava is fluid in nature; the eruptions at the Kilauea volcano on the island of Hawaii are effusive
minor shower	A meteor shower with a Zenith Hourly Rate (ZHR) of fewer than 10 per hour.
albedo	This term is a unit-less measure that refers to the how much an object diffusely reflects light from the sun
tidal heating	the frictional heating of a satellite's interior due to flexure caused by the gravitational pull of its parent planet and possibly neighboring satellites.
secular change	A continuous, nonperiodic change in one of the attributes of the states of a system
cam plants	Plants that utilize the CAM process, in which CO2 is stored in the form of an acid before use in photosynthesis
mean solar second	1/86,400 of a Mean Solar May (cf
state property	A state property is a quantity that is independent of how the substance was prepared
gray atmosphere	A model atmosphere in which the continuous absorption coefficient is assumed to be independent of frequency
scarp	A line of cliffs produced erosion or by the action of faults.
altitude	Angle above the horizon, in degrees
nucleic acid	The large molecule on which genetic material is based.
irregular galaxy	A type of galaxy that does not have a regular shape
solstice	One of the two points on the ecliptic at which the Sun appears to be farthest away from the celestial equator (representing therefore mid-summer or mid-winter)
mercurial barometer	BAROMETRIC PRESSURE
dmc	Disaster Monitoring Constellation - DMC website The Disaster Monitoring Constellation is a series of two satellite constellations, as part of an international effort to monitor and provide observational support in the event of natural disasters
zenith	The point in the sky directly over the observer's head, and 90° from the horizon in every direction.
natal	Birth
out-gassing	(a) The absorbed gases released from the interior walls and components of a vacuum chamber which has already been "roughed-out"
nmsf	Net Multiplicative Scaling Factor
local time	Represents the time of the reader, and the local time given on this website should be no more than about 30 minutes off for most of the people in the world.
sobieski	Former name of the southern constellation Scutum
magnetic field lines	imaginary lines that indicate the strength and direction of a magnetic field
inertia	Property of a moving body to continue moving at the same speed in the same direction - or of a static body to remain static - unless and until acted upon by some force for change
flare	a sudden eruption of energy on the solar disk lasting minutes to hours, from which radiation and particles are emitted.
covalent bond	A chemical bond where electrons are shared between two atoms
zino	The supersymmetric partner of the Z boson.
depth	See ‘width 1)’.
precipitation	GROUND FOG
retrograde	Motion which is backwards as compared to the standard direction
comet	A small, icy, rocky chunk of material in orbit around the Sun
microwave	(a) An electromagnetic wave (in the radio region just beyond the infrared) with a wavelength of from about 1 mm to 30 cm (about 109-1011 Hz)
hour circle	A great circle passing through the celestial poles - i.e., perpendicular to the celestial equator
monte carlo method	A trial-and-error technique used on computers to solve complex problems
space-time continuum	(a) A four-dimensional framework in which events take place
galactic equator	The primary circle defined by the central plane of the Galaxy
co-moving sphere	A hypothetical and arbitrary spherical surface (about any point) that is expanding along with the rest of the Universe
proportion	An equality between two ratios.
rms	Root Mean Square
kelvin	A temperature scale used in sciences such as astronomy to measure extremely cold temperatures
mass fraction	The fractional amount (by mass) of a given element or nuclide in a given composition
x-ray astronomy	the field of astronomy that studies celestial objects by the x-rays they emit.
avogadro constant	(a) Symbol: NA number of particles in one mole of a substance
materialism	Belief that material objects and their interactions constitute the complete reality of all phenomena, including such seemingly insubstantial phenomena as thoughts and dreams
entropy	The measure of disorder in a physical system, which always tends to increase with time
orbit	The path that an object moves around a second object or point
critical phenomena	the phenomena which occur in the neighborhood of a continuous phase transition, characterized by very long correlation lengths
solar chart	A horoscope that is set up with the placement of the Sun positioned at the Ascendant
declination	This is the the number of degrees an object is north or south of the celestial equator
atomic number	Number of protons in an element.
principia	The common name for Newton's ‘Philosophae naturalis principia mathematica', which deals with the mechanics of the Solar System, including his law of gravitation, laws of motion and derivations of Kepler's laws.
scientific notation	A convenient way of recording and manipulating very large and very small numbers
radius	Half the diameter of any sphere or circle
relativity	(a) The theory of how motion and gravity affect the properties of time and space
scarp	line of cliffs produced by faulting or erosion
new	a phase of the Moon or other planetary object when it is unlit as seen by the observer; occurs when the object is at inferior conjunction
spectral lines	A rainbow shows the small slice of the entire electromagnetic spectrum that humans can see
absorption lines	Narrow spectral features that represent a reduction in intensity over a small wavelength range
albedo	(a) The ratio of the amount of light reflected from a surface to the amount of incident light
attenuation	(a) The reduction of intensity of a radiation as it passes through a medium
ephemeris transit	The passage of a celestial body or point across the ephemeris meridian
crystal lattice	Atoms or groups of atoms repeated at regular intervals in three dimensions with the same orientation
ibd	International Board of Directors.
mineral vein	A strip of pure mineral found in a rock
zodiac	Odin was the king of the gods...
moving cluster	A physical grouping of stars moving through space that usually shares a common origin
ising model	a simplified version of the Heisenberg model in which the atomic spins must be aligned parallel or antiparallel to a given direction
g-band	A band of CH at 4303 Å
remote sensing	the process of collecting information with instruments that record various forms of energy
renormalisation group	the way in which coupling constants enter into field theory often involves certain simple scaling relations that are described by a group (in the mathematical sense), In statistical mechanics, the renormalization group method systematically implements some form of coarse-graining operation to expose the character of the large-scale phenomena, in physical systems where many scales are important
sunspot	An area on the Sun's surface that is cooler than its surroundings and has intense magnetic activity.
valence	Also valence band or valence electrons; the electrons in the outermost orbit
centre of mass	The point in a body, or system of bodies, at which the whole mass of the system can be assumed to be concentrated.
elliptical galaxy	a galaxy whose structure shaped like an ellipse and is smooth and lacks complex structures such as spiral arms.
modified julian date	abbr
entanglement	the impossibility of expressing certain quantum mechanical states of a system with two or more parts as the conjunction of definite quantum states of the separate parts
encounter	see Gravitational Encounter
archiving	Making a permanent record which can be accessed later at any time
planum	a high plain or plateau.
sco-cen association	An association of very young stars about 200 pc distant in the Gould Belt
scholastics	Adherents to the philosophy and cosmology of Aristotle
lipper	Slight ruffling or roughness on a water surface
radius	In astronomy, an old instrument for measuring the angular distance between two celestial objects
hubble tuning fork	The diagram created by Edwin Hubble to classify galaxy types into spiral, barred spiral, elliptical and irregular.
string coupling constant	A (positive) number that governs how likely it is for a given string to split apart into two strings or for two strings to join together into one-the basic processes in string theory
h-line	An Mg II resonance line at 2803 Å
fatty acid	A fatty acid has a carboxylic acid on a long chain of carbon atoms
critical path	A term used in project planning to indicated a segment of the proposed work which if not completed on time will result in one or more other segments being delayed with serious "knock-on" effects for the project
luminescence	(a) The emission of radiation from a substance in which the particles have absorbed energy and gone into excited states
byo	Bring Your Own: Commonly seen as BYOB (bring your own beverage), BYOG (games), etc.
solstice	22 June, and 22 December
cycle	The time it takes a planet or point to make one complete revolution in the heavens.
stoichiometry	The study of the relationships between amounts of products and reactants.
temperature	Absolute temperature measured in Celsius degrees, with the zero point at absolute zero.
ionization	The process by which ions are produced, typically by collisions with other atoms or electrons, or by absorption of electromagnetic radiation.
static limit	a limit close to a black hole inside of which is impossible to remain at rest
argos	Data collection and location system on NOAA/POES
metar	SANTA ANA WINDS
standard ruler	Any extended celestial object which is more or less constant diameter
gsd	Greenwich Sidereal Date The number of sidereal days elapsed at Greenwich since the beginning of the Greenwich sidereal day that was in progress at Julian date 0.0
axis	an imaginary line about which an object rotates
rms	root mean square
decile	A mildly benefic aspect with a separation of 36°, also called a semi-quintile; the tenth harmonic.
composition	The chemical makeup of an object.
least action	see Action [P88]
light year	A measure of distance, the distance light travels in one year, about 63,197 AU.
excited state	A greater-than-minimum energy state of any atom that is achieved when at least one of its electrons resides at a greater-than-normal distance from its parent nucleus.
south galactic pole	A point in the constellation Sculptor toward which our line of sight is perpendicular to and below the Galactic disk
horizon	The horizon is an imaginary circle that delimits the sky and the Earth, or an extension of the plane of the observer (at an altitude of 0 degrees).
wavy flame	In English then British usage, now obsolete, the term used to describe a pile wavy as it appeared on military colours – see ‘pile(s) wavy' (also ‘flammes', ‘pile 2)', ‘stand 1)', ‘venn' and ‘wavy' ).
falling diagonal	See 'descending diagonal'.
kaon	variety of strange meson
selective absorption	The reddening of starlight in passing through fine particles of interstellar dust
feghoot	A tongue-in-cheek story or joke with a pun as the punch
au	O Objective Lens (or Object Glass): The lens in a binocular tube or refractor that is closest to the object under observation.
altitude	The angle of a body above or below the plane of the horizon; negative altitudes are below the horizon.
cap badge	See ‘badge 3)’.
law of universal attraction	Isaac Newton's formulation of the law of gravity
quintile	A minor Aspect wherein planets are approximately 2 and one-half signs apart or 72 degrees.
james union	An unofficial name for the 1606 pattern British union flag (see also ‘British flag’, ‘His Majesty's jack', ‘interlaced' ‘conjoined’ and ‘union jack’).
background radiation	Weak microwave radiation coming from space in all directions
transit	Odin was the king of the gods...
oxygen	Symbol:"O" Atomic Number:"8" Atomic Mass: 16.00amu
dq herculis	A slow nova
radar	a system using pulsed radio waves to detect the position of objects by measuring the time it takes a single pulse to reach the object and be reflected back
line spectra	Also called absorption spectra, these arise when photons of specific frequency are absorbed by cooler gas, leaving a darker line on a background continuum region
oblate	An oblate sphere is one that is flattened at its poles
multi-coated lens	Several clear coatings of a dedicated material that reduce unwanted reflections when applied to a lens or a corrector plate.
table of houses	An astrological reference table, correlated with a particular house system, which lists the zodiacal positions of house cusps at various latitudes according to sidereal time.
stationary nonequilibrium state	time-independent state of a system subjected to fixed constraints
ideogram	See ‘mon 1)’ and its following note.
analyzer	A device for determining the plane of polarization of plane-polarized radiation
metallicity gradient	The progressive change in metallicity from the center of a galaxy to its edge
thermosphere	CHEYENNE FOG
storage ring	A ring in which particles are kept in a circular motion, suspended in a magnetic field, until they can be injected into the larger ring of an accelerator
long count	a system for the designation of dates used by the Mayans but probably by other Central Americal peoples as well
ag	Annual Gathering
potential energy	Stored energy, or energy with the potential to do work
spectral energy distribution	SED: The distribution of a star's light among various wavelengths
fictitious flag	A flag – or the illustration of a flag - that purports to represent an actual entity or person, but for which no evidence of any such use by that entity or person exists – but see ‘flagoid’ (also ‘false flag 1)’, ‘fictional flag’ above, ‘flag of pretence 1)' and ‘replica flag').
descate	(adj) A term used to describe a rounded (or lanceolate) fly into which a ‘V’ shaped notch has been cut, and a shape often seen in UK cavalry guidons – cloven descate or rounded swallowtail (see also ‘fly 1)’, ‘guidon 2)’, ‘hussar cut’, ‘lanceolate’, ‘pennant’ and ‘swallow tail(ed)’).
aurora	a glow over the polar regions caused by the interaction between Earth's magnetic field and charged particles from the Sun
aplanatic system	A system of three lenses which, taken together, correct for spherical aberration, chromatic aberration, and coma
chlorine	Symbol:"Cl" Atomic Number:"17" Atomic Mass: 35.45amu
solar flares	Eruptions in the outer part of the Sun's atmosphere.
zenith	(a) The point in the sky directly overhead
aster	Advanced Spaceborne Thermal Emission and Reflection Radiometer
aperture	The size of the main mirror or lens of a telescope
gos	Global Observing System
lagrange points	Five points with respect to an orbit which a body can stably occupy
spectroscopy	The use of spectra to find information about astronomical objects.
double-star system	a system of two stars in orbit around each other
geometrical horizon	This expression is sometimes applied to the celestial horizon.
metar	FREEZING FOG
quartered diagonally	In vexillology, a phrase that may be used in place of the heraldic term per saltire - see ‘per saltire 1)'.
isobars	Nuclei with the same A number but different Z numbers
angular frequency	(Pulsatance) Symbol: The number of complete rotations per unit time
sputnik 1	First artificial Earth satellite, launched by the Soviet Union on 4 October 1957
spectral ratio	The ratio of electromagnetic wavelengths from different cosmic epochs
metar	SLUSH
local group	Most Mensans are assigned to one of the 134 local groups in American Mensa, based on geography
luminosity	This can be used to determine distances.
jerusalem cross	A cross-potent cantonée - see ‘cross cantonée’ and following note in ‘appendix VIII’, also ‘cross potent’ in ‘appendix VIII’.
astrochemistry	the branch of science that explores the chemical interactions between dust and gas interspersed between the stars.
astrometric binaries	see Binary System
equilibrium	A state in which there is no net change in a system.
planetoid	Another term for a minor planet – the official name for asteroids, as used by the International Astronomical Union (IAU).
last quarter	a phase of the Moon or other planetary object when it is exactly half illuminated as seen by the observer; occurs between the full and new phases
system flow	The evolution of the spectrum of configurations, or the associated effective coupling constants, under the action of repeated coarse-graining
scarp	line of cliffs produced by faulting or erosion.
conservation of angular momentum	(a) The principle that the angular momentum of a system (the momentum of rotation about a point) remains the same as long as no external torque acts
zenith	NATIONAL CENTER FOR ATMOSPHERIC RESEARCH (NCAR)
onomast	See ‘name pennant’.
fossa	long, narrow, shallow depression
harmonic overtone	Any integral multiple of the fundamental frequency (q.v.)
universality class	This is a way of classifying the behavior of systems near the critical points of continuous phase transitions
schrödinger equation	(a) Equation governing the evolution of probability waves in quantum mechanics
characteristic value	see Eigenvalue
look-back time	(a) Phenomenon that, owing to the finite velocity of light, the more distant an object being observed, the older is the information received from it
mute signs	the water signs; Cancer, Scorpio and Pisces, so-called because they are traditionally depicted as mute creatures: the crab, the scorpion and the fish, respectively
humidity	CONSTANT PRESSURE SURFACE
radiant	The point from which meteors appear to eminate in the sky
angstrom	commonly used to measure the wavelength of light; equal to 10-10 meters
o ceti	see Mira
typhoon	TROPICAL DEPRESSION
gyrofrequency	The frequency with which an electron or other charged particle executes spiral gyrations in moving across a magnetic field
littrow	The configuration of a diffraction grating spectrograph in which the diffracted ray returns along the same direction as the incident ray
correlation length	the correlation length gives a measure of the typical distance over which the fluctuations of one microscopic variable are correlated with the fluctuations of another
rastafarian/rasta colours	Symbolic of the Rastafarian movement, and (like the pan-African colours and identical to them) based upon the flag of Ethiopia – see ‘pan-African colours’.
noaa	National Oceanographic and Atmospheric Administration - NOAA website NOAA is an American organisation dedicated to studying the the oceans and atmosphere in the interest of predicting changes to the climate, weather and oceans.
shot noise	Noise, or fluctuations in the current of a detector, due to the fact that the current is carried not by a smooth fluid, but by a large number of individual electrons (cf
coded mask	Coded masks are used for imaging high-enery x-ray and gamma radiation that cannot otherwise be focused by lenses or mirrors
obliquity	In general the angle between the equatorial and orbital planes of a body or, equivalently, between the rotational and orbital poles
charge number	see Atomic Number
boost factor	The quantity = 1 / sqrt(1 - v2 / c2) in the special theory of relativity that relates measurements in two inertial frames
umbra	the area of total darkness in the shadow caused by an eclipse.
geniture	From the Latin, birth or origin; used in astrology to refer to a birth or a natal horoscope
boltzmann constant	Symbol: k (a)The constant 1.380 54 x 10-23 J K-1, equal to the gas constant (R) divided by the Avogadro constant (NA)
coherence	The existence of a correlation (statistical or temporal) between the phases of two or more waves
azimuth	(a) Directional bearing around the horizon, measured in degrees from north (0°)
meteorite	A natural object from space that hits the surface of a planetary body
longwave radiation	The thermal radiation emitted by the Earth in the infrared part of the electromagnetic spectrum
isolated m	A group and newsletter for isolated Mensans who may be unable to participate in local group activities due to health or geographical factors
patera	a shallow crater with a scalloped, complex edge
snow	SNOW CRUST
commensurate orbits	A term applied to two bodies orbiting around a common barycenter when the period of one is an integral multiple of that of the other
closure	A mathematical term which says that if you operated on any two real numbers A and B with +, -, * or /, you get a real number.
aips	Astronomical Image Processing System -- National Radio Astronomy Observatory
summer	SUMMATION LAYER AMOUNT
cobalt	Symbol:"Co" Atomic Number:"27" Atomic Mass: 58.93amu
clustering	Any group of objects where the average spacing is less than the average spacingof a randomly distributed population is said to be clustered
reaction rate	The rate at which a chemical or nuclear reaction proceeds
bose-einstein condensation	A phenomenon in which several thousand atoms of certain elements are able to combine to form a single entity (a superatom) at very low temperatures
boussinesq equations	Hydrodynamic equations often used to analyze the onset of convection in a fluid by allowing for the variations of density only insofar as buoyancy forces are concerned
equinox	the two points at which the Sun crosses the celestial equator in its yearly path in the sky
tornado	DEEPENING
megaton	an explosive force equal to one million metric tons of TNT
major axis	The maximum diameter of an ellipse.
magnetic pole	Region on a body where magnetic inclination is at a maximum.
chemical evolution	The chemical (i.e., pre-biological) changes that transformed simple atoms and molecules into the more complex chemicals needed for the origin of life
ranger spaceprobes	Series of 9 US spaceprobes only the final 3 of which were successful
sis	Solid-state Imaging Spectrometer (ASCA X-ray satellite).
gravitational sigularity	a region where the gravitational field has become so strong that the curvature of space-time is infinite
holmium	A soft malleable silvery element of the lanthanoid series of metals
micro-	A prefix meaning 10-6
compounds	It has an important function in the neurological system in animals (including humans).
eccentrics	In Ptolemaic cosmology, displacement of the center of a rotating celestial sphere from the center of the Universe
chaotic inflationary universe theory	A version of the inflationary universe theory, proposed by Andrei Linde in 1983, for which the energy density diagram for the fields driving inflation can be as simple as a bowl, with a unique minimum at the center
eddies	Eddies are whirlpool like transient features in the ocean and atmosphere
densan	Has various definitions: someone with an I.Q
heaviside layer	See E layer
ms stars	M-type stars with ZrO bands
mesoscale convective complex	MESOSPHERE
time	The property that stops all events happening at the same point from coinciding.
bandwidth	(a) The width of the portion of the electromagnetic spectrum (the range of frequencies) that is permitted to pass through an electronic device (measured in cycles per second)
blackbody curve	Plot of energy level against wavelength for heat or other radiation emitted by an object capable of absorbing all the energy that strikes it
crater	bowl-shaped depression formed by the impact of a meteoroid; depression around the orifice of a volcano
ergosphere	The region surrounding the event horizon (but inside the stationary limit) of a rotating Kerr black hole (see Ergoregion)
parallax	The shift of an object when it is viewed from two different places
sedimentary rocks	A type of rock formed from hardened deposits of sediments.
proton	's electrical charge has the same
order parameter	a variable such as magnetisation used to describe the degree of order in a phase below its transition temperature
arm population	Young stars typical of those found in spiral arms (Population I stars)
achromat	An achromatic lens
metal-enhanced star formation	A hypothesis according to which stars form preferentially from regions of above-average Z in a chemically inhomogeneous interstellar medium
root mean square	The square root of the mean square value of a set of numbers
equatorial co-ordinates	A system of celestial co-ordinates that uses the celestial equator as the reference plane and the First Point of Aries as the reference direction
antoniadi scale	a roman numeral indicates the quality of seeing according to the following scale:
descendant	The opposite point from the Ascendant: cusp of the 7th house
mimas	The second innermost satellite of Saturn, discovered by Herschel in 1789
solar	masses, the maximum mass a dying
superfluid	A liquid which undergoes the phenomenon of superfluidity, below the temperature at which this phenomenon sets in
galaxy	. Astronomers have also used radial velocity measurements to observe that most objects beyond our galaxy travel away from us at speeds that increase with the object's distance.
ionosphere	A region of the Earth's atmosphere.
trine	The third harmonic, 120°; the most influential major easy aspect
stable	CONDUCTION
bih	Bureau International de l'Heure
apparent solar day	Interval between two successive culminations of the Sun - i.e., the period from apparent noon to apparent noon
national ornament	A decorative strip (usually placed along he hoist of a flag) intended to represent a folk or traditional element of national culture, and particularly prevalent among Eastern Slavic and Siberian states such as Belarus, Kazakhstan and Mariy El – see ‘folklore ornament'.
configuration mixing	The superposition of a number of wave functions belonging to different configurations
b galaxy	In Morgan's Classification, a barred spiral.
cardinal	Angles of the chart that begin with the Equinox and Solstice points of the seasons
canopy	The canopy is the above-ground portion of a plant community formed by plant crowns.
andromeda	A constellation near Perseus and Pegasus.
exchange correlation	The correlation of particles and spins which is embodied in a Slater-determinant wave function
chondrite	A stony meteorite usually characterized by the presence of chondrules (q.v.)
above	1) In vexillology a term used when a charge (or charges) is (or are) placed on top of, or immediately above another – but see ‘above 2)' and ‘surmounted by 1)' (also ‘charge 1)')
early-type emission stars	see Be Stars
quinterfoil	See ‘cinquefoil'.
tropical signs	Cancer and Capricorn; so-called because they occupy parts of the ecliptic where the Sun reaches its farthest point north (Tropic of Cancer) and south (Tropic of Capricorn)
dexter aspect	From the Latin to the right
planum	plateau or high plain.
metar	FRESH WATER
coordinates	Quantities that provide references for locations in space and time
maxwell	The cgs unit of magnetic flux through 1 cm2 normal to a field of 1 gauss
encke's division	(a) Gap within Saturn's Ring A
earth	, the Milky Way is seen edge-on as a swath of patchy white glow in the sky
frequency	the number of repetitions per unit time of the oscillations of an electromagnetic wave (or other wave)
resonant reaction	A nuclear reaction that has an energetically favorable probability of occurring (see resonance capture)
light year	The distance light travels in a vacuum in one year (about 9.5 trillion km/6 trillion miles.)
wind	DIVERGENCE
anti-ferromagnetism	A kind of magnetism found in many solids at low temperatures
pan-slavic/slav colours	The blue, white and red originally adopted by the Slavic peoples during their struggles for independence from the Ottoman and Habsburg empires, and derived from the national flag/civil ensign of the then Russian Empire - but see note below (also ‘core flag’, ‘difference’, 'flag family', ‘pan-African colours’ and ‘pan-Arab colours’ above)."
rutherfordium	Symbol:"Rf" Atomic Number:"104" Atomic Mass: (261)amu One of the postactinide elements
hubble's constant	A constant which defines the relation between an object's recessional velocity and its distance.
green flash	Sometimes, at sunrise or sunset, there are flashes of green light visible near the sun
critical density	Boundary value of mass density between universe models that expand forever (open models) and those that recollapse (closed models)
runge-kutta method	A step-by-step method of numerical integration
valley breeze	MOUNTAIN WAVE
covalent bond	Interaction between atoms by which they "share" valence electrons in the outermost energy shells, thereby filling the outer shell of both atoms involved in the interaction
condensation	A change of state from gas to liquid.
canopus	(a) The brightest star in the constellation Carina and the second brightest star in the night sky
radiation budget	a term used to refer to measurements of the solar radiation (sunlight) coming in to the Earth's surface during the day, and the long wave (infra red) radiation that is radiated from Earth's surface to space at night
orbit	path followed by a star, planet, or satellite around a more massive body.
adiabatic index	The ratio of the fractional change in pressure to the fractional change in density as an element of fluid expands (or contracts) without exchange of heat with its surroundings
geometrodynamics	(a) A theory which attempts to attribute all physical phenomena to properties of spacetime
brightness distribution	A statistical distribution based on brightness, or the distribution of brightness over the surface of an object
resonance line	The longest-wavelength line arising from the ground state
scale length	A measure of the size of a physical system or region of space
space-time	(a) Arena in which events are depicted in the theory of relativity
train	A glow along the path of a meteor which persists for greater than one second, a.k.a
greenwich sidereal date	(GSD) The number of sidereal days elapsed at Greenwich since the beginning of the Greenwich sidereal day that was in progress at Julian date 0.0
extended source	In radio astronomy, formerly a source whose angular extent could be measured, as distinguished from a point source
young	When used to describe a planetary surface "young" means that the visible features are of relatively recent origin, i.e
calendar	The monthly listing of events open to Mensans and their invited guests
altitude-azimuth	(a) Comprising a means of measuring or precisely locating in coordinates the position of objects at any altitude or azimuth
geosphere	HYGROGRAPH
synthesis aerial	A radio interferometer system utilizing a number of small aerials to achieve the effect of an impossibly large single one
molality	A measure of the number of moles of a solute compared to one thousand grams of the solvent
energy	The ability to do work.
volume	A measure of the total space occupied by a body.
low-velocity star	A star whose U, V, and W velocities are all near zero
concavo-convex	Describes a lens with one concave surface and one convex surface
abt	Abbreviation employed in this book to mean After the Beginning of Time, which is here defined as the beginning of the expansion of the Universe
zener diode	A semiconductor diode with high doping levels on each side of the junction
flood tide	The portion of the tide cycle between low water and the following high water
hybrid eclipse	A hybrid eclipse is an annular solar eclipse in which a brief total eclipse occurs in a small region along the eclipse's central path.
reversing current	A tidal current which flows alternately in approximately opposite directions, with slack water at each reversal
arrow of time	The direction, apparently inviolable, of the "flow" of time that distinguishes the past from the future.The direction, apparently inviolable, of the "flow" of time that distinguishes the past from the future
calendar	The listing of events open to all Mensans and their invited guests.
umbra	The region of full shadow that takes place during an eclipse.
lensing	see Gravitational Lensing [C95]
canyon	A large, long split in the ground.
quarantine flag	In current usage, a plain yellow flag (‘Q' Quebec in the International Code of Signal Flags) that is flown by a vessel arriving in port stating that it is healthy and requires medical clearance or free pratique – a pratique flag but see note below (also ‘International Code of Signal Flags').
tithi	The time it takes the angle between the sun and the moon to wane or wax by 12°; used in Indian calendars
eclipse mapping	A technique used to indirectly map the surface of an eclipsing binary star, to look for starspots and make other studies by using Doppler imaging.
ejecta	material from beneath the surface of a body such as a moon or planet that is ejected by an impact such as a meteor and distributed around the surface
bose condensation	a phenomenon occurring in a system of bosons whose total number cannot change, at a temperature of the order of the degeneracy temperature, in which a finite fraction of all the particles begin to occupy a single one-particle state
starlight	The light that is emitted from stars, most of which is beyond the small range of wavelengths (or colors) our eyes can detect
kepler	A German scientist (1571-1630) who used Tycho Brahe's observations of planetary motions to devise three empirical laws now known as Kepler's Laws of Planetary Motion.
erg/sec	= 1e-10 kilowatts.
heterodyne	A detection method used extensively in radio astronomy in which the wave nature of light is used
azimuth	The coordinate which describes an object's location in relation to its compass direction, expressed in degrees between zero and 360.
salt	When you mix an acid and a base, the ionic compounds dissociate
rayonné	See ‘radiant’.
erg	(a) The cgs unit of energy; the work done by a force of 1 dyne acting over a distance of 1 cm
revolution	The motion of one body around another.
solar cycle	The 11-year period over which activity of the Sun, such as sunspots and solar flares, increases and decreases.
tide gauge	A device for measuring the height of tide
inclination of the ecliptic	The Ecliptic is the path of the Sun through the sky as seen from Earth
asymptotic branch stars	Globular cluster stars, which are found in that part of the HR diagram that connects the top pf the giant tip with the horizontal branch
gc or gcc	Gifted Children’s Coordinator, an appointed officer
arrival time	see Dispersion
albedo	This is a measure of how reflective a surface is – the ratio of the amount of electromagnetic radiation (like visible light and infrared) reflected by a surface, to the amount that falls on it.
tornadoes	SEVERE THUNDERSTORM
periapsis	The point in an orbit closest to the body being orbited.
quark	A fundamental particle that makes up hadrons, and has a charge of either 2/3 or -1/3
spontaneous emission	(a) Radiation emitted by an isolated body
equation equinoxes	The Right Ascension of the mean equinox (see Mean Equator; Equinox) referred to the true equator and equinox; apparent sidereal time minus mean sidereal time
part of fortune	The Arabian Part most commonly used by western astrologers
image	A likeness of a thing or a place
i.c.	One of the four major angles of a birth chart
ephemeris	(a) A list or tabulation of astronomical phenomena that change with time
color index	Difference between the photographic and photovisual magnitudes of a star; or more generally, the difference in magnitudes between any two spectral regions
micrometeorites	Extremely small space rocks
datum	Any numerical or geometrical quantity or set of such quantities which may serve as a reference or base for other quantities
galaxy	. Astronomers detect dim but distinct H I radiation at the "21-cm line" with radio telescopes. This is the
mass	a measure of the total amount of material in a body, defined either by the inertial properties of the body or by its gravitational influence on other bodies.
cesium clock	An apparatus used to produce the steady frequency used in defining the second
fractal	(a) A geometric figure in which a pattern is repeated ad infinitum on smaller and smaller scales
mass of the galaxy	The mass has been assessed at various galactocentric distances: At R = 9 kpc, M = 1.0 × 1011 Solar masses
glycerol	Glycerol is a biological compound that has three carbons with three alcohol functional groups
h i region	Region of neutral (atomic) hydrogen in interstellar space
b-type star	Having a spectral type of B, that is, hot and blue, such as Rigel and Regulus
cloud chamber	A glass-walled enclosure containing a vapor in which particles can be detected by photographing the tracks of water droplets they leave behind when they pass through the chamber
fnmoc	Fleet Numerical Meteorology and Oceanography Center
longitude	Angular distance along a parallel, calculated from a source meridian in a system of spherical coordinates.
mantling	A heraldic term for the decoration resembling drapery in a coat of arms, and attached to the helmet by a torse (see also ‘Appendix IV’, ‘armorial bearings’, ‘coat of arms’ and, ‘helm’ – for information on torse see ‘wreath 2)’).
frontolysis	FRONTOLYSIS
celestial meridian	The Celestial Meridian - or "the Meridian" - is an imaginary line that runs from the South Celestial Pole through the zenith to the North Celestial Pole
crystal twinning	Crystal twinning occurs when two crystals grow in different directions and eventually intersecting
standstill	An interval in the cycle of a variable star during which the brightness temporarily stops changing
inverse square law	A force law that applies to the gravitational and electromagnetic forces in which the magnitude of the force decreases in proportion to the inverse of the square of the distance
manganese stars	Stars with an anomalously high mn-fe ratio, which show deviations from the odd-even effect for phosphorus, gallium, and yttrium
mean motion	In undisturbed elliptic motion, the constant angular speed required for a body to complete one revolution in an orbit of a specified semi-major axis
anamorphic magnification	The difference in magnification along the spectrum and perpendicular to the spectrum in a spectrograph
limb	(a) Apparent edge of the disk of a Solar System body as projected on the sky
in saltire	The heraldic term used when two separate objects or charges are placed across each other diagonally on a flag, shield or banner of arms - saltirewise (see also ‘banner of arms', ‘saltire’ and ‘per saltire’.
ssr	Satellite System Receiver
galaxy	A nebula can be observed in regions where new stars have recently been born and around stars that are dying or have died
astrologer	One who practices astrology; a professional spook
galaxy	A system of millions or billions of stars and interstellar gases and material, held together by gravity.
terminal velocity	The steady final velocity reached by a body in a fluid when the resultant force on it is zero.[DC99]
navy flag	See ‘branch of service flag’ (also ‘armed services flag’).
molybdenum	Symbol:"Mo" Atomic Number:"42" Atomic Mass: 95.94amu
circle	The astrological symbol in casting for a "higher" or "spiritual" self.
centre of gravity	The point in a body, or system of bodies, at which all external forces can be taken to act
impact melt spherule	spherules of shock-melted rock ejected from an impact crater
truncated julian date	abbr
supernumeraries	These are the faint rainbow bands seen on the inner edge of a rainbow
penumbra	The lighter shadow cast by an eclipsing body during a partial eclipse; also the outer region of a sunspot group.
luminosity	that indicates energy output, or visual magnitude that indicates measured luminosity expressed on the magnitude scale.
temperature	The temperature of a star as estimated from the intensity of the stellar radiation at two or more colors or wavelengths.
transmit	To send from one person or place to another
subgroup	These are columns of transition and inner transition elements
celestial sphere	The sky envisioned as a (hemi)sphere at infinite focus
anti-baryon	The antiparticle of a baryon
orion arm	The Orion Arm (also called the Local Arm) is the arm of the Milky Way Galaxy where our solar system is located.
regulus	A visual triple B8 V star about 26 pc distant
vacuum higgs value	The value that the Higgs field(s) have in the vacuum
selected areas	262 small (75' square) regions of the sky in which magnitudes, spectral types, and luminosity classes of stars have been accurately measured and which have served as standards for magnitude systems
shoreline	The line where shore and water meet
caldera	a large, basin-shaped volcanic depression that is more or less circular in form
convection	One of three modes of transmission of heat (energy) from hot regions to cold regions; involves motions of masses of material.
skylight	The faint, diffuse glow of the night sky
tektites	Objects made from natural glass that are created from the impact of meteorites
storms	SNOW DEVIL
fan	A semi-circular patriotic decoration in bunting, usually (but not invariably) of flag design and/or colours - a swag (see also ‘bunting 2)’ and ‘mourning bunting').
hubble constant	A measure of the rate of expansion of the Universe; current estimates are about 70 km/s/megaparsec.
scalar-tensor theory	A class of theories of gravity more complex than Einstein's theory, general relativity
light clock	A hypothetical clock that measures elapsed time by counting the number of round-trip journeys completed by a single photon between two mirrors
kommandowimpel	See ‘masthead pennant 1)’.
bose statistics	the form of statistics applicable to bosons
telegraph flag	In British RN usage now obsolete, the flag invented by Admiral Popham and raised prior to a signal hoist to indicate whether the following flags were to be deciphered using a signal book or by his vocabulary code (see also ‘code pennant', 'preparative' and ‘signal flag').
praseodymium	Symbol:"Pr" Atomic Number:"59" Atomic Mass: 140.91amu
active optics	Corrects distortions in the shape of large, thin primary mirrors due to gravitational and structural flexing to provide a smoother surface
height of tide	Height of tide is the vertical distance between the surface of the sea and Chart Datum
spectrograph	an instrument that spreads light or other electromagnetic radiation into it's component wavelengths (spectrum), recording the results photographically or electronically.
scaling	(a) The phenomenon observed in deep inelastic scattering, and predicted by James Bjorken, whereby the structure functions which describe the shape of the nucleon depend not on the energy or momentum involved in the reaction, but on some dimensionless ratio of the two
solar minimum	The period when the activity of the Sun and the number of sunspots are lowest.
resonance	(a) One of the natural states of oscillation of a physical system
umbra	The part of the shadow cast by an eclipsing body that results from the Sun being totally eclipsed.
symmetry principle	A principle that requires a physical system to have a symmetry
empiricism	An emphasis on sense data as a source of knowledge, in opposition to the rationalist belief that reasoning is superior to experience
abeyance	See ‘in abeyance'.
weak g-band stars	A G-type giant (G5 to K5) with a very weak or absent G band of CH and weak CN bands
iers	International Earth Rotation and Reference Systems Service
l-magnitude	The magnitude derived from observations at an infrared wavelength of 3.5 microns
water signs	Cancer (cardinal), Scorpio (fixed), Pisces (mutable)
flat field	An exposure taken of a constant source to counteract pixel variations in a CCD image
ellipse	A flattened circle
bellatrix	A B2 III star 80 pc distant
chondrules	Small spherical grains varying from microscopic size to the size of a pea, usually composed of iron, aluminum, or magnesium silicates
metastable state	(a) A condition of a system or body in which it appears to be in stable equilibrium but, if disturbed, can settle into a lower energy state
station	A planet is said to "make a station" at the degree it occupies when it appears motionless as its direction changes from direct to retrograde or vise versa.
saros cycle	The eighteen-year (approximate) cycle, containing an average of forty-one solar eclipses and twenty-nine lunar eclipses, in which an eclipse from each current Saros Series appears.
saint james’ cross	See ‘cross of Santiago’ in ‘appendix VIII’.
covariant	An adjective applied to a set of relationships between mathematical or physical quantities if they remain unchanged after transformation to a different coordinate system
magnetic monopole	(a) A hypothetical particle that carries an isolated north or south magnetic pole
nativity	A natal horoscope.
raguly	A heraldic term meaning any number of small regular projections set an angle on both sides (or on one side only) of a bar, cross or saltire and thought to represent a roughly trimmed branch – see ‘ragged cross' (also ‘saltire').
geosphere	LONGITUDE
sedimentation	Sedimentation in the ocean is the tendency of particles in suspension or molecules in solution to settle out towards the ocean floor
fluorine	Symbol:"F" Atomic Number:"9" Atomic Mass: 19.00amu
et	Ephemeris time, a measurement of time defined by orbital motions
axisymmetric collapse	Collapse of mass in such a way that the mass maintains the symmetry of a cylinder
kaluza-klein theory	(a) Class of theories incorporating extra curled-up dimensions, together with quantum mechanics
reception	Shortened form of mutual reception
hassium	A transactinide element formed artificially
wavelength	the distance from crest to crest or trough to trough of an electromagnetic wave (see electromagnetic radiation) or other wave.
right ascension	The angle, measured eastward on the celestial equator, between the First Point of Aries and the hour circle through the object.
lanthanum	Symbol:"La" Atomic Number:"57" Atomic Mass: 138.91amu
antipodal point	the point that is directly on the opposite side of the planet
ozone layer	STRATUS
imperial dragon flag	See ‘dragon flag 2)’.
actinium	A soft silvery-white radioactive metallic element that is the first member of the actinoid series
eccentricity	The measure of the degree to which an ellipse is not circular; ratio of the distance between the foci to the major axis
apoapsis	Point in orbit furthest from body it is orbiting.
super-metal-rich	Used in reference to stars, or stellar populations, which are richer in metals than the Hyades.
celestial sphere	The celestial sphere is an imaginary sphere with a very large radius whose centre is the centre of the Earth
helium-strong stars	B-type stars in which the helium lines are stronger than in normal stars
meteor	Also called a "shooting star," when a small piece of space debris enters Earth's atmosphere and burns up from the friction with the air molecules.
schwarzschild filling factor	Ratio of the actual density to the limiting value for a system
current meter	An instrument for measuring the speed and direction, or just the speed of a current
arcminute	One sixtieth of a degree of angular measure
type iia string theory	One of the five superstring theories; involves closed strings with left-right symmetric vibrational patterns
angular size	A measure of the apparent size of an object in the sky, measured in angles.
exalted	The term used to describe a planet that is placed in its sign of exaltation, the sign, other than its one of dignity (natural rulership), in which it functions most smoothly because of the harmonious relationship between planet and sign.
multi-doughnut	Also, Multi-Handled Doughnut
galaxy correlation function	A measure of the degree of galaxy clustering in a large sample of galaxies
spatial dimension	any of the three dimensions that are space-like - that is, any except the time dimension (i.e
moiré fringes	The pattern obtained when two regular sets of lines or points overlap
ultra-high frequency	UHF A radio frequency in the range between 3 GHz and 0.3 GHz (wavelength 10 cm-1 m)
limb	the edge of the apparent disc of a celestial object
right ascension	Measurement along the celestial equator eastward from 0° Aries that describes planetary positions in terms of degrees, minutes and seconds, not zodiacal signs
induction	A logical method for drawing a broad conclusion from a limited set of observations or experiments
baroclinity	BARRIER WINDS
electromagnetic unit	EMU A system of electrical units based on the electromagnetic properties of an electric current
r zones	Regions in the solar corona in which short-lived radiofrequency variations are observed
ovla	Optical Very Large Array
closed space	A space of finite volume but without any boundary (in the cosmological context)
longitude of the perihelion	For a Solar System body, the longitude of the ascending node plus the angle along the orbit from the node to the perihelion point
parsecs	Kirkwood Gaps Regions in the main belt of asteroids where few or no asteroids are found
head	See coma
fan’s flag/pennant	See ‘sports flag 2)’.
standard candle	A star with a known luminosity dependence that can be used to calculate cosmological distances.
plage	Bright regions in the Sun's chromosphere.
crt	Cathode ray tube video display device.
semi-diameter	The angle at the observer subtended by the equatorial radius of the Sun, Moon, or a planet
medical astrology	The branch of astrology devoted to the study of the human body, disease and health according to astrological symbolism portrayed in a horoscope.
time dilation	Feature emerging from special relativity in which the flow of time slows down for an observer in motion
eventuality	a contingency concerning a system which is either true or false if it is definite, but which (in view of a fundamental conceptual innovation of quantum mechanics) may he indefinite
labyrinthus	intersecting valley complex.
interval	(a) The quantity in Minkowski space-time which replaces length in ordinary space
lense-thirring effect	The precession of the plane of the geodesic orbit of a test particle around a rotating mass in general relativity
protactinium	Symbol:"Pa" Atomic Number:"91" Atomic Mass: 231.04amu
ecclesiastic flag	See ‘Christian flag 1)’.
hamiltonian operator	The dynamical operator in quantum mechanics that corresponds to the Hamiltonian function in classical mechanics
beryllium	Symbol:"Be" Atomic Number:"4" Atomic Mass: 9.01amu
garbe	The heraldic term for a sheaf of wheat or corn.
led	Light-Emitting Diode -- A semiconductor diode, made from certain materials (e.g
chromatic aberration	An unwanted effect seen in refracting telescopes, caused by the fact that different wavelengths of light are refracted by different amounts by the lens and so are focussed at slightly different places
magnification	The effect of an optical system on the apparent angular size of an object
saa	South Atlantic Anomaly
sextile	The sixth harmonic, 60°; a major easy aspect considered beneficial and opportune.
earth	. Astronomers cleverly use these observations to calculate
mean anomaly	The anomaly which would exist if a planet orbited at a uniform speed in a circular orbit.
force	A reaction between two or more bodies which tends to affect the physical relationship between them, such as their motion or position.
s-state/s-level	The state of an atom in which the orbital angular momentum L (the vector sum of the orbital angular momenta l of the individual electrons) is zero
comparison band	The wavelength interval measured in the continuum outside a spectral feature - e.g., the 21-cm line
electron gas	a system of electrons whose mutual interactions are sufficiently weak that they can be regarded as moving independently, subject only to the effects of the exclusion principle
cosmecology	The science that considers Earth in its relationship to celestial phenomena.
electron geometry	Structure of a compound based on the arrangement of its electrons.
albedo	the ratio of the amount of light reflected by an object and the amount of incident light; a measure of the reflectivity or intrinsic brightness of an object (a white, perfectly reflecting surface would have an albedo of 1.0; a black perfectly absorbing surface would have an albedo of 0.0).
systematic error	Error that cannot be reduced by simply increasing the number of observations
fissure	a narrow opening or crack of considerable length and depth.
naiant	See ‘appendix V’.
bias	(a) A potential applied to an electrode in an electronic device to produce the desired characteristic
dorsum	ridge.
local hypothesis	The hypothesis that quasars are not at the distances inferred from their redshifts
lyman alpha line	The characteristic spectral line of atomic hydrogen associated with its lowest excited state
even-odd nuclei	Nuclei that contain even numbers of protons but odd numbers of neutrons
cen a	Centaurus A Strong radio source
dendritic habit	A dendritic habit describes the shape of a large group of crystals that looks like the branching of veins or a plant.
fraunhofer diffraction	Diffraction observed with incident parallel light
stratosphere	the cold region of a planetary atmosphere above the convecting regions (the troposphere), usually without vertical motions but sometimes exhibiting strong horizontal jet streams.
line of nodes	line between the two
warm high	COLD LOW
horizon	The line marking the apparent junction of Earth and sky.
isoelectronic sequence	A sequence of ions which have the same number of electrons but different atomic numbers
electromagnetic force	A fundamental force that influences anything which carries a charge
progressions	The general term applied to any method of advancing the planets and house cusps of a natal horoscope to a particular time after birth.
pcd	Product Confidence Data, a coded set of quality flags generated at various stages of data processing.
carbonaceous chondrite	a type of primitive chondrite with evidence of nebular processes.
vibrational pattern	The precise number of peaks and troughs as well as their amplitude as a string oscillates
aneretic degree	The final degree of a sign (29th)
star counts	Determination of the number of stars in a region of the sky as a function of apparent magnitude and sometimes color
gay pride flag	See 'rainbow flag 1)'.
medium coeli	From the Latin, literally middle of the heavens; the culminating degree of the ecliptic, commonly called Midheaven, abbreviated MC
local thermodynamic equilibrium	LTE -- The assumption that all distribution functions characterizing the material and its interaction with the radiation field at a point in the star are given by thermodynamic equilibrium relations at local values of the temperature and density
departing aspect	An aspect in which the direction from significator to promittor is backward in the zodiac (clockwise in a horoscope)
coriolis force	Composite centrifugal force, due to the rotation of the Earth, which acts on moving particles, whose motion is considered relative to that of the Earth.
hubble constant	The relationship between the distance of an object and the speed at which it is traveling away from us
cesium	Symbol:"Cs" Atomic Number:"55" Atomic Mass: 132.91amu
cd-rom	Compact Disk - Read Only Memory A computer data storage technology
biconcave	Describing a lens with two concave faces
insoluble	An insoluble substance is one that is not able to dissolve in another substance
stellar populations	Large collections of stars that share properties of age, motions, or chemical composition.
iron	it is only naturally created in supernova explosions and similar cosmic events.
in base	The heraldic term used when a charge or charges appear in the lower part of a shield, banner of arms or flag that is otherwise undivided – see ‘base 1)’ (also ‘abased', ‘banner of arms', and ‘shield’).
jpl	Jet Propulsion Laboratory, operating division of the California Institute of Technology.
equivalence principle	(a) The principle that it is impossible to distinguish between gravitational and inertial forces; gravitational mass is precisely equal to inertial mass
endothermic	Process that absorbs heat from its surroundings as the reaction proceeds.
color-magnitude diagram	Plot of absolute or apparent visual magnitude against color index for a group of stars
kepler's third law	The square of the period of a planet's orbit is proportional to the cube of that planet's semi major axis; the constant of proportionality is the same for all planets.
gaussian noise	Random fluctuations in an otherwise smooth distribution of something
rac	Reflective Acoustic Coupling; a type of surface acoustic wave device in which the acoustic signal undergoes a reflection.
quintile	An aspect of 72 degrees
exponential notation	"1.23e4" means "1.23 times 10 to the fourth power" or 12,300; "5.67e-8" means "5.67 divided by 10 to the eighth power" or 0.0000000567.
rima	a fissure.
sigma	In astronomy, a quantitative measure of the random speeds of stars in a collection of stars
julian date	the interval of time in days and fraction of a day since 1 January 4713 BC, Greenwich noon.
equation of state	(a) A relation between the pressure, temperature, and density of a fluid
graph	A graph is a diagram that represents a series of points or lines.
floaters	Debris that floats in the liquid inside the eye
celestial poles	the Earth's north and south poles projected onto the sky
conservation laws	Laws that identify a quantity, such as energy, that remains unchanged throughout a transformation
catalog equinox	The intersection of the hour circle of zero right ascension of a star catalog with the celestial equator
teutonic cross	See ‘cross-potent’ in ‘appendix VIII’.
gaunt factor	A quantum-mechanical correction factor applied to the semiclassical Kramers formula for photon absorption
vertical tricolour	See ‘tricolour 1)’ and ‘tricolour 2)’.
laminar air flow	This is where air flows smoothly in layers, without any interference to disrupt the flow
solar cycle	The 11-year variation in sunspot activity.
reflection	The deflection or bouncing of electromagnetic waves when they encounter a surface.
homogeneous	Uniform in composition throughout the volume considered.
old style	used to designate the
neutrons	Although the radiation exposures occurred in the forties, radiation induced cancers are still occurring among A-bomb survivors.
singularity	(a) Anomaly in space-time at which a state not in accord with the classical laws of physics obtains
flexus	cuspate (pointed) linear feature.
sunspot	Dark patches on the Sun's surface caused by a temporary cooler region than the surrounding areas.
semi-square	The eighth harmonic, 45°; an important minor hard aspect in which planetary energies do not merge harmoniously but produce friction.
crescent	a phase of the Moon or other planetary object when it is less than half illuminated as seen by the observer
siberian high	SUBREFRACTION
complex number	A type of number that is the sum of two parts, the first of which produces a positive number when multiplied by itself (like ordinary numbers), and the second of which produces a negative number when multiplied by itself (unlike ordinary numbers)
curled-up dimension	A spatial dimension that does not have an observably large spatial extent; a spatial dimension that is crumpled, wrapped, or curled up into a tiny size, thereby evading direct detection
exchange interaction	the spin-dependent part of the interaction between particles with spin
pressure tendency	ISOBAR
critical degrees	the places of certain fixed stars regarded as of particular importance; also the Cusps of the Lunar Mansions.
limb	The outer edge of the disc of a celestial body.
spectral lines	(a) Dark lines visible in an absorption spectrum, or bright lines that make up an emission spectrum
doppler effect	the apparent change in wavelength of sound or light emitted by an object in relation to an observer's position
inverse bremsstrahlung	Absorption (free-free absorption) of a photon by an electron in the field of a nucleus.[H76]
celestial sphere	A hypothetical sphere of very large radius centered on the observer; the apparent sphere of the night sky.
eri	see Achernar
caltrap	The heraldic term for a three or four-armed (usually but not invariably faceted) figure that represents an implement of war consisting of four spikes which, when thrown on the ground, always has one point facing upwards, and designed to injure horses – a caltrop, calthrop, cheval-trap or galtrap (see also ‘faceted').
placidean houses	The house system devised by the Spanish monk, Placidus de Tito (seventeenth century)
naval ensign	See under ‘ensign’.
magnetic moment	(a) A measure of the extent to which a physical system (e.g
sublimation	A direct change of state from solid to vapor without melting
differentiation	The separation of heavy matter from light matter, thus causing a variation in density and composition
yod	A powerful aspect.
spectral index	The power of the frequency to which the intensity at that frequency is proportional
lagrange point	A unique point in the plane of two orbiting bodies where a third body experiences no forces and can remain effectively motionless in equilibrium.
haze	LITHOSPHERE
decanate	The division of each sign into three equal parts of 10 degrees each.
atmosphere	KELVIN TEMPERATURE SCALE
standard error	The standard deviation of a distribution of means or any other statistical measure computed from samples
aliasing	In a discrete Fourier transform, the overlapping of replicas of the basic transform, usually due to undersampling
aat	Anglo-Australian Telescope
approaching aspect	An aspect in which the significator is moving toward the promittor in natural order of the zodiac (direction from significator to promittor is counterclockwise in a natal horoscope)
charge conjugation	The technical term for mathematical operations which interchange particles and antiparticles
soft x-ray	primarily because of difference in observation techniques.
schwarzschild singularity	The center of a black hole
angular dispersion	The rate of change of angle (due to refraction or diffraction) with wavelength of the emergent beam in a spectrograph
auroral corona	An auroral corona usually appears during energetic auroral displays
solar cycle	the approximately 11-year quasi-periodic variation in frequency or number of solar active events
equatorial plane	The plane that passes through the centre of a body and is perpendicular to that body's axis of rotation.
lindblad resonance	A resonance hypothesized by Lindblad in the 1920s in his attempt to explain the existence of spiral arms (see Density Wave Theory)
aphelion	the outermost point in a solar orbit
lallemand camera	A very early form of image tube.
astronomical twilight	the time of morning or evening when the sun is 18° below the horizon
atmosphere	STANDARD SURFACE PRESSURE
open star cluster	A cluster of stars usually containing several hundred members packed into a region usually less than 20 light years in size
anti-matter	(a) For every variety of particle there exists an antiparticle with opposite properties such as sign of electrical charge
hydrodynamics	The study of how gases and fluids flow under applied forces
valence electron	In an atom, an electron in an incompletely filled (usually outer) shell, available for chemical bonding to form a molecule
hyleg	Interchangeable with Apheta
flat	Subject to the rules of geometry codified by Euclid; a shape, like the surface of a perfectly smooth tabletop, and its higher-dimensional generalizations
proctor:	The person responsible for administering the Mensa admission tests.
penumbra	Literally partial shadow; the partially lighted area around any completely darkened area (umbra) of full shadow.
metar	HALO
horizon	(a) The maximum distance that an observer can see
soft tissue pump	The soft tissue pump is the net downward flux of carbon associated with the transport of organic matter from the surface layer where it is produced, to the deeper layers where it can be remineralised
large-scale motions	Bulk motions of distant galaxies deviating from the Hubble flow
noise	Noise is a disturbance that obscures or reduces the clarity of a signal.
circumpolar stars	stars that never set when seen from a given location
ekman layer	Upper boundary layer within which the amplitude changes exponentially
theory of everything	A "Theory of Everything" would not only describe how thing s work but also explain why things are the way they are
rupes	scarp.
scopulus	lobate or irregular scarp.
homogeneity problem	Same as horizon problem
retrograde	westward motion in the sky
ecliptic co-ordinates	A system of celestial co-ordinates that uses the ecliptic as the reference plane and the First Point of Aries as the reference direction
kirkwood gaps	regions in the main belt of asteroids where few or no asteroids are found
earth	, and thousands litter the surface of the
vernal	From the Latin vernus, belonging to spring; of or pertaining to spring
absolute zero	The coldest possible temperature, at which all molecular motion stops
cold emission	Emission of electrons from a solid by a process other than thermionic emission
schmidt telescope	(a) A telescope with a spherical primary mirror and a thin refractive corrector plate with a complex, non-spherical shape
refractory grain	A grain that has been formed at high temperatures
metonic cycle	19-year cycle employed in
autumnal equinox	VERTICAL TEMPERATURE PROFILE
atmosphere	The air all around Earth.
severe weather	CAPE VERDE ISLANDS
geocentric	Measured or viewed in relation to Earth as the reference or observation point; Earth-centered measurements.
comet	An ice-rich interplanetary body that, when heated by the Sun in the inner solar system, releases gases that form a bright head and diffuse tail
wind	DRIZZLE
compound	A substance composed of two or more atoms bound by chemical forces.
solstice	the time of the year when the Sun appears furthest north or south of the celestial equator
cosmic rays	X-ray Astronomy The field of astronomy that studies celestial objects by the x-rays they emit.
gamma ray	the highest energy (shortest wavelength) photons in the electromagnetic spectrum
condensation sequence	The sequence in which chemical compounds condense to form solid grains in a cooling, dense nebula.
fermi constant	The parameter that fixes the strength with which the weak force couples to particles of matter in Fermi's original theory of the weak interaction
ultraviolet	Region of the electromagnetic spectrum just beyond the visible range, corrosponding to wavelengths slightly shorter than blue light.
radiation temperature	The temperature that a blackbody of similar dimensions would have that radiated the same intensity at the same frequency
action-at-a-distance	A description of a force, such as Newton's law of gravity, in which two separated bodies are said to directly exert forces on each other
handsigne	A 16th/17th Century variant spelling, now obsolete, of ensign – see ‘ensign 1)’ and ‘ensign 4)’ (also 'ancient 2)').
meridian	An imaginary great circle on the celestial sphere
cobe	COsmic Background Experiment: Satellite used to study the microwave background
latitude	Angle between the Equator and a point on the surface of the Earth
slac	The acronym for the Stanford Linear Accelerator Center at Stanford University in California, USA
field	(a) A physical quantity, like the electric or magnetic field, which varies from point to point in space
radiation pressure	The transfer of momentum by electromagnetic radiation incident on a surface: prad = (4/3)T4 / c
cassini-huygens mission	Planetary mission designed to explore in detail the Saturnian system (see http://saturn.jpl.nasa.gov/home/index.cfm and http://www.esa.int/esaMI/Cassini-Huygens/index.html)
wolf-rayet stars	are hot, blue giants
chandrasekhar limit	A mass of about 1.4 solar masses, the maximum for white dwarfs; stars of greater mass have too great a central pressure, causing formation of a star type denser than a white dwarf.
hologram	An interferometric method of recording information about the three-dimensional nature of an object which relies on preserving both the amplitudes and phases of the wavefronts which reach the detector, instead of merely the amplitudes
solar system	Compared with other stars it is fairly average in terms of size and temperature
compact hii region	A dense (ne 103 cm-3) H II region of small linear dimensions ( 1 pc)
corona	ovoid-shaped feature.
frequency	(a) The frequency of a periodic or harmonic motion which repeats itself in equal time units is the number of oscillations or cycles per unit of time
conduction band	(a) In an insulator or semiconductor this is the lowest empty energy band, and electrons excited to the conduction band can carry current
proctor	A member who administers the Mensa admission test to prospective members; must have a 4-year degree
birefringent	Also birefringence
radio astronomy	the astronomy associated with radio observations of celestial objects
axis	The imaginary line through the middle of a rotating object around which the object spins.
-process	A hypothetical process of nucleosynthesis (now considered obsolete terminology), which consisted of redistributing -particles in the region from 20Ne to 56Fe (and perhaps slightly higher)
persistent train	A glow along the path of a meteor which persists for greater than one second
dsms	Deep Space Mission System, the system of computers, software, networks, and procedures that processes data from the DSN at JPL.
trigonal crystal	A trigonal crystal has a shape that has three sides and no specific length
stellarator	A type of plasma machine
flare	rapid release of energy from a localized region on the Sun in the form of electromagnetic radiation, energetic particles, and mass motions.
spallation	The process in which an incoming beam of particles or energy collides with a substance, reacts with it, and knocks off pieces of it
solar day	SKEW T-LOG P DIAGRAM
bench mark	A permanent, stable object containing a marked point of known elevation with respect to a datum used as a reference level for tidal observations or as a control point for levelling
isotope	A variation of a chemical element with more neutrons in the atmoic nucleus; usually radioactive.
zigzag	See ‘serrated 2)'.
solar burst	see Burst [H76]
nws	NAUTICAL MILE
limb	Luminous edge of the disk of a heavenly body.
windward	LENTICULAR CLOUD
metric tensor	the mathematical object that describes the deviation of Pythagoras's theorem in a curved space
iau	International Astronomical Union
accuracy	The difference between a true value and a measurement
general relativity	This is Einstein's theory of gravity, which states that mass and energy curve space-time – the fabric of the Universe
supernova remnant	(a) SNR The expanding shell of gas ejected at a speed of about 10,000 km s-1 by a supernova explosion, observed as an expanding diffuse gaseous nebula, often with a shell-like structure
critical density	The density that just stops the expansion of space, after infinite cosmic time has elapsed
vent	the opening in the crust through which volcanic material erupts.
naval crown	A crown generally (but not exclusively) formed from the sterns and square sails of ships placed upon a circle or fillet, and loosely based on an ancient Roman triumphal ornament of the same name (see also ‘civic crown’, ‘crown’, ‘fillet 3)', ‘mural crown’ and ‘yachting crown').
caldera	A large volcanic collapse crater that may be a few km across.
c3 plants	Plants that photosynthesize by the Calvin cycle
right ascension	A component of the coordinate system used to designate positions on the celestial sphere
duality	a correspondence between apparently different theories that lead to the same physical results
marks of cadency	See ‘cadency, mark of'.
palladium	Symbol:"Pd" Atomic Number:"46" Atomic Mass: 106.40amu
seiche	A standing wave oscillation of an enclosed or semi-enclosed water body that continues, pendulum fashion, after the cessation of the originating force, which may have been either seismic, atmospheric, or wave induced.
hartle-hawking proposal	See no-boundary proposal
neptunium	Symbol:"Np" Atomic Number:"93" Atomic Mass: 237.05amu
line of nodes	The line along which the plane of the Moon’s orbit intersects the plane of the ecliptic.
boltzmann-saha theory	A theory describing the distribution of atoms of partially ionized matter over possible excitation and ionization states, in the limit of low density (see Thomas-Fermi theory)
iapetus	The ninth satellite of Saturn, about 850±100 km in radius; period 79d7h55m, e = 0.028, inclination to Saturn's orbital plane 14°.7
mile	The mile employed in this book is the statute mile, equal to 5,280 feet
lord	An antiquated term synonymous with planetary ruler.
adaptation	The structure, process, or behavior that helps an organism survive and pass its genes on to the next generation.
tropical zodiac	The circle of signs that follows the apparent path of the Sun (ecliptic)
copenhagen interpretation	(a) In quantum mechanics, the interpretation of the wave-function as a description of the probabilities that the state of the system will take on different values
tectonics	The movement of plates of planetary crust that causes continental drift on Earth, as well as volcanoes and earthquakes.
millibar	A measure of atmospheric pressure equal to 1/1000 of a bar
kirkwood gaps	Regions in the main belt of asteroids where few or no asteroids are found
chaos	distinctive area of broken terrain.
oceanus	literally "ocean"; really a large circular plain
gps radio source	Gigahertz Peaked Spectrum A class of powerful compact extragalactic radio sources characterized by an overall turnover in their radio spectra at about 1 GHz in frequency.
entropy	(a) A thermodynamic property of a macroscopic body which corresponds intuitively to the degree of disorder
orbit	The path of one body around another
south atlantic anomaly	the region over the South Atlantic Ocean where the lower Van Allen belt of energetic, electrically charged particles is particularly close to the Earth's surface
ionic bond	A chemical bond between two atoms where one or more electrons are passed from one atom to another
water vapor	HYGROMETER
superpartners	(a) Particles whose spins differ by 1/2 unit and that are paired by supersymmetry
kev	one thousand electron volts.
sedr	Supplementary Experiment Data Record.
hanning method	A method of smoothing out the noise in radio data
instability strip	A region in the Hertzsprung gap (q.v.) occupied by pulsating stars in a post-main-sequence stage of stellar evolution
make her number	(v) To hoist that group of signal flags which identify a ship in a recognized code code – a term now increasingly obsolete – see ‘call sign hoist’ and the note below (also ‘International Code of Signal Flags’, ‘pendant number’, ‘private signal 3)’ and ‘signal flag’).
ephemeris hour angle	An hour angle referred to the ephemeris meridian
continental drift	The movement and formation of continents over long periods of time due to plate tectonics.
anharmonic oscillator	A system whose vibration, while still periodic, cannot be described in terms of simple harmonic motions (i.e
uhf	Ultra-High Frequency A radio frequency in the range between 3 GHz and 0.3 GHz (wavelength 10 cm-1 m)
structure	Objects have structure if they have parts - that is, if they are made of other things
radiosonde	A sounding balloon used to transmit information on Earth's upper atmosphere
cosmology	The scientific study of the formation, evolution and structure of the universe.
supersymmetric quantum field theory	Quantum field theory incorporating supersymmetry
coaxial cable	A type of electrical wiring
atoms	This results in ions, that are electrically charged atoms, positive when electrons have been lost, or negative when electrons have been added.
singularity	the center of a black hole; a point (or ring) of infinite density that occupies zero space
gray body	A body whose emissivity is constant and less than unity
commutation relations	in quantum mechanics, if one has two operators A and B, then it is often the case that the action of the product operator AB is not the same as that of BA
carinae	A peculiar nova-like variable about 2 kpc distant
carboxyl group	Carboxyl groups are chemical functional groups with one carbon, one hydrogen, and two oxygen atoms (COOH)
observation	PREVAILING WIND
separating aspect	One in which the significator (faster moving planet of the two in aspect) is moving away from partile (the degree at which the aspect is exact).
albedo feature	A dark or light marking on the surface of an object that may not be a geological or topographical feature.
canonical change	A periodic change in one of the components of an orbit (cf
zenith	Is the point directly overhead on the celestial sphere.
lattice gas	A model of a condensed system in which atoms may be present on or absent from the sites of a lattice, but no movement of the sites or distortion of the lattice is allowed.[D89]
vorticity	VORTICITY
rvc	Regional Vice-Chair: Elected by and for a geographic region of Mensa, this officer represents that region on the AMC and works to foster growth and development within the region
tri-septile	A seldom-used minor aspect, probably inharmonious, belonging to the septile (seventh harmonic) family; separating distance, 154°17'.
height	Elevation above ground or distance upwards from a given level (especially sea level) to a fixed point
asteroid	Millibar A measure of atmospheric pressure equal to 1/1000 of a bar
semi-major axis	Half the length of the major axis of an ellipse; a standard element used to describe an elliptical orbit
colles	small hills or knobs
narrow pennant	See ‘masthead pendant’.
horizon	The line marking the apparent junction of Earth and sky
carbohydrate	A class of modular molecules made from carbon, hydrogen, and oxygen that form the solid structure of living things and play a central role in how living things acquire oxygen.
energy curve	A plot of the intensity of the continuous spectrum versus the wavelength
wavefront	A continuous surface associated with a wave radiation, in which all the vibrations concerned are in phase
isotope	Isotopes are atoms of the same element that have different atomic masses
deoxyribonucleic acid	Abbreviated as DNA, this long molecule in the shape of a double helix is the keyto life
vastitas	widespread lowlands
mesosphere	The part of Earth's atmosphere immediately above the stratosphere, where the temperature drops from about 270 K to 180 K
density	measure of an object?s mass in relation to how much space it occupies.
parallax	The apparent displacement or the difference in apparent direction of an object as seen from two different points not on a straight line with the object (as from two different observing sites on earth)
carbon monoxide	A molecule consisting of one carbon atom and one oxygen atom (CO)
lunarplanetins	Planetary Surface Instrument Workshop Report
barn	(a) Symbol: b A unit of area defined as 10-28 square meter
focal plane	Prime Meridian: The polar great semi-circle adopted as the reference direction for measurement of longitude
cygnus x-3	An X-ray binary with a 4.8 hour period discovered in 1966
language flags	See ‘linguistic flags’.
rocket	A vehicle that burns fuel and shoots the flaming gases out one end (the engine) to move in the opposite direction
convection	In thermal convection, some of a fluid (liquid or gas) receives heat
freezing	FROZEN PRECIPITATION
holomorphic	Same as complex analytic
copper	Symbol:"Cu" Atomic Number:"29" Atomic Mass: 63.55amu
colloid	A substance containing very small particles (sizes in the range 10-9-10-5 m)
vacuum expectation value	The value of the Higgs field (a constant value different from zero) is called a system's Vacuum Expectation Value
metar	SNOW ADVISORY
ch stars	G-type giants (G5 to K5) in which the molecular bands of CH are very strong
gamma-ray	burst A random burst of energy from distant objects in the form of gamma rays
nocturnal arc	The time expressed in right ascension that it takes a planet or degree of the zodiac to move from its setting point on the horizon to its rising point.
longitude	The angular distance east or west, between the meridian of a particular place on Earth and that of the Prime Meridian (located in Greenwich, England) expressed in degrees or time.
crystal habit	The general form a crystal takes
zenithal hourly rate	The number of meteors during a meteor shower that an observer at a dark site would see during the course of an hour with the radiant overhead.
blooming	A method of coating lenses to reduce back-reflection from their surfaces
solstice	Either of two points on the ecliptic at which the Sun reaches it farthest point north (0° Cancer) or south (0° Capricorn) of the equator
transuranic elements	Elements that have a proton number greater than 92 (i.e
cds	Coronal Diagnostics Spectrometer, a solar observation instrument on the SOHO satellite
helium	Symbol:"He" Atomic Number:"2" Atomic Mass: 4.00amu
line of apsides	The apsides are the points of an orbit of one body around another is either greatest or least
birkhoff's theorem	(a) Every centrally symmetric geometry which is free of mass-energy is static and identical up to a coordinate transformation with the geometry defined by the Schwarzschild metric
biosphere	The layer of soil, water, and air surrounding the Earth in which living organisms thrive.
compact infrared sources	Strong compact infrared sources embedded in nebulosity
element	A substance that is made up of atoms with the same number of protons in their nuclei
semi-minor axis	Half of the shortest diameter of an ellipse.
html	Hyper-Text Mark-up language.
sunspot	Areas of the Sun's surface that are cooler than surrounding areas
zenith	the point on the celestial sphere directly overhead
loop nebula	see 30 Doradus [H76]
heat	COLD ADVECTION
eccentricity	The distance between the foci of an ellipse divided by the major axis.
galactic halo	Any of the material, in a roughly spherical distribution, surrounding a galaxy.
eclipse year	The interval of time (346.62 days) between two successive passages of the Sun through the same node of the Moon's orbit
carbonate pump	The carbonate pump is a net downward flux of carbon associated with the transport of calcium carbonate from the surface layer, where it is produced because of biological activity, to the deeper layers where it could be dissolved
rtu	Remote Terminal Unit, a semi-intelligent device which is linked to the PMC by the OBDH bus and which proveides control and monitoring functions for relatively simple equipment such as power distribution units.
brilliancy	For Mercury and Venus the quantity ks2 / r2, where k = 0.5(1 + cos i), i is the phase angle, s is the apparent semidiameter, and r is the heliocentric distance
intelligence	Defined in SETI as the ability and willingness to transmit electromagnetic signals across interstellar space
el niã±o	HUMIDITY
meteor shower	the appearance of many meteors in a short space of time, all radiating from a common point
wormhole	an object with two mouths in different parts of our universe connected by a tunnel that allows two-way traffic; they may be safe shortcuts through space
optical matching	The use of lenses or other optical devices to match the size of the image of the seeing disk, as it appears in the focal plane of the telescope, to the physical size of the CCD pixels
wien's law	A formula giving the wavelength W at which the maximum amount of radiation comes from a body of temperature T
iron meteorite	Meteorite composed of a nearly pure nickel-iron alloy.
feminine signs	Earth and water signs
partial pressure	Partial pressure is the pressure of one gas in a system of two or more nonreacting gases.
galaxy group	Between a few a few dozen galaxies held in on region of space by gravity.
su	Symmetrical Unitary of Order 5: The simplest type of grand unified theory, proposed in the 1970s
sculptor	1
local mean time	The actual time in a given location based upon the Sun's position at the Midheaven (noon) of the place
celestial equator	the Earth's equator projected onto the sky
anaxagoras	Greek 500-428 B.C., studied in Egypt and thought the Sun went under a flat Earth each night.
transition element	Transition elements (also known as transition metals) are found in the middle section of the periodic table
etalon	Essentially an optical filter that operates by multiple-beam interference of light reflected and transmitted by a pair of parallel flat reflecting plates
constellation	A group of stars that make a shape (they look like connect-the-dots) - usually named after mythological characters, people, animals and things.
gf-values	Weighted oscillator strengths
circumpolar	A celestial object such as a star, constellation, or deep-sky object that is so close to the celestial pole that it never rises or sets from an observers location.
mean molecular weight	Total atomic (or molecular) weight divided by the total number of particles
bose-einstein nuclei	Nuclei of even A-number (i.e., those with integral spin) (cf
scorpius ob1	An extremely young association of OB stars in Scorpius about 2 kpc distant
climate sensitivity	See equilibrium climate sensitivity.
campanus	Thirteenth century astrologer and mathematician who devised the house system that bears his name, which divides the prime vertical into equal 30° arcs.
foehn wind	SARGASSO SEA
grotrian diagram	Energy-level diagram
indeterminacy principle	Quantum precept indicating that the position and trajectory of a particle cannot both be known with perfect exactitude
mundane aspects	Aspects by house rather than by degree
vacuum fluctuation	An unpredictable event occurring in the vacuum as a result of the inherently probabilistic nature of quantum theory
cryosphere	The cryosphere is the portion of the Earth's surface where water is in solid form (sea ice, lake and river ice, snow cover, glaciers, ice caps and ice sheets)
aphelion	The point in an orbit where a planet is at its furthest distance from the Sun
government service jack	Generally, but not exclusively, limited to the UK and former British colonies, and flown at the bow by civilian-manned Government vessels – but see ‘colonial jack 1)’ with its following note (also ‘government ensign’ under ‘ensign’ and the notes below).
yachting crown	In UK usage, a crown formed from various modern yachting sails placed upon a circle or fillet that appears on the duty ensign and burgee of the British Yachting Association and is (as far as is known) unique to them – the RYA crown – but see note below (also ‘fillet 3)' and ‘naval crown').
timing waveform	A diagram showing the time sequence and voltage levels of a stream of pulses required, for instance, to perform charge-coupling in a CCD
cooper pair	a complex of two fermions in a degenerate Fermi system, which resembles a diatomic molecule
cosmic string	a tubelike configuration of energy that is believed to have existed in the early universe
veteran’s flag	The flag of an organization representing the veterans of a particular, service, war, campaign, or unit
vallis	a sinuous valley.
bulb	This is a setting usually seen on old SLR cameras (and now seen in a different guise in the manual mode on some DSLRs), which allows the shutter of the camera to be left open for an extended period of time
cavus	a hollow, irregular depression
su	mathematical structure known as a `group' that describes operations on N objects
z	Zetta, a multiplier, x1021 from the last letter of the Latin alphabet
sundial	Ancient instrument used to tell time.
symmetry breaking	(a) A reduction in the amount of symmetry a system appears to have, usually associated with a phase transition
half-life	In any phenomenon, the time during which the main variable changes by half its original value; often used loosely to indicate the characteristic time scale of a phenomenon
-particle nuclei	Nuclei formed by the -process
lhe	The symbol for Liquid Helium
einstein universe	A world model of a static Universe with a positive cosmological constant, whose radius of curvature is constant and independent of time
induced emission	See stimulated emission
azimuth	Azimuth is a horizontal measurement used to locate the position of an object in the sky
jack staff	The short staff in the bows of a ship upon which the ‘jack’ is hoisted (see also ‘ensign staff’, ‘jack’ and ‘staff 1)’).
cfht	Canada France Hawaii Telescope
rr lyr	(a) Periodic variables with periods less than one day, and of spectral types A to early F
spitzer-oort hypothesis	A hypothesis which explains the mass motion of the interstellar gas in terms of the gas pressure gradients existing between H I and H II regions
geology	The study of the history, origin, and structure of Earth. This term has been extended to include other planets.
anisotropic superfluid	A system of fermions in which Cooper pairs form in a state of finite relative orbital motion and possibly finite total spin
larmes	See ‘gouttes’.
dbu	Digital Bus Unit, which provides the electrical interface between the signals on the OBDH bus and terminal equipment such as ICU's.
hadron	(a) The generic name for any particle which experiences the strong nuclear force
einsteinium	Symbol:"Es" Atomic Number:"99" Atomic Mass: (252)amu
long wave radiation	another name for infra red radiation, or heat
microwave background anisotropy experiment	An experiment designed to measure the intensity of the cosmic microwave background radiation in different directions
charge bleeding	The overflow of charge up and down a column in a CCD when the pixel or storage well becomes saturated with photoelectrons
curie	(a) Unit of radioactivity
early-type spiral	In Hubble's classification, a spiral with a large nuclear bulge and closely coiled arms
absorption coefficient	Fraction of the incident radiation absorbed at a certain wavelength per unit thickness of the absorber
calendar	a system of division of time into different periods mostly according to astronomical events, but also sometimes arbitrarily
oceanic mixed layer	The oceanic mixed layer is the upper part of the ocean which is in direct contact with the surface
anisotropy	(a) A medium is anisotropic if a certain physical quantity differs in value in
speed of light	light travels at 186,000 miles per second, or 299,792,458 meters per second
concentration	Concentration is the amount of one substance in a system relative to the amount of other substances
exoergic process	A process in which energy is liberated
edge waves	An ocean wave travelling parallel to the coast, with crests normal to the coastline
pallia	Pre-heraldic banners of varying design presented by the Pope to indicate his approval and/or support for a person or cause (see also ‘Bayeux tapestry', ‘gonfanon’, ‘pall’ and and ‘pre-heraldic’).
prismatic habit	A shape of a large group of crystals that is very geometric and orderly
state space	the mathematical space whose points represent the states of a physical system
retest!	An exclamation in jest usually interjected when a Mensan does or says something out of keeping with their normal high intelligence.
differences	Differences are the adjustments which are applied to the predictions at a reference port or reference current station to obtain predictions at a secondary port or secondary current station.
iris	An arrangement able to vary the amount of light that enters an optical instrument
adsorption	A process in which a layer of atoms or molecules of one substance forms on the surface of a solid or liquid
scope-cm	Sustained and Coordinated Processing of Environmental Satellite Data for Climate Monitoring
bandera de ceremonia	See ‘indoor flag’.
equilibrium	A condition of balance between the forces operating on or within a physical system, so that no accelerated motions exist among the parts of a system
capture	The absorption of one particle by another
elliptical	In the shape of an ellipse
planitia	low plain.
toy theory	A theory which is known to be too simple to describe reality, but which is nonetheless useful for theorists to study because it incorporates some important features of reality
focal plane scale	The relationship between angles on the sky, in seconds of arc, and millimeters of size at the focus of the telescope; i.e
big-bang nucleosynthesis	The process, which took place between one second and 3-4 minutes after the beginning, in which the protons and neutrons of the primordial soup condensed to form the lightest atomic nuclei: Deuterium, Helium-3, Helium-4, and Lithium-7
mountain breeze	VAPOR PRESSURE
hypothesis	A proposed explanation of an observed phenomenon or a proposal that a certain observable phenomenon occurs.
event horizon	the "edge" of a black hole: and imaginary surface where the escape velocity reaches the speed of light
prime meridian	The great circle that passes through Earth's poles and Greenwich, England (0° longitude), from which longitude is measured east and west
metar	DROPSONDE
stratosphere	The stratosphere is the layer of the atmosphere located above the tropopause, at an altitude between roughly 10 and 50 km
celestial poles	The projection of the Earth's poles onto the celestial sphere.
flat field	Or flat-fielding
arrow of time	The sense that time moves in only one direction
jagiellonian cross	See ‘cross of Lorraine’ (also ‘jagiellonian’ above).
tidal constants	Tidal relations that remain essentially constant for any particular locality
muon collider	A type of particle accelerator capable of smashing particles called muons and anti-muons together to study high-energy collisions.
mixed	A type of tide in which a diurnal wave produces large inequalities in heights and / or duration's of successive high and low waters
octahedral crystal	This is a crystal that has eight sides
wavelength	The distance that a wave from a single oscillation of electromagnetic radiation will propagate during the time required for one oscillation .
winds	CUMULONIMBUS MAMMATUS
equator	A parallel therefore is a location of equal latitude
halo stars	Stars that have high spatial velocity and low metallicity
equator	The line where a plane that is perpendicular to a bodies axis of rotation, and passes through its centre, crosses the surface of the body.
tdcf	Table Driven Code Form
absorptance	Symbol: The ratio of the radiant or luminous flux absorbed by a body or material to the incident flux
h- ion	An H ion with an extra electron in its shell
mph	Main Product Header, the main description record at the start of every product, it follows a generic format.
upright pile	See ‘pile 1)’.
lisa	Large Interferometric Space Antenna
gravity	The force that pulls things toward each other
salts	Ionic compounds that can be formed by replacing one or more of the hydrogen ions of an acid with another positive ion.
electron-volts ev	measure of energy based on accelerating an electron through one volt
spin network	A term used by Roger Penrose to denote collections or networks of quantum mechanical spinors
beehive cluster	See Praesepe
poles	CENTRIPETAL FORCE
solstice	Literally "sun still"
clouds	CRYSTALLIZATION
etalon	An etalon is an optical device used to filter specific wavelengths of radiation by reflecting it many times between two parallel glass panels.
galaxy	Granulation A pattern of small cells that can be seen on the surface of the Sun
y shape	See ‘pall’.
limb	The edge of any object in Outer Space
sensor noise	This is noise generated by a digital camera's sensor
minimum	MEAN SEA LEVEL
fesswise	See ‘in fess’.
climate system	The climate system consists of five major components: the atmosphere, the hydrosphere, the cryosphere, the land surface and the biosphere
stellar luminosity	the intrinsic brightness of a star relative to the Sun; for example, a star with a stellar luminosity of 25*L(sol) is 25 times brighter than the Sun
sequencer	That part of an electronic system responsible for the accurate phasing of time-critical events such as CCD clocking and readout
collapse of the wavefunction	In the Copenhagen interpretation of quantum mechanics, the result of an act of measurement, in which the potentialities inherent in the quantum wavefunction take on a specific value, namely, that which is measured
meteor shower	An annual display of several to hundreds of meteors visible every hour
trail	The short-term luminous glow left in the path of a meteor, a.k.a
center of curvature	Each surface of a simple curved lens or mirror is part of a sphere
white light	Visible radiation that gives a sensation of whiteness
silicate	a rock or mineral whose structure is dominated by bonds of silicon and oxygen atoms (ie
transient lunar phenomena	These are colour changes and brightenings on the Moon's surface, reported by some lunar observers
season	NITROGEN (N2)
logistic equation	models the growth of a population as a competition between self-reproduction on the one side and inhibition arising from density-dependent effects on the other side
gauge field	An energy field that permits a gauge symmetry
altitude	STRATOSPHERE
water signs	Cancer, Scorpio and Pisces, members of the water triplicity that symbolize receptivity, sensitivity and emotional depth.
secular	In astronomy, gradual, taking aeons to accomplish
natural chart	A chart with 0° Aries on the cusp of the first house that shows the natural horoscope position of signs
ap stars	Peculiar A-type stars ("magnetic" A stars) that show abnormally strong lines, sometimes of varying intensity, of certain ionized metals
energy band	a continuous range of energies in a solid in which there are possible states for the electrons
singularity	the center of a black hole, where the curvature of spacetime is maximal
current	Generally, a horizontal movement of water
radial pulsation	Periodic expansion and contraction of a star that may be merely an optical effect of recession
sum-over-paths	Formulation of quantum mechanics in which particles are envisioned to travel from one point to another along all possible paths between them
moment of inertia	The product of the mass of a body and the square of its radius of gyration
hagedorn equation of state	An equation of state for extremely degenerate matter (density greater than about 1015 g cm-3)
sub-atomic	Of a scale smaller than that of an atom
segmented mirrors	A large mirror construction technique in which many smaller elements are built and then actively controlled to conform to the shape of the required large mirror
proper motion	Odin was the king of the gods...
natural astrology	See Meteorological astrology.
obliquity	The angle between a body's equatorial plane and orbital plane.
quindecile	A minor easy aspect, the fifteenth harmonic, 24°.
galactic latitude	The angle between the line of sight to a star and the Galactic plane
u geminorum star	A type of dwarf nova (q.v.)
iodine	Symbol:"I" Atomic Number:"53" Atomic Mass: 126.90amu
solar constant	Total solar power received by a surface one meter square, perpendicular to the solar radiation, at a distance of 1 AU (1366.1 W m-2).
stratification	The stratification is a measure of the vertical density gradient
electroweak force	(a) The combination of the electromagnetic force and the weak nuclear force which takes place at high energy
mixmaster model	(a) A non-Friedmannian cosmological model that begins with a highly anisotropic infant Universe and shows how anisotropies are reduced in time
limestone	Limestone is a sedimentary rock mainly composed of calcite
radiometric dating	Determination of the age of objects - e.g., earth and moon rocks - by means of the half-life of the unstable elements they contain
parallax	The apparent shift in the position of a celestial object when viewed from different positions.
angles	The Ascendant, Descendant, Midheaven and Imum Coeli; the four cardinal points in a horoscope.
conservative field	A field of force such that the work done on or by a body that is displaced in the field is independent of the path
old	a planetary surface that has been modified little since its formation typically featuring large numbers of impact craters; (compare to young).
isotropic	(a) Having equal and uniform properties at all points and in all directions
obscurations	SLEET
c class	Common asteroid class in the outer part of the Main Belt
absorption spectra	Also called dark line spectra, these arise when photons of specific frequency are absorbed by cooler gas, leaving a darker line on a background continuum region
stationary limit	In the Kerr solution to Einstein's equations, a surface on which a particle would have to travel at the local light velocity in order to appear stationary to an observer at infinity, and just inside which no particle can remain stationary as viewed from infinity
ablation	Erosion of an object (generally a meteorite) by the friction generated when it passes through the Earth's atmosphere
ellipse	A flattened circle, or oval.
tube rings	Rings that attach to a telescope's mounting plate (see dovetail plate) and hold the tube assembly in place.
flash flood	GUST
inflation	(a) The idea that, when it was a fraction of a second old, the universe expanded dramatically
ecliptic	The plane in which Earth orbits the sun.
ephemeris	A table of data arranged by date
absolute zero	The temperature at which the motion of all atoms and molecules stops and no heat is given off
vla	Very Large Array A network of 27 radio telescopes in New Mexico, USA
percentage composition	This composition measurement reflects the percentage of total mass for a specific element
convection	fluid circulation driven by large temperature gradients; the transfer of heat by this automatic circulation
co2	see Carbon Dioxide
earth	receives 12 hours of daylight and 12 hours of darkness.
geographic pole	Intersection between the rotation axis of any heavenly body and its surface.
chromospheric network	A large-scale cellular pattern along the boundaries of which lie bright and dark mottles seen in H and other regions
sensible heat	The sensible heat is the energy that can be transferred in the form of thermal energy or heat
infrared radiation	A bolometer works by heating up as it absorbs the radiation that reaches it
boron	Symbol:"B" Atomic Number:"5" Atomic Mass: 10.81amu
accidental ascendant	From Evangeline Adams' horary technique in which an Ascendant is determined according to the time and date of the questions, and the querent's natal horoscope is rotated according to this new or accidental Ascendant in order to make horary deductions from the natal chart.
pan-african colours	The green, yellow and red of the Ethiopian flag, adopted by a number of newly independent countries in Africa from 1956 onwards – and sometimes called the Rastafarian or Rasta colours - but see ‘Garvey colours’ and ‘Rastafarian colours’ (also (see also ‘core flag’, ‘difference’, 'flag family', ‘pan-Arab colours’ below and ‘pan-Slavic colours’).
electron volt	(a) Unit of energy
corundum	Al oxide, Al2O3, found in CAIs.
horizontal parallax	The difference between the topocentric and geocentric positions of an object, when the object is on the astronomical horizon
differentiation	Gravitational seperation or segregation of materials of different density into layers in the interior of a planet or satellite.
era	A system of chronological notation reckoned from a given date
m-theory	Theory emerging from the second superstring revolution that unites the previous five superstring theories within a single overarching framework
earth	is much greater than that between a person and the
star streaming	A phenomenon that arises because the mean random speeds of the stars are different in different directions
peb	Payload Equipment Bay, part of the Payload Module of the Polar Platform.
luminosity	A measure of the rate at which a star releases energy.
vertical triband	See ‘triband 1)’ and ‘triband 2)’.
orbit	The path of one object around another more massive object, defined by gravitational forces between the two objects.
doppler radar	MESOHIGH
m&ms	married Mensans
rayleigh scattering	Selective scattering (i.e., preferential scattering of shorter wavelengths) of light by very small particles suspended in the Earth's atmosphere, or by molecules of the air itself
o)	O-type stars in which NIII is present in emission and He is strong in absorption
wanderfahne	See ‘touring flag’).
absorption spectrum	Dark lines superposed on a continuous spectrum, caused by the absorption of light passing through a gas of lower temperature than the continuum light source
bottom-up structure formation	The idea that small structures, perhaps galaxies or even smaller substructures, form first in the universe, followed later by larger structures
trajectory	The path of a projectile or other moving body through space.
lennard-jones potential	An approximation of the interaction between two atoms or molecules
psychrometer	WHIRLWIND
magnetosphere	the are around a planet in which its magnetic field is dominant
cosmological model	The result of the theoretical calculation of an expansion curve obtained, for the case of relativistic cosmological models, from solutions to Einstein's field equations
complex number astrophysics	The basis of twistor theory
terra	extensive land mass.
einstein equations	The equations of Einstein's theory of gravity, called general relativity
meteorite	(a) Object that enters the Earth's atmosphere and is too large to be totally destroyed by friction before it hits the surface
base	A substance that may have a bitter taste, feels soapy, turns litmus blue, and can react with an acid to form salt
amc	American Mensa Committee; the ruling body of American Mensa
chromium	Symbol:"Cr" Atomic Number:"24" Atomic Mass: 52.00amu
sidereal period	Odin was the king of the gods...
gallium	Symbol:"Ga" Atomic Number:"31" Atomic Mass: 69.72amu
combination variable	see Symbiotic Star
precision	A measure of how finely a quantity can be specified, in terms of the number of significant figures in the measurement
association	A sparsely populated grouping (mass range 102-103 M) of very young, massive stars lying along a spiral arm of the Milky Way, whose spectral types or motions in the sky indicate a common origin
cantoned cross	See ‘cross cantonée’ in ‘appendix VIII’.
ellipse	A closed plane curve generated in such a way that the sums of its distances from the two fixed points (the foci) is constant.
metar	FUSION
cosmobiology	an astrological system developed by Reinhold Ebertin (Germany, twentieth century) that emphasized midpoints and the following hard aspects: semi-square, square, sesquiquadrate and opposition
pi	Principal Investigator, scientist in charge of an experiment.
exothermic	Process that gives off heat to the environment.
coulomb collision	The collision between two charged particles
light-year	The distance that light can travel in one year
anaerobe	An organism that does not depend on free oxygen for its metabolism.
corona	the outermost layer of the solar atmosphere
resonance	a state in which one orbiting object is subject to periodic gravitational perturbations by another
binaries	Albireo in Cygnus is an easy example to see and the two stars are different colours
meinel bands	Molecular bands of the N2+ radical near 8000 Å
magnitude	The measure of apparent brightness of a celestial object.
degree of arc	One degree of arc is 1/360 of a full circle
promethium	Symbol:"Pm" Atomic Number:"61" Atomic Mass: (145)amu
weak interaction	(a) One of the fundamental forces of nature
parallax	the difference in apparent direction of an object as seen from two different vantage points
orbit	The bursts may last from as little as a hundredth of a second up to 90 minutes
iberian cross	See ‘cross of calatrava’.
schuster mechanism	A scattering mechanism in the continuum, which under certain conditions can yield emission lines in the spectrum even under the assumption of LTE
semi-major axis	Half of the longest diameter of an ellipse.
summer solstice	The moment when the Sun reaches its greatest distance north of the celestial equator, on or about June 21
spectral bandwidth	The wavelength, or frequency range over which photons are detected at any one time; some detectors can operate in one or more bands placed within a broader range of spectral response.
vanadium	Symbol:"V" Atomic Number:"23" Atomic Mass: 50.94amu
rocket	A device propelled by ejection of matter, especially by the high velocity ejection of the gaseous combustion products produced by internal ignition of solid or liquid fuels.
elliptical galaxy	A type of galaxy which is oval in shape but has no apparent structure which contains old stars with little interstellar matter.
caldera	crater formed by an explosion or collapse of a volcanic vent.
fission	A nuclear process that releases energy when heavyweight atomic nuclei break down into lighter nuclei
skew t-log p diagram	VERTICAL VISIBILITY
tropic of cancer	The line of latitude on the Earth’s surface that is 23 1/2 degrees north of the Equator
inelastic collision	A reaction involving a change in the kinetic energy of the system, as in ionization, excitation, or capture; or a process which changes the energy level of the system
orbit	the path followed by an object in space as it moves moves around another object
decorated	See ‘garnished’.
tidal difference	Difference in time or height of a high or low water at a subordinate station and at a reference station for which predictions are given in the tide tables
honeycomb mirrors	A construction method for a large mirror in which the back is hollowed-out to leave a ribbed structure that resembles a honeycomb
gyrosynchrotron radiation	Radiation emitted by mildly relativistic electrons
catalyst	Chemicals that are not consumed in a reaction, but, which speed up the reaction rate
abased	(adv) A heraldic term for when the main ordinary on a shield, banner of arms or flag is placed in a lower position than is usual - lowered (see also ‘banner of arms', ‘enhanced' and ‘ordinary').
telescope	An instrument that uses lenses and sometimes mirrors to collect large amounts of light from distant objects and enable direct observation and photography
magnesium	Symbol:"Mg" Atomic Number:"12" Atomic Mass: 24.31amu
palus	A Latin term meaning 'swamp' that is used to describe topographical features on the moon which resemble dark plains or swamps
luminous	Intrinsically bright, as opposed to being just apparently bright
celestial meridian	The great circle on the celestial sphere which passes through the celestial poles and the zenith of the observer
badge banner	The term for a small square flag showing a person’s badge, probably against livery colours, and particularly (but not exclusively) for use at that person’s funeral – a practice now largely obsolete (see also badge in heraldry ‘bannerole’, ‘great banner’, ‘grumphion’ ‘livery banner’ and 'livery colours').
invisible astronomy	The study of celestial objects by observing their radiation at wavelengths other than those of visible light
snr	(a) Supernova Remnant [LLM96] (b) Signal-to-Noise Ratio
nationally-cantoned flag	See ‘canton flag’.
khanda	A blue emblem, usually on a triangular pennant with saffron field and symbolic of the Sikh religion (see also ‘pennant 2’ and ‘religious flag’).
cardinal signs	Aries, Cancer, Libra and Capricorn
pdhs	Payload Data Segment, comprises all those elements which are related to payload data acquisition, processing, archiving and those concerning the user interfaces and services.
charf	A permanent blemish on an image-tube phosphor
electromagnetic field	Force field of the electromagnetic force, consisting of electric and magnetic lines of force at each point in space
rotary current	A tidal current that flows continually, with the direction of flow changing through 360° during a tidal cycle
icarus	Asteroid No
magnetopause current	Current created by the separation of solar wind charges on the magnetopause.
kirkwood gaps	Regions in the asteroid belt where almost no asteroids can be found
palus	literally "swamp"; really a small plain
gista	Geo-Informatics and Space Technology Development Agency - GISTA website GISTDA is public organisation in Thailand that develops and applies Earth observation satellite technology and Geo-Informatics for the benefit of Thailand as a whole.
stimulated emission	(a) Radiation emitted by a body, such as an atom, when it is bombarded by radiation
ecliptic	The imaginary line on which the Sun travels through our sky.
rti	Rise Time Invariance.
mohs scale	This is a scale that measures the hardness of rocks and minerals
chromatic aberration	an optical lens defect causing color fringes, because the lens material brings different colors of light to focus at different points.
quantum electrodynamics	QED (a)The quantum field theory describing the interactions between electrically charged particles through the electro-magnetic field (whose quantum is the photon)
iridium	Symbol:"Ir" Atomic Number:"77" Atomic Mass: 192.22amu
cygnus loop	A gaseous nebula (a supernova remnant) (NG6 6992, Cyg X-5), consisting of a large loop of gas ejected from a star about 20,000 years ago
convection zone	The region of the interior of the Sun which lies just below the surface
einstein equivalence principle	Foundation for curvcd space-time, it states that bodies fall with the same acceleration and that physics in freely falling reference frames is independent of the velocity and location of the frames
mean solar day	The mean length of time (24h00m00s) between two successive culminations of the Sun (i.e., the mean period from apparent noon to apparent noon)
closed system	A set of one or more objects that may interact with each other, but do not interact with the world outside the system
b	Spectral type for blue stars, such as Rigel, Spica, and Regulus
name pennant	The term for a flag or pennant that bears the name of a ship or possibly a shipping company or an institution – an onomast.
barium	Symbol:"Ba" Atomic Number:"56" Atomic Mass: 137.33amu
banner of the realm	A translation of the Dutch “rijksvaandel” and proposed translation of the Norwegian term “riksbanner” - a royal banner - but see ‘coronation flags’.
jpss	Joint Polar Satellite System
bootstrapping	A hypothesis about the nature of the elementary particles derived from S-matrix theory
active optics	Controlling the shape of a telescope mirror at a relatively slow rate
giant branch	A conspicuous sequence of red stars with large radii in the H-R diagram of a typical globular cluster that extends from the main-sequence turnoff point upward and redward to the red-giant tip
zeolite	An absorbent material (in the form of small pellets) used in low-temperature cryostats to trap gases released gradually after active pumping has ceased
decimal system	The system of counting and arithmetic based on factors of ten (the binary systemis based on factors of two).
stefan-boltzmann constant	(a) : The constant of proportionality relating the luminosity of a star to its absolute temperature: = 5.67 × 10-5 ergs cm-2 (deg-K)-4 s-1
magnetosphere	the area around a planet most affected by its magnetic field
pageant standard	A term, now obsolete, for the Scottish heraldic standard as carried on ceremonial occasions; and there are indications that it was the middle of three sizes (see also ‘battle standard’, ‘pinsel', ‘standard 4)’, and ‘great standard’).
zenith	The point on the celestial sphere that is directly above an observer.
house	One of the twelve divisions of the Celestial Equator
intercombination lines	Spectral lines emitted in transitions between two levels with different values of S
h-alpha light	Atoms emit radiation at certain wavelengths based on how the electrons move between certain fixed energies
offset dish antenna	The offset dish antenna has the LNC located to the side of the dish
configuration	(a) The arrangement of electrons in shells around the nucleus of an atom
anomalous zeeman effect	Splitting of spectral lines into several components, in contrast to the normal Zeeman effect which results in only two distinct components
helium variable stars	Bp stars in which the strength of the helium lines varies periodically
ph	A scale from 1 - 14 that measures how acidic or basic (alkaline) a substance is.
atomic weight	The mean atomic mass of a particular element in atomic mass units
easter	main feast of Christian churches
transputer	A compact computer chip with a special design for linking to other transputers to make the program run faster
secular year	a year whose number leaves no remainder when divided by 100
tachyon	(a) A hypothetical subatomic particle that can travel faster than the speed of light
secondary control tide station	A tide station at which continuous observations have been made over a minimum period of time
m numbers	Refer to the Messier Catalogue
vertical bicolour	See ‘bicolour 1)’ (also ‘bicolour 2)’).
aperture	the diameter of an opening through which light passes in an optical instrument
auto-catalysis	the ability of certain chemicals to enhance by their presence the rate of their own production in a sequence of chemical reactions
eccentricity	A value between zero and one which represents the shape of an ellipse or an orbit
scintillation counter	A device used with a photomultiplier tube to detect or count charged particles or gamma rays
gev	(a) One thousand million electron-volts
carter's theorem	Sequences of axisymmetric metrics external to black holes must be disjoint, i.e., have no members in common
lithosphere	The lithosphere is the outermost part of the solid Earth
indium	Symbol:"In" Atomic Number:"49" Atomic Mass: 114.82amu
cmos	Complementary metal oxide semiconductor
principal vertical circle	The vertical circle through the east and west points of the horizon, and hence perpendicular to the principal vertical circle, is called the prime vertical circle, or simply the prime vertical.
stokes	1 St = 1 cm2 s-1
second law of thermodynamics	(a) A physical law formulated in the nineteenth century and stating that any isolated system becomes more disordered in time
apochromatic lens	A lens designed to correct for chromatic aberration at three different wavelengths
radiative braking	The slowing down of rotation of a star due to radiation
midas	Munich Image Data Analysis System -- A suite of programs and a software environment developed at the European Southern Observatory for astronomy applications
celestial sphere	An imaginary sphere encompassing the Earth that represents the sky
bamberga	Asteroid 324 (a = 2.80 AU, e = 0.36, i = 11°.2)
implicate order	A term coined by the physicist David Bohm to describe the sort of enfolded order that is characteristic of quantum theory
mach number	(a) The ratio of the speed of a moving object (e.g
magnetic north	Earth's magnetic north and south poles are not located exactly at the rotational north and south poles
disk	The flattened structure of a circular collection of material, which often refers to the overall structure of a spiral galaxy
longitude	Angle between the reference meridian (at Greenwich, England) and a point on the surface of the Earth
gear wheel	See 'cog-wheel'.
aplanatic lens	A lens designed so as to minimize both its astigmatic and coma aberration
coma	(a) An aberration common in traditional reflecting telescopes, in which off-axis rays of light striking different parts of the objective do not focus in the same image plane
invariant	(a) Any physical property which does not change under the transformation from one frame of reference to another
ephemeris second	The length of a tropical second (1/31,556,925.97474 of the tropical year) on 1900 January 0.5 ephemeris time
latin cross	See ‘appendix VIII’.
surface gravity	g: Also called acceleration due to gravity
catoptric	Concerning reflections
flop transition	Evolution of the Calabi-Yau portion of space in which its fabric rips and repairs itself, yet with mild and acceptable physical consequences in the context of string theory
mt. wilson	The location, in California, of the 100-inch diameter telescope used by Edwin Hubble and others
rhodium	Symbol:"Rh" Atomic Number:"45" Atomic Mass: 102.91amu
ijrs	International Journal of Remote Sensing
fire alert flag	In largely US usage, a flag with a red field and inscriptions raised in conjunction with a wildfire danger warning by the Forestry Commissions of many states (see also ‘red flag 1)’).
schwarzschild solution	Solution to the equations of general relativity for a spherical distribution of matter; one implication of this solution is the possible existence of black holes
matter	In his famous equation E=mc2 Albert Einstein stated that mass (m) is equivalent to energy (E) - the two parameters are related via the speed of light (c).
laplacian determinism	Clockwork conception of the Universe in which complete knowledge of the state of the Universe at one moment completely determines its state at all future and past moments
astrology	a belief system which claims that the positions of celestial objects affect or control life on Earth
maia sequence	a hypothetical sequence of blue variable stars named for the B-type star Maia (20 tau) in the Pleiades
carbon	Symbol:"C" Atomic Number:"6" Atomic Mass: 12.01amu
jd	Julian Day -- A unit of time within the Julian Dating System where the number of ephemeris days that have elapsed since 12h ephemeris time on January 1, 4713 B.C
lorentz transformation	(a) The transformation which keeps the speed of light invariant between relativistic frames of reference
stefan-boltzmann law	A law giving the total energy E radiated from a surface of area A and temperature T per second: E= sigmaT^4 A
hyad	A single member of the Hyades
mass	A fundamental property of an object comprising a numerical measure of its inertia; the amount of matter in the object
minkowski space-time	space and time considered together, with special importance attached to the progress of a light flash, and to the light-cone and the `interval'
progression	A method of advancing the planets and points of a natal chart to a particular time after birth.
isospin	(a) A quantum number which arises from regarding different members of a charge multiplet (q.v.) as different states of a single particle
magnetic pole	either of two limited regions in a magnet at which the magnet's field is most intense.
b[e] stars	Be stars exhibiting forbidden lines in emission
azimuth and elevation	an angular coordinate system for locating positions in the sky
old	a planetary surface that has been modified little since its formation typically featuring large numbers of impact craters (compare young).
einsteinium	A radioactive transuranic element of the actinoid series, not found naturally on Earth
astronomical coordinates	The longitude and latitude of a point on the Earth relative to the geoid
spherical aberration	An effect caused by curved mirrors and lenses, in which light hitting the edge of the mirror is focussed at a slightly different point to that hitting the centre.
liquefaction	A process that increases the pressure on a gas until it becomes a liquid
radionuclides	Gamma rays are similar to X rays rays, but X rays generally have lower energy
after-image	An image seen after the eye's retina has been exposed for a time to an intense or stationary light source
earth	, we create electrical energy for our homes at power plants, we turn gasoline into energy to make our cars run, and we eat foods so that our bodies have energy to move
born-oppenheimer approximation	An approximation that treats the motion of an electron under the attraction of two free nuclei by regarding the nuclei (because of their greater mass and consequent smaller velocities) as fixed
bit	(a) In computer terminology, a shortened form for binary digit (0 or 1)
conjunction	A time when two or more bodies appear close together in the sky
observatory	A place or an instrument for observing objects and events in space
cosmic distance ladder	(a) The methods by which increasing distance is measured in the cosmos
heat	The energy of motion of particles in an object.
mercury	Symbol:"Hg" Atomic Number:"80" Atomic Mass: 200.59amu
crater	A bowl-shaped hole on the surface of a planetary object
sunspot	darker and slightly cooler region on the surface of the sun, created when powerful magnetic fields stop the circulation of gases.
t	Tera, a multiplier x1012, from the Greek teras (monster)
chemical lifetime	Length of time a chemical species can survive without reacting, photolyzing, dissociating, or otherwise changing into another chemical species
in abeyance	The term used when a flag or office is no longer in current use, but which may be re-introduced at some future date – with examples being the rank flag of Marshal of France (which office has no extant holder) and the broad pennant of a commodore first class (a rank in abeyance since 1958 – see the second note following ‘flag captain'; also ‘broad command pennant 2)’ and ‘rank flag 1)’).
period	The time taken for one orbit, or the time between repeated events.
altitude	The angular elevation of an object above the horizon.
klein-gordon equation	A fundamental equation of relativistic quantum field theory
rift valley	an elongated valley formed by the depression of a block of the planet's crust between two faults or groups of faults of approximately parallel strike.
universe	which tries to explain its origin, evolution and ultimate fate and thus forms the basis of modern cosmology
galley	1) Generically a ship whose motive power was principally provided by her oars (see also ‘galley ensign')
metal-rich stars	Stars having metal-to-hydrogen ratios greater than those of the Hyades
radiant	the point in the sky from which meteor showers appear to originate
barred irregular galaxy	This is an irregular galaxy which exhibits a bar structure.
upright pall	See ‘pall 1)’.
atmosphere	SHOWALTER STABILITY INDEX
intrinsic luminosity	The energy per second emitted by an astronomical object, analogous to the wattage of a light bulb
coulomb-born approximation	An approximation similar to the Born approximation (q.v.) except that Coulomb waves replace plane waves for the incident and scattered photons
zenith	The point in the sky directly above the observer
craterlet	A small crater ranging from a few millimetres across to a few metres.
radio window	The wavelength range between a few millimeters and about 20 meters within which Earth's atmosphere is transparent to radiation
arc spectra	The spectra of neutral atoms produced in a laboratory arc (cf
vector space	A set of elements (called Vectors) for which a binary operation of vector addition is defined, such that u1 + u2 is a vector if u1 and u2 are vectors: and a binary operation scalar multiplication is defined, such that cu is a vector if u is a vector and c is a scalar (a real number or a complex number, according to specification of the kind of vector space); and a standard collection of conditions governing these two operations is satisfied
sextant	Instrument employed to measure the elevation of astronomical objects above the horizon
centrifugal force	The outward-tending apparent force of a body revolving around another body.
azimuth	Hour Angle: The angle, measured westwards around the celestial equator, between the observer's meridian and the hour circle of an object.
sabian symbols	A system developed by Elsie Wheeler (psychically), Marc Edmund Jones and Dane Rudhyar that assigns an occult or esoteric meaning to each degree of the zodiac.
spin-flip collisions	Collisions between particles in which the direction of the spin angular momentum changes
greenhouse effect	Heating of an atmosphere by absorption of outgoing infrared radiation.
absorption lines	Dark lines in a spectrum, produced when light or other electromagnetic radiation coming from a distant source passes through a gas cloud or similar object closer to the observer
solute	A solute is the substance to be dissolved
prenatal epoch	The astrological moment of conception
local inertial frame	A coordinate system or frame of reference defined in the vicinity of the earth in which Newtons first law of motion is valid; that is, a nonrotating and nonaccelerating reference frame
oblique desension	The angular complement of oblique ascension; i.e., 180° minus the oblique ascension arc.
via combusta	Literally fiery way; refers to a section of fixed stars that falls between 15° Libra and 15° Scorpio
cygnus x-5	see Cygnus Loop
tornadoes	SEA BREEZE
razin effect	The strong suppression of low-frequency (synchrotron) radiation by electrons moving in a cool, collisionless plasma
g-factor	Ratio of a particle's magnetic moment to its spin angular momentum
phosphorus	Symbol:"P" Atomic Number:"15" Atomic Mass: 30.97amu
rydberg	A unit of energy (R = 3c / me4) equal to 13.5978 eV (the ionization potential of hydrogen).
retrograde	rotation or orbital motion in a clockwise direction when viewed from above the north pole of the primary (i.e
law	A theory of such wide and invariable application that its violation is thought to be impossible
electromagnetism	The science dealing with the physical relationship between electricity and magnetism
planitia	A low plain.
npoess	National Polar Operational Environmental Satellite System
absorption	The loss of photons as light passes through a medium
goos	Global Ocean Observation System
formic acid	H2C02 -- A simple organic acid, the first to be detected in interstellar space (in 1970 at 18.3 cm)
dragon's head	Refers to the Moon's north node
greenwich observatory	The Royal Greenwich Observatory is athe national astronomical observatory of England
crystalography	Science of determining the arrangement of atoms in solids; the scientific study of crystals
ozone layer	The ozone layer is a region of the stratosphere which contains most (about 90%) of the Earth's atmospheric ozone
high pressure system	CYCLONIC FLOW
candela	Symbol: cd The SI base unit of luminous intensity; the luminous intensity in a given direction of a source that emits monochromatic radiation of frequency 540 × 1012 hertz and that has radiant intensity in that direction of 1/683 watt per steradian
families	(a) Organization of matter particles into three groups, with each group being known as a family
hubble program	The research program carried out in the 1920s and 1930s by Edwin Hubble to measure the recessional speeds and distances of a large number of galaxies and to attempt to measure the deceleration parameter
altimeter setting	METEOROLOGY/METEOROLOGIST
conduction	Transfer of heat as a result of collisions between molecules; when one end of an object is heated, the molecules vibrate faster and their energy is transferred sequentially to their neighbors
deduction	A logical method for combining ideas, observations, measurements, or numbers
ecliptic	The ecliptic is the apparent path that the sun follows over the surface of the celestial sphere through the course of the year
heliocentric	A Heliocentric system is one in which a sun is at the center.
spectrograph	(a) A device, usually based on a finely etched grate that performs the function of a prism, for breaking up light into its constituent parts and making a photographic or electronic record of the resulting spectrum
mensa	mesa, flat-topped elevation.
mendelevium	A radioactive transuranic element of the actinoid series, not found naturally on Earth
vair	The heraldic term for a fur (reputedly that of a squirrel), which is usually (but not invariably) shown as a series of blue inverted shield or bell-like shapes on a white or silver field (see also ‘ermine’, ‘furs’ in ‘appendix III:’ and ‘potent’).
parallax	The apparent movement of an object across the sky when seen from two different points, which can then be used to calculate the distance to the object by triangulation.
hd number	The HD (Henry Draper) number is an identifying number assigned to the strs in the Henry Draper catalog
cid	Charge Injection Device
sunrise/sunset	The times at which the apparent upper limb of the Sun is on the astronomical horizon; i.e., when the true zenith distance, referred to the center of the Earth, of the central point of the disk is 90°50', based on adopted values of 34' for horizontal refraction and 16' for the Sun's semidiameter
sdo	Subdwarf O stars showing few very broad and shallow Balmer lines and a very strong He II 4686 line
vertex	The point found in the western section of a horoscope that indicates the intersection of the ecliptic and prime vertical, called the "third angle of a horoscope"
solstice	the time when the sun reaches its greatest northern or southern declination
local group	Most Mensans are assigned to one local group, based on geography
gravitational radius	The radius which an object should have in order that light emitted from its surface just ceases to escape from its surface
ecclesiastic banner	See ‘banner 3)’.
emission lines	Bright lines produced in a spectrum by a luminous source, such as a star or a bright nebula
pixel	One of the elements that makes up the array in a CCD camera.
parallel	Two lines running side by side at an equal distance apart
holmberg radius	The radius of an external galaxy at which the surface brightness is 26.6 mag arcsec-2
ronchi grating	A Ronchi grating is a special type of diffraction grating used in optical tests
aphelion	The point in an object's orbit when it is the furthest from the Sun.
rotation	turning around a center or an axis, or to turn in a circle.
spectral bandwidth	The total wavelength or frequency range over which photons can be detected with reasonable efficiency.
crest	The highest part of a wave, swell, ridge, etc...
culmination	The position of a heavenly body when at highest apparent altitude
variable star	a star whose apparent brightness changes over time; this change may regular or irregular
christoffel symbols	Mathematical quantities used in the mathematical formalism of general relativity, Einstein's theory of gravity
equinoxes	The two points in the celestial sphere where the celestial equator intersects the ecliptic; also, the times when the Sun crosses the equator at these points
sea breeze	LANDFALL
mis	Metal Insulator Semiconductor
metar	SNOW ROLLER
irregular galaxy	a galaxy with no spiral structure and no symmetric shape
lsb	Least Significant Bit see also DN [McL97]
aphelion	For an object orbiting the sun, the point (distance and time) where/when the object is furthest from the sun in its elliptical orbit.
kinematics	The branch of mechanics that studies bodies undergoing continuous change of position
secular parallax	A parallax based on Solar motion; i.e., the baseline is the distance the Sun moves in a given interval of time with respect to the Local Standard of Rest (4.09 AU per year)
esrc	Environmental Satellite Resource Center
meridian	Odin was the king of the gods...
north celestial pole	The North Celestial Pole is the center of the Polar Sky Chart, just as the Earth's North Pole is usually the center of maps of the Earth's Arctic regions
evidence	Scientific evidence consists of quantitative observations or experimental results that can be confirmed by other investigators.
lyot division	In Saturn's rings, the gap between rings B and C
earth	are examples of small circles.
cp violation	(a) A reaction between subatomic particles is said to be a "CP violating" reaction if the reaction produces a different result when the electrical charges of the particles are changed to their opposites and the mirror image of the particle trajectories is used
collider	A collider is made by accelerating beams of particles and causing them to collide
chemical decomposition	This is the molecular action of the larger process of decomposition
hydroponics	Hydroponics is a method of growing plants in water that contains dissolved nutrients (instead of in soi).
resolution	A measure of the amount of detail visible in an image
radiocarbon dating	Determination of the age of a substance containing radioactive carbon by means of its radioactive half-life
poles	Points at the intersection between the axis of rotation of a sphere and its surface
hour angle	The angle, measured westwards around the celestial equator, between the observer's meridian and the hour circle of an object.
matter era	The era following the radiation era
ingress signs	The equinoctial (Aries and Libra) and solsticial signs (Cancer and Capricorn), the cardinal signs that coincide with the beginning of the seasons each year
equinox	The equinoxes are the moments when the Sun is positioned directly over the Earth's equator and, by extension, the apparent position of the Sun at that moment
conformal geometry	Conformal geometry is related to the stretchings of space-time that preserve the light cone structure
sunspots	Cooler (and thus darker) regions on the sun where the magnetic field loops up and out of the solar surface.
cathode-ray tube	Basis of the TV tube and the oscilloscope
cumuonimbus	VISIBILITY
quadrature	a point in the orbit of a superior planet where it appears at right angles to the Sun as seem from Earth.
temperature	A measure of how hot or cold an object or substance is
back focal length	The distance between the last surface of a compound optical system and the focal plane of the system
band	See ‘stripe(s)’ and ‘Appendix VI’.
rayleigh number	(a) A non-dimensional parameter involving the coefficients of thermal conductivity and kinematic viscosity which determines when a fluid, under specified geometrical conditions, will become convectively unstable
mills cross	An antenna array consisting of two antennas oriented at right angles to each other
extended inflationary universe	A version of the inflationary Universe theory proposed in 1989 by Paul Steinhardt and Daile La
aml	An abbreviation for "American Mensa, Limited"
regiomontanus	The German astrologer (fifteenth century) who devised the house system that bears his name
instability	STAGNATION AREA
sunspot	A dark blemish on the surface of the Sun which is cooler than the surrounding regions
equatorial mount	The classic type of telescope mount with one axis parallel to the Earth's polar axis (i.e
eccentricity	A measure of how elliptical an orbit is
heavy-fermion systems	a class of recently discovered materials, usually rare-earth or actinide compounds, in which the `effective mass of the electrons appears to be hundreds or thousands of times the real electron mass
cygni	see Deneb
comet nucleus	The brightest star-like object near the center of a comet's head; the physical body (believed to be icy and a few kilometers across) within a comet.
retrograde	(a) In a backwards direction; in astronomy this means in a direction corresponding to east-to-west
conjunction	There are at least three definitions of conjunction
umbra	The name given to the shadow cast by a celestial object that entirely blocks out illumination.
reconnection	The rejoining of magnetic lines of force severed by the annihilation of the field across the neutral region
apparent magnitude	the magnitude or brightness of a star as seen from Earth; magnitudes measure brightness on a logarithmic scale where a difference of 5 magnitudes is a factor of 100 times in brightness; the difference in brightness 'x' between two stars of magnitudes 'a' and 'b' is: x = 2.512(a-b)
gram	A gram is metric unit of measure for mass
magnetohydrodynamics	MHD The study of how magnetic fields interact with conducting fluids (e.g
latitude	Circles in parallel planes to that of the equator defining north-south measurements, also called parallels.
s-process	The process by which elements heavier than copper are formed through a slow flux of neutrons
aurora	Colorful curtains of moving light in the night sky caused by charged particles from the Sun interacting with Earth's atmosphere near the North and South Poles.
garnished	The heraldic term used when a charge (such as a horn, helmet or mitre etc) is decorated or ornamented with details in another tincture – but see ‘adorned 2)’ (also ‘charge 1)’, ‘barbed’, ‘hafted’, ‘hilted’, ‘shafted’ and ‘tincture’)
atomic mass unit	(a) A unit of mass used for atoms and molecules, equal to 1/12 of the mass of an atom of carbon-12
aatsr	Advanced Along Track Scanning Radiometer
lead	Symbol:"Pb" Atomic Number:"82" Atomic Mass: 207.20amu
regio	region.
bromine	Symbol:"Br" Atomic Number:"35" Atomic Mass: 79.90amu
hrs	High-Resolution Spectrograph (Hubble)
yellow map tack	A yellow map tack was worn by Mensans in the early days as a sign of membership
prism	A piece of transparent material that separates the colours of sunlight into a rainbow or spectrum.
hydrogen bond	A chemical bond that has hydrogen covalently bonded to an electronegative atom
current sheath model	A sunspot model in which the cylinder of the magnetic field is assumed to be surrounded by a current sheath which contains all the gradients of the field
sulcus	subparallel furrows and ridges.
fermi statistics	the form of statistics applicable to fermions
plage	bright regions seen in the solar chromosphere.
synastry	The astrological technique of comparing natal horoscopes to gain insight into the strengths and weaknesses inherent in the relationship that exists between the individuals involved
compensation depth	In isostasy, the depth (level) at which the overlying mass is independent of location
sublimation	CUMULIFORM
parallel	Two lines are parallel if they remain at a constant distance away from each other along their lengths.
mem	Maximum Entropy Method: An image reconstruction methodology which defines a measure of information content and seeks to maximize it
composite particle theory	A class of elementary particle theories, according to which there are increasing numbers of elementary particle states of higher and higher mass
vallis	sinuous valley (plural: valles)
metar	SIBERIAN EXPRESS
ombudsman	The person who acts as a mediator to help settle complaints and ease unhappiness.
rotation	the spin on a body's axis
rubidium	Symbol:"Rb" Atomic Number:"37" Atomic Mass: 85.47amu
feedback	A feedback tends to amplify (positive feedback) or reduce (negative feedback) the response of a system to a perturbation through mechanisms internal to the system itself
pall flag	That flag which is used to cover a coffin prior to interment, or the deceased person when lying in state – a burial, interment or casket flag (see also ‘flag case 2)', ‘flagfolding', ‘funeral flag’ and ‘mourning flag’).
quintile	The fifth harmonic, 72°, a minor easy aspect.
spectrum	A range of frequencies or wavelengths.
ultraviolet	electromagnetic radiation at wavelengths shorter than the violet end of visible light
winds	MACROSCALE
kiloparsec	Distance measure
lorentz force equation	The equation relating the force on a charged particle to its motion in an electromagnetic field
seas	HYDROLOGY
crater	bowl-shaped depression formed by the impact of a meteoroid; depression around the orifice of a volcano.
ft	Fourier Transform [LLM96]
altitude	TROPOSPHERE
quincunx	A minor hard aspect, separating distance 150°, the fifth multiple of the twelfth harmonic (30°, semi-sextile)
conduction	One of three processes that transfers heat from hot to cold regions; occurs as fast-moving molecules in the hot region agitate adjacent molecules.
umbra	The area of total darkness in the shadow caused by an eclipse.
radiant	The radiant is the point in the sky where meteors (associated with a specific meteor shower) appear to come from
colloquium	A gathering for serious thought, not just for fun.
light cylinder	The cylinder whose radius is that at which the rotational velocity of a neutron star would equal the speed of light
tdi	Time Delay and Integration or drift-scan
balmer formula	A formula which represents the wavelengths of the various spectral series of hydrogen: - = R(m-2 - n-2)
li-rich stars	A subgroup of C stars, with a very strong LiI 6078 line
lbv	Luminous Blue Variables -- A variable-star designation for the high-luminosity early type objects
longitudinal wave	A wave vibrating along the direction of propagation - e.g., a sound wave
permafrost	Permanently frozen ground.
solstice	Odin was the king of the gods...
stony iron	A meteorite that contains regions resembling both a stone meteorite and an iron meteorite.
scott effect	A selection effect in the study of the magnitude-redshift relation in cosmology
irradiance	Symbol: E The rate of energy reaching unit area of a surface; i.e
hexagonal crystal	This crystal shape has six sides and no specific length
satellite	Any object that orbits another, larger object
impale by dimidiation	See ‘dimidiated’ and following note (also ‘impale 1)').
ragged cross	A traditional symbol of Burgundy and later Spain, and a cross (more accurately saltire) composed of diagonal bars with small projections – a cross raguly (See also ‘raguly' and ‘saltire').
true north	(see also: magnetic north) the direction, along the surface of the Earth, toward the point where Earth's imaginary axis of rotation intersects Earth's surface in the northern hemisphere.
equator	The great circle on the surface of a body formed by the intersection of the surface with the plane passing through the center of the body perpendicular to the axis of rotation
satellite	a small object revolving around a larger object
meridian	an imaginary line on the sky that runs due north and south and passes through your zenith
dds	Data Dissemination System
coulomb	(a) The SI unit of charge
apparent brightness	The brightness of an object as perceived by an observer at a specified location (but not measuring the object's intrinsic, or absolute, brightness).
absorption	(a) A process in which a gas is taken up by a liquid or solid, or in which a liquid is taken up by a solid
sea level pressure	ALTIMETER SETTING
altitude	The angular distance of a celestical object above the local horizon
radarsat	Radar satellite
zenith angle	an angular measurement from straight up (zenith) to a point in the sky
safety flag	1) In Japanese usage one of several green and white flags symbolizing safe conditions in various situations (see also ‘weather flag 2)'
oxygen	Silicates are found in nature as the mineral quartz in its various forms
greater benefic	A term reserved for the planet Jupiter which, according to ancient beliefs, was responsible for life's greatest blessings.
apex	The direction in the sky toward which the Sun appears to be moving relative to local stars; located in the constellation Hercules.
meteor	The path made when a small particle of interplanetary dust entering our atmsophere burns up.
trekkie	(also "Trekker") a devotee of the science fiction program Star Trek.
isas	Institute of Space and Astronautical Science, Japanese space and space weather agency (http://www.isas.ac.jp/e/)
hamburgian coronet	A specific form of the mural crown and related directly to the city of Hamburg, Germany – see ‘mural crown 1)'
lacus	lake.
absolute temperature	(a) Temperature measured on the Kelvin scale: 0 Kelvin = -273.15° Celsius
sidereal time	Sidereal time represents the RIGHT ASCENSION currently on the Celestial Meridian
houses	The celestial sphere as a 360 degree circle is divided into twelve sections called houses
chaotic dynamics	time-dependent aperiodic regime in which individual histories corresponding to initially close states tend subsequently to diverge exponentially
thermosphere	ISALLOBAR
easterlies	Easterlies are winds coming from the east that are typically found in the tropics
kernelled	See ‘embattled’.
stellar wind	a steady or unsteady outflow of material from the surface of a star
ecliptic	Plane in which the Earth orbits the Sun.
culmination	(a) The instant at which a celestial object crosses the meridian
ariel	Second satellite of Uranus about 1600 km in diameter, discovered by Lassell in 1851
subduction	the process of one lithospheric plate descending beneath another.
atomic time	Time based on the atomic second (see Second)
event horizon	(a) The "edge" of a black hole; the interface between four-dimensional space and a singularity
alt azimuth	Mount type
filet	The heraldic term for a narrow horizontal stripe that is of no specified width, but which is considered to be a diminutive of bar – see ‘bar 1)’ (also ‘appendix VI’ and ‘barrulet').
luminous flux	Symbol: v The rate of flow of energy of visible radiation
longitude	Distance in degrees, minutes and seconds of any place east or west of Greenwich, England
equation of time	(a) The difference between Apparent and Mean Solar Time
element	A chemical material with a specified number of protons in the nucleus of each atom
rawinsonde	RADIAL VELOCITY
transmittance	The ratio of the transmitted energy that a substance allows through to the energy incident upon it
sao	Smithsonian Astronomical Observatory [LLM96]
resolution	The amount of small detail visible in an image (usually telescopic); low resolution shows only large features, high resolution shows many small details
reference station	A place where tide or tidal current constants have been determined from observations, and which is used as a standard for the comparison of simultaneous observations at a subordinate station
hyperfine structure	Splitting of spectral lines due to the spin and consequent magnetic moment of an atomic nucleus
asteroseismology	The study of the internal structure of stars by analysis of the way they pulsate.
radial velocity	(a) Velocity along the line of sight toward (-) or away from (+) the observer
light	A kind of energy, also called electromagnetic energy
mottle	An alternative word for spicule
solar flare	A violent eruption of gases into the solar atmosphere from the photosphere.
wind speeds	ISOTHERM
tsunami	A long-period sea wave produced by a submarine earthquake or volcanic eruption
hd	Henry Draper Catalogue, which lists over 200,000 stars
reciprocity failure	The non-linear behavior of a photographic emulsion in which an increase in exposure time does not correspond to an increase in sensitivity by the same factor
lagrangian point	A point of balance for a very small body relative to two larger bodies
latitude	The anglular distance north or south an object is as measured from the equator.
line width	The width of a spectral line in wavelength terms
prime feed focus dish	This is a large parabolic dish, with a diameter over 1.4 meters, with the LNC mounted centrally in the dish facing outward
canonical	The Canonical Approach to dynamics refers to the scheme in which the basic constituent is a space of states and the evolution of the system is described by a curve in this space parametrized by time
heavy snows	WATER
ccd	Charge Coupled Device, an integrating optical detector in the near infrared, visible and ultraviolet region
semi-convection	The partial convective mixing that takes place in a convectively unstable region where stability can be attained by the results of the mixing before the region is completely mixed
stomata	A stoma is a pore, found for instance in leaves, that is used by plants for gas exchanges with the atmosphere
charge carrier	Particle or feature having electric charge that can move freely through a material
equilibrium climate sensitivity	The equilibrium climate sensitivity is generally defined as the change in the global mean surface temperature after the climate system has reached a new equilibrium in response to a doubling of the CO2 concentration in the atmosphere
achilles	Asteroid No
land breeze	SEA BREEZE FRONT
chemical vapor deposition	Method for growing solids in which a gaseous precursor (containing fragments of the desired solid) is decomposed and deposited onto a desired surface
landé factor	The constant of proportionality relating the separations of lines of successive pairs of adjacent components of the levels of a spectral multiplet to the larger of the two J-values for the respective pairs
diurnal arc	The time expressed in right ascension that it takes a planet or degree of the zodiac to move from its rising point on the horizon to its setting point.
spectrum	A transmission grating consists of a large number of narrow, closely spaced bars
mail flag	See ‘postal flag’.
amplitude	(a) The maximum value of a varying quantity from its mean or base value
constellation	Imaginary pattern found among the stars, resembling animals, mythical heroes, and the like; different cultures map different constellations.
opposition	A second harmonic aspect, separating distance 180°
venn	A term (sometimes further divided into Venn A and Venn B) employed for the detailed classification of 17th Century English military colours, with particular regard to their use within a regiment (see also ‘colour 2)’, ‘colours 2)', ‘device 2)', ‘company colours' and ‘stand of colours1)').
mcmc	Markov Chain Monte Carlo -- Iterative simulations such as Markov Chain Monte Carlo make it possible to fit complex and more realistic Bayesian models to large and/or incomplete datasets.
manganese	Symbol:"Mn" Atomic Number:"25" Atomic Mass: 54.94amu
square	Fourth harmonic, 90°
m	milli- multiplier of one one-thousandth, e.g
polarity	Opposite signs effect each other: each sign has a relationship with its partner across the Zodiac.
eccentricity	a measure of how closely a planet's orbit approximates to a perfect circle
degrees	When gauging distance in degrees, hold your arm outstretched toward the sky: Image
revolution	One complete orbit or cycle
l-number	The orbital quantum number, which determines the magnitude of an electron's angular momentum
lambda boo stars	A-type stars with weak metallic lines, low rotational velocity and low radical velocity
sink	In general, a region where energy is given up, in contrast to a source, where energy is released
starlink	A software environment and suite of programs for astronomical data analysis developed in the UK and supported by the Rutherford-Appleton Labs
radius vector	In astronomy, an imaginary line connecting the center of an orbiting body with the centre of the body (or point) that it is orbiting
filling	DEGREE
exoteric astrology	any branch of astrology that studies observable events and characteristics such as natal astrology, mundane astrology, etc., as distinguished from esoteric astrology, which studies the unknown or occult aspects of humanity.
aviation weather center	NATIONAL SEVERE STORMS LABORATORY (NSSL)
open lozenge	See ‘voided lozenge'.
lanyard	1) In French military usage and in some others – and a translation of fourragère – the term for those cords and tassels that are worn on military uniforms to signify the award of a unit decoration, and may decorate that unit's military colour – see ‘cord 1)’ and ‘aiguillette' (also ‘colour 2)’, ‘cravat 1)’, ‘jack of honour’, ‘lanyard pennant’ and ‘tassels’)
t-cross	See T-square.
avogadro's number	(6.02 × 1023): The number of atoms in 12 grams of 12C; by extension, the number of atoms in a gram-atom (or the number of molecules in a mole) of any substance
mira variables	Cyclic variables with cycles 100-500 days, and of spectral types K, M, S and C
dysprosium	Symbol:"Dy" Atomic Number:"66" Atomic Mass: 162.50amu
chopping	The method of removing very large background signals at infrared wavelengths by alternating quickly from the object to nearby sky and back using a rocking motion of the telescope's secondary mirror
orbit	The path of an object that is moving around another object in space.
grand unified theory	(a) A mathematical scheme in which the electromagnetic, weak and strong nuclear forces are unified into a consistent description
multi-pinned-phase	Also multi-phase-pinned
midpoint	A zodiacal point in a horoscope that is equidistant from two planets
vehicular flag	See ‘car flag' and ‘fanion 2)'.
hertzsprung-russel diagram	a graph whose horizontal axis plots star color (or temperature) against a vertical axis plotting stellar luminosity (or absolute magnitude)
inclination	The angle between the orbital plane of an object and the equatorial plane of the parent object.
eddington approximation	An approximation used in the study of radiative transfer
cytosine	One of the five nitrogen-containing bases occurring in nucleotides.
wavelength	The distance between peaks of a wave.
satellite dish	Seriously? If you have been reading about satellite dishes on here this whole time, you had better know what it is!
anisotropic models	see Mixmaster Model
combined gas law	There came a time when scientists combined the ideas in Boyle's Law and Charles' Law
conservation of momentum	The principle that the linear momentum of a system (in Newtonian mechanics, mass times velocity) remains the same as long as no external force acts
statistical error	The uncertainty resulting from a measurement of purely random events
layered cross	A term that may be used to describe a cross whose horizontal arm differs in colour from its vertical as in the flag of the former Netherlands Antilles (see also ‘cross 1)’, ‘layered saltire’, ‘trinitarian cross’ and ‘tripartite').
proton	a positively charged particle that forms part of the nucleus of an atom
conductivity	Measure of how freely current can flow through a material
lava	molten rock that is erupted onto the surface of a planet and is hot enough to flow.
albedo features	These are regions on the surfaces of planets that contrast in brightness with nearby areas.
hysteresis	(a) The ability to follow two different branches of states, as a parameter built in the system varies first in a monotonic fashion and subsequently comes back to its initial value by varying in the opposite direction
julian day	a time period used in astronomical circles, defined as the number of days since 1 January, 4713 BCE (Before Common Era), with the first day defined as Julian day zero
et	Ephemeris Time [LLM96]
samarium	Symbol:"Sm" Atomic Number:"62" Atomic Mass: 150.40amu
luminosity	The amount of radiation given out by a star.
cyanogen bands	Molecular bands found in the spectra of stars of type G0 and later
nickel	Symbol:"Ni" Atomic Number:"28" Atomic Mass: 58.70amu
astronomical unit	Distance measure
celestial sphere	ECOLOGY
salpeter function	A simple functional interpolation for the distribution by mass of newly formed stars
gas	A state of matter without a definite shape or size, with the molecules (smallest particles of the gas) in nearly random motion
calendar	A system of reckoning time in which days are enumerated according to their position in cyclic patterns
seed nuclei	Nuclei from which other nuclei are synthesized
boson	(a) A particle which does not obey Pauli's exclusion principle
positively curved geometry	A geometry where parallel lines converge, sometimes called a spherical geometry.
temperature	RELATIVE HUMIDITY
messenger particle	Smallest bundle of a force field; microscopic conveyer of a force
spectroheliograph	Device with which spectra of the various regions of the Sun are obtained and photographed
supersynthesis	A radio interferometer system in which two synthesis aerials are used; one is static and utilizes the rotation of the Earth to provide a field of scan, the other is mobile
radiant	(adj) The heraldic term for rays that expand from a central point, but which may also be applied to other charges and to ordinaries that are similarly arranged – rayonné or rayonnant - but see ‘radiated’ and the note below (also ‘gyronny’, ‘ordinary’ and ‘radiating’).
laws of theermodynamics	Rules that govern the behavior of heat and other forms of energy
house cusp	The zodiacal degree at which a house begins.
hera	Unofficial name for Jupiter VII
latitude	The angular distance north or south from the Earth's equator measured in degrees on the meridian of a point: equator being 0 degrees and the poles 90 degrees North and 90 degrees South.
international date line	roughly follows the meridian at 180° longitude
right ascension	the angular distance around the sky parallel to the celestial equator; measured in hours h, minutes m and seconds s
chasma	Another name used to describe a canyon.
g$	Giga US Dollars
meridian	The imaginary line in the sky that extends from the southern point on the horizon through the zenith to the northern point on the horizon, bisecting the sky into an eastern and western half
relative number	See Wolf number
ecliptic	(a) Apparent linear path through the 12 constellations of the zodiac that the Sun seems to take during one Earth year, also representing therefore the "edge" of the plane of Earth's orbit
pan	Panchromatic sensor
ultraviolet	the portion of the spectrum with wavelengths just shorter than the bluest light visible
diffraction	The bending of light as it passes through a small slit or opening
sis junction	Superconductor-Insulator-Superconductor Junction
usgs	United States Geological Survey - USGS website USGS is a scientific organisation dedicated to studying the ecosystem and environment, natural hazards, and natural resources, and the impacts of climate and land-use change.
event	(a) A happenstance in the spacetime continuum referenced by three spatial coordinates and a complementary temporal ordinate
coordination polyhedron	Shape formed by a central ion and the surrounding ions of opposite charge
adenosine triphosphate	An energy-carrying molecule, found in a cell, that contains three phosphate groups, the sugar ribose, and the base adenine.
kleestengel	See ‘cloverstem(s)’.
albedo	surface reflectivity
drift	A wide, slow-moving ocean current principally caused by winds.
solar motion	The velocity of the Sun through space, relative to the Local Standard of Rest
sunspot	a dark area on the sun's surface that is cooler than the area around it
hardness points	Steel rods used by geologists to test the hardness of minerals and rocks.
national	Shorthand for the National Office, the AMC, or the AML.
geodesic	a path or line of shortest distance joining two points in space (or space-time)
dark nebula	A type of nebula that blocks light from sources behind it
type iib string theory	One of the five superstring theories; involves closed strings with left-right asymmetric vibrational patterns
solar flare	Sudden and dramatic release of a huge burst of solar energy through a break in the Sun's chromosphere in the region of a sunspot
locational astrology	The practice of casting a horoscope for the place in which a person resides, or would like to reside, rather than the place of birth
orbital inclination	Orbital inclination is the angle between the plane of an orbit and the plane of the ecliptic
butterfly effect	Any effect in which a small change to a system results in a disproportionately large disturbance
frame transfer	A CCD construction in which one half of the imaging area of the device is purposely covered with a mask opaque to light to provide a temporary charge storage section
cpt invariant	A theory is "CPT invariant" if for every possible reaction between subatomic particles, a reaction can also occur in which the electrical charges of the particles changed to their opposites, the mirror image of the particle trajectories is used, and the directions of motion are reversed
magnetic declination	Angle between the magnetic meridian and the geographic meridian at a given point.
heat	LAND BREEZE
anticenter	The direction of the sky (in Auriga) opposite to that toward the center of the Milky Way
horizon	The line that marks the Ascendant and Descendant
lattice	(a) A regular solids are characterized by the arrangement of the atoms on a set of regularly spaced points known as the lattice sites
chaos	a distinctive area of broken terrain
civil twilight	When the centre of the Sun is less than 6° below the horizon; normal daylight activities are possible.
kuiper belt	A disk-shaped region about 30 to 100 AU from the sun considered to be the source of the short-period comets.
opposition	Odin was the king of the gods...
chasma	a canyon
masthead streamer	See ‘streamer 2)’.
direct broadcasting satellite provider	A direct broadcasting satellite provider is a company that transmits a variety of channels to subscribers via satellite dish
m.c.	One of four major points in the birth chart and is at the top af the chart (beginning of the tenth house
air mass	SNOW LINE
noet owl	(Know it all) The IEM owl logo, designed and named by our members
absorption	causing large dark patches in regions of our Milky Way Galaxy and dark bands across other galaxies.
radial velocity	the movement of an object either towards or away from a stationary observer.
phase	The percentage illumination, from the observer's perspective, of an object (normally planet or Moon).
cosmic light	A small (no more than 1%) contribution by extragalactic sources to the background glow of the night sky
satellites	AVIATION WEATHER CENTER
triclinic crystal	A triclinic crystal has a shape in which the arrangement of facets is random.
fruitful signs	The water signs: Cancer, Scorpio and Pisces, which are associated with fertility.
compass	A compass is a scientific instrument that tells the user the direction of magnetic north
east point	The point on the celestial horizon 90° clockwise from the north point
digital information	Any form of information that comes in the form of (or can be converted into) discrete levels suitable for manipulation by a computer
ruthenium	Symbol:"Ru" Atomic Number:"44" Atomic Mass: 101.07amu
intercalation	The source of leap years, or the addition of an extra day or other period of time in order to reconcile the solar year with that of the calendar we use
optical fibres	Glass and transparent plastics can be made into very thin wires or fibers
curvature of spacetime	A notion associated with the description of spacetime in terms of Riemannian geometry
mole	A collection of 6.022* 1023 number of objects
forbidden	Processes can be naively imagined that might occur, but should not occur according to the predictions of the Standard Model
fantasy flag	See ‘fictional flag’.
critical density	The mass density needed to just halt the universal expansion.
type i string theory	One of the five superstring theories; involves both open and closed strings
degree	Angular measure, 1/360 of a circle.
orthorhombic crystal	A crystal in which the atoms are arranged in a rectangular solid, for which each of the three principal lengths are different
dignity	The sign that a planet rules naturally is its sign of dignity
s-electron	An orbital electron whose l quantum number is zero
velocity	A measure of both the speed with which an object is moving and its direction.
bl lac object	A member of a class of astronomical objects with the following characteristics: (1) rapid variations in intensity at radio, infrared, and optical wavelengths; (2) energy distributions such that most of the energy is emitted at infrared wavelengths; (3) absence of discrete features in low-dispersion spectra; and (4) strong and rapidly varying polarization at visual and radio wavelengths
echelle	A type of diffraction grating with groove angles of 90°
microphotometer	A device for measuring the variations in density in a photographic emulsion
accorné	See ‘attired'.
azimuthal quantum number	A measure of the minor axis of an elliptic orbital of an electron according to the Bohr-Sommerfeld theory
ultraviolet ga stars	A small group of Bp stars, which in the ultraviolet spectrum exhibit a strong 1414 line of GaII
diameter	The distance across a circle through its centre
milky way	The precise value of the Hubble Constant is unknown, although independent measurements have established the value of this constant to be between 50 and 80 kilometres per second per megaparsec (in other words, for every megaparsec, the object's velocity of recession increases by 50 to 80 km/s).
ytterbium	Symbol:"Yb" Atomic Number:"70" Atomic Mass: 173.04amu
reset noise	The unwanted and uncertain electrical signal transmitted to the output pin of a CCD during the process of recharging, via the reset transistor, the output storage capacitor to its preset value in readiness for the next pixel charge
optical tube assembly	This is the housing within which a telescope's mirror and optical surfaces are mounted.
parallax	the apparent change in position of two objects viewed from different locations.
sensitivity	Sensitivity is a measure of the minimum signal that a telescope can distinguish above the random background noise
inclined fly	A term used when the fly of a flag is cut diagonally so that the upper length of the flag is greater than its lower length – a type largely limited to Central Europe (see also ‘length 1)’, ‘schwenkel’ and ‘swallow-tail(ed)').
force carriers	Particles that act as the transmitters of forces
mass-radius relation	For any given mass less than the Chandrasekhar limit, there is a unique radius for a totally degenerate star
transit	(1) Passage of a planet across the Sun's disk; (2) any passage of a body with a small angular size across the face of a body with a large angular size.
tide	The periodic rise and fall of the surface of oceans, bays, etc., due principally to the gravitational interactions between the Moon, Sun and Earth.
fer de moline	See ‘millrind’.
electromagnetism	(a) One of the four fundamental forces of nature, governing the electric and magnetic interaction between particles
airy diffraction disk	The central spot in the diffraction pattern of the image of a star at the focus of a telescope
standard epoch	A date and time that specifies the reference system to which celestial coordinates are referred
katabatic wind	ANEMOMETER
sig	Special Interest Group: a means of bringing together Mensans who have a common interest in a specific subject
making colours	See ‘colours 5)’.
apocenter	The point in the orbit of one component of a binary system which is farthest from the center of mass of the system
cosmic	Constellation Observing System for Meteorology, Ionosphere and Climate
gravitational force	(a) The weakest of the four fundamental forces of nature, the gravitational force between any two masses is proportional to the product of the masses and varies inversely as the square of the distance between them
coulomb's law	The force between two charged particles varies directly as the size of the charges and inversely as the square of the distance between them
young	when used to describe a planetary surface, "young" means that the visible features are of relatively recent origin, i.e
ground loop	A condition in which two pieces of apparatus are connected together while each has a separate earth connection and these are not at identical potentials
tellurium	Symbol:"Te" Atomic Number:"52" Atomic Mass: 127.60amu
imperial broad pennant	See ‘broad pennant 4)’.
plage	bright regions seen in the solar chromosphere
asic	Application Specific Integrated Circuit
irreversibility	time-asymmetric evolution of an observable quantity of a physical system
padded emblem	See ‘raised detail'.
ss cygni stars	A subclass of dwarf novae
excomm	Executive Committee (see above).
cyclogenesis	BAROGRAPH
local arm	see Orion Arm [H76]
solid angle	(a) A measure of the angular size of an extended object, equal to the area it subtends on the surface of a sphere of unit radius
mcao	Multi-Conjugate Active Optics -- An active optics techniquefor increasing the resolution-emhance field of view in a terrestrial telescope, by compensating fo atmospheric turbulence simultaneously along several adjacent lines of sight
caboshed	See ‘appendix V’
hall effect	When an electric current is passed through a conductor and a magnetic field is applied at right angles, a potential difference is produced between two opposite surfaces of the conductor
zirconium	Symbol:"Zr" Atomic Number:"40" Atomic Mass: 91.22amu
esrf	European Synchrotron Research Facility [LLM96]
gauge invariance	this would be better called `local phase-angle independence'
electron temperature	The temperature that appears in the Maxwell distribution of velocities for electrons
solstice	The solstice is one of the two points of the ecliptic farthest from the celestial equator; one of the two points on the celestial sphere occupied by the Sun at maximum north or south declination
tdrss	Transmission Data and Relay Satellite System
magnetosphere	The area around a planet most affected by its magnetic field
seismology	Study of vibrational waves passing through planets, revealing internal structure.
right ascension	Longitude lines projected onto the celestial sphere
vlt	Very Large Telescope [LLM96]
integrated circuit	A small electronic component made of semiconductor silicon on which an entire electronic circuit of numerous microscopic transistor amplifiers, diodes and resistors has been constructed
rydberg atom	extremely highly excited atoms are called Rydberg atoms (Rydberg was an early systematizer of atomic spectra)
time zone	longitudinally defined regions on the Earth that keep a common time
parallax	The apparent shift of an object against its background when viewed from different locations
geometry	The mathematics of lines drawn through space
dorsum	a ridge
quadrant	One of the four sections of a horoscope, each bounded by two angles not opposite each other.
cosmological principle	This principle states that the distribution of matter across very large distances is the same everywhere in the universe and that the universe looks the same in all directions
density parameter	The ratio of the mean mass density of the local universe to the density required to just halt the universal expansion, given the symbol Omega(0).
nanometre	A billionth of a metre, which is written scientifically as 10^–9m.
tcp	Transmission Control Protocol
beta decay	(a) The process in which a neutron disintegrates into a proton, an electron, and an antineutrino
environment	POSITIVE VORTICITY ADVECTION
tack pin	See ‘belaying pin’.
ises	International Space Environment Service
brillouin zone	A continuous ensemble of all energies and wave functions which may be obtained from one atomic energy level in a metallic-crystal lattice
bias frames	An extremely short exposure from a CCD camera or DSLR
anastigmastic lens	A lens designed so as to minimize its astigmatic aberration
solar cycle	The approximately 11-year quasi-periodic variation in frequency or number of solar active events.
ellipse	A conic section; the curve of intersection of a circular cone and a plane cutting completely through the cone.
visibility	AFOS
cavitation	The formation of small cavities in a liquid, caused by a reduction in fluid pressure
attractor	(a) A mechanical system may be such that its dynamical evolution causes it to approach a stable end-state
great red spot	A very large storm, technically a high pressure anticyclone, on the planet Jupiter.
composite chart	Two individual charts which are merged to form one
fahrenheit temperature scale	A temperature scale on which the freezing point of water is 32° F and the boiling point is 212° F.
conic constant	A number used in optics to specify the shape of a surface which is a conic section, i.e
cosmology	The study of the structure of the universe
strontium	Symbol:"Sr" Atomic Number:"38" Atomic Mass: 87.62amu
cosmic -ray bursts	Short (about 0.1-4 s), intense, low-energy (about 0.1-1.2 MeV) bursts, first recorded by the Vela satellite system on 1967 July 2, but not declassified until 1973
star cluster	a large grouping of stars, from a few dozen to a few hundred thousand, that are bound together by their mutual gravitational attraction.
missing mass	The cosmic mass that some scientists hypothesize so that the Universe will have the critical density of matter, with an exact balance between gravitational energy and kinetic energy of expansion
attitude	Position of a rocket with respect to the horizon or some other fixed reference plane
indefiniteness	the suspension of an eventuality between truth and falsity, or of a physical variable among its possible definite values, which occurs, according to quantum mechanics, in certain states of a system
electromagnetic radiation	For amateur photography, CCDs are light-sensitive arrays that can record the amount of light coming in
visible light	wavelengths of electromagnetic radiation that are visible to the human eye.
emission	The process of transition of an electron from an outer orbit to an inner orbit around the nucleus results in a characteristic amount of energy being radiated (as line emission) that corresponds to the lost energy of the electron
impact parameter	A measure of the distance by which a collision misses being head-on
gps	Global Positioning System
wavelength	Light energy travels in waves, or pulses
solar system	Any system of planets and other objects in orbit around a star
gui	Graphical user interface
ides	name of a certain day of the month of the
debruised	A heraldic term used in place of ‘surmounted by’ particularly when a charge or ordinary (which may or may not touch the field) is being placed over an animal – but see ‘surmounted, by’ (also ‘charge 1)’, ‘ensigned’, ‘ordinary’ and ‘overall 2)’).
acid	In chemistry, a substance that may have a sour taste, makes blue litmus paper turn red, and can react with a base to make salt
interstellar square law	Decreasing as one over distance squared (1/r2), where r is the distance from the source
stat-coulomb	The unit of charge in the cgs electrostatic system
satellite	small object, natural or artificial, that orbits a larger object.
shortwave radiation	Shortwave radiation is another name for the radiation emitted by the Sun and received by the Earth
weinberg-salam model	(a) An alternative name for the Electroweak Theory
epr	Abbreviation of A
self-consistent field approach	An approach in which the density distribution and state of motion in a system are determined so as to be self-consistent with the force field (e.g., gravitational or electromagnetic) arising from the system itself
merf	Mensa Educational Research Foundation
asteroid	a rocky object in space that can be a few feet wide to several hundred miles wide
getter	A chemical absorption method of removing (pumping) gas from a chamber by tying up molecules on a surface
baryon number conservation	The principle that the number of baryons must remain the same in any nuclear reaction
relaxation	The process of gravitational interaction (in the case of a cluster of stars or galaxies) whereby a random distribution of motions is eventually established
convection	Transfer of thermal energy via fluid currents (gases or liquids).
kwf	Keyword file of events listing DSN station activity.
bolometric absolute magnitude	A measure of the total amount of energy radiated by a star at all wavelengths
occultation	The passage of one object in front of a smaller one, temporarily obscuring all or part of the background object from view.
anti-ferromagnet	a solid in which the spins of neighboring atoms are oppositely aligned
temperature	In astronomy, temperature is measured with the Kelvin scale (symbol K) which is equal to °C + 273°
radio meteor detection	The detection of meteors using radio wavelengths and equipment
space curvature	The curvature of three-dimensional space; one of the consequences of general relativity
gem	See Castor
spectrograph	A device that measures the wavelength of light, known as its spectra, and then displays the results as a graph.
geodesic	the shortest (or longest) path between two points
mips	Millions of Instructions Per Second -- A computer benchmark
hubble constant	The constant H0—discovered in 1925 by Edwin Hubble—determines the relationship between the distance to a galaxy and its velocity of recession due to the expansion of the Universe
azimuth	the angular distance of an object around or parallel to the horizon from a predefined zero point.
sonde	A rocket or balloon carrying instruments to probe conditions in the upper atmosphere
electromagnetic radiation	) Only a small fraction of the infrared light coming from astronomical objects can go through the Earth's atmosphere: to detect the full range of infrared wavelengths a space telescope is needed
achondrite	a stony meteorite representing differentiated planetary material.
face	An obsolete term meaning the division of each sign into six equal parts of 5° each.
cadent	The 3rd, 6th, 9th and 12th Houses of a chart are known as the Cadent Houses
halocarbons	Halocarbons are organic compounds in which one or more carbon atoms are linked with one or more halogen atoms (fluorine, chlorine, bromine or iodine).
antenna	The part of a radio telescope responsible for detecting an electromagnetic wave
einstein coefficient	An emission (or absorption) coefficient
ozone hole	A region of the Earth's atmosphere over Antartica where the concentration of ozone is abnormally low.
chart	A horoscope.
r coronae borealis stars	A class of very luminous helium-rich, carbon-rich, hydrogen-poor eruptive variable supergiants
russell-vogt theorem	The theorem stating that the equilibrium structure of a star is determined by its mass and chemical composition.
hatchment	See ‘achievement 2)’.
contact potential	Potential difference that arises at the junction of two different conducting materials
carborundum	A brand name for the commercial abrasive used by amateur telescope makers to grind mirrors.
spark chamber	A means of detecting high energy particles by the trail of ionizations left as they pass through a chamber containing many charge plates
localisation	the wave-function of an electron is said to be localized if it is confined to a small region of a large system rather than being extended through the system
stratosphere	The region of Earth's atmosphere immediately above the troposphere
gauss	(a) The cgs unit of magnetic flux density
metar	SANDSTORM
cretaceous-tertiary impact	The impact of one or more asteroids or comets, up to about 10 km in size, about 65 million years ago, which apparently led to extinction of most species of plants and animals living at that time, including dinosaurs.
garvey colors/colours	The colours introduced by Marcus Garvey in 1917 and designed to represent African-American heritage; they were internationally adopted in 1920 and are now used on several national flags – flags – the black liberation or Afro-American flag or colours - but see ‘pan-African colours’.
mesocyclones	HIGH CLOUDS
g	G is an asteroid's "magnitude slope parameter." It is specific to an asteroid and is used for the apparent magnitude computation (as the asteroid moves in relation to the Earth).
regolith	A powdery soil layer on the Moon and some other bodies caused by meteorite bombardment.
hydrogen-beta filter	This filters out all light except that of the hydrogen-beta line that has a wavelength of 486.5nm
vv cephei stars	Eclipsing binaries with M supergiant primaries and blue (usually B) supergiant or giant secondaries
no	National Office: aka ‘National’
lane-emden equation	A second-order nonlinear differential equation describing the structure of polytropes
absolute zero	the lowest possible temperature, at which substances contain no heat energy, and atomic movement has stopped
balzaus	See ‘bauceant’.
field rotation	The rotation of a star field about the center which occurs in an alt-az telescope because the motion is not about the polar axis
lithium	Symbol:"Li" Atomic Number:"3" Atomic Mass: 6.94amu
gamma-ray burster	The theoretical interpretation is unclear, but these sources display erratic bursts of high energy gamma-rays and no preference for the disk of the galaxy.
sidereal time	(ST) The measure of time defined by the apparent diurnal motion of the catalog equinox; hence a measure of the rotation of the Earth with respect to the stars rather than the Sun
metar	DUST BOWL
solar velocity	Velocity of the Sun (19.4 km sin the direction lII = 51°, bII = 23°) with respect to the local standard of rest
minimal surface	A mathematical term referring to surfaces that satisfy a minimization procedure
entrance pupil	The real object or image which defines the limit of valid light paths through an optical system
zenith	Odin was the king of the gods...
jcomm	Joint Commission for Oceanography and Marine Meteorology
afflicted	Unfavorable planetary aspect: Squares, Oppositions and Quincunxes.
quincunx	A minor Aspect wherein planets are approximately five signs apart, or 150 degrees
selection effect	Any effect that systematically biases observations or statistics away from a correct understanding.
crossing time	The time it takes a particle to travel from one point in its orbit to another point 180° away
new general catalogue	The New General Catalogue is a listing of almost 8000 of deep-sky objects.
v1016 cygni	A peculiar emission object (in optical, radio, and infrared), possibly a symbiotic star
earth signs	Taurus, Virgo, and Capricorn, which belong to the earth triplicity, symbolizing "earth" qualities such as stability, solidarity and practicality.
many-worlds	Everett-Wheeler interpretation of quantum mechanics: The view of quantum mechanics holding that a physical system simultaneously exists in all of its possible states prior to and after a measurement of the system
galactic rotation curve	The orbital speed of an object as a function of distance away from the center of a galaxy.
inarticulate signs	Aries, Taurus, Leo and Capricorn, signs pictured as animals that have voices but lack the power of speech, symbolizing an inability to communicate
singularity	A point in space and time where gravity (amongst other things) becomes infinite and the laws of physics break down.
covalence	Covalence is the ability of an element to bond with other elements by sharing electrons across a bond
wedge	See ‘pile 3)’.
monoclinic crystal	A crystal that has a shape like a cube but is flattened in one dimension
semi-major axis	Half the distance of an ellipse's maximum diameter, the distance from the center of the ellipse to one end.
path	The projection of the line of motion of a meteor against the background of the celestial sphere, as seen by the observer
irs	Infrared source
fahrenheit	ABSORPTION
hierarchical clustering model	A model of galaxy clustering in which different patterns appear at different scales of distance and in which the "average" density of matter depends on the size of the volume over which the average is performed
strain	The fractional change in dimension produced by a stress applied to a body
cte	Charge Transfer Efficiency A term used to characterize the amount of charge successfully moved from pixel to pixel in a CCD
crescent	The phase of a body that is less than one-half illuminated.
bragg angle	Glancing angle between an incident X-ray beam and a given set of crystal planes for which the secondary X-radiation from the planes combines to give a single reflected beam
lenz's law	The current induced by an electromotive force will appear in such a direction that it opposes the charge that produced it
environment	EDDY
stone meteorite	a meteorite which resembles a terrestrial rock and is composed of similar materials.
asymptotic freedom	(a) A term used to describe the observed decrease in the intrinsic strength of the color force between quarks as they are brought closer together
tdb	Barycentric Dynamical Time
dose equivalent	The dose equivalent is a somewhat magical dose unit that in theory makes different radiations appear to be equally effective in producing biological effects in a given organ of the body even though the radiations may not be equally effective
cumulate	Rock composed of crystals that have grown and accumulated (often by settling) in a cooling magma chamber.
recombination radiation	See radiative capture
t tauri stars	Late type irregular variables associated with bright or dark nebulosity
year	TROPICAL AIR MASS
infrared	(a) That part of the electromagnetic spectrum that lies beyond the red, having wavelengths from about 7500 Å to a few millimeters (about 1011-1014 Hz)
ecliptic	It is divided in twelve roughly equal parts by the 12 Zodiac constellations that play an important role in Astrology.
advection	The transfer of matter such as water vapor or heat through the atmosphere as a result of horizontal movement of an air mass
random process	A process in which the timing of an individual event is unpredictable, even though the rate of events may be well-determined
zodiacal light	a faint cone of light rising from the horizon after sunset or before sunrise; it is caused by sunlight reflected from thinly spread interplanetary material lying in the main plane of the Solar System
nobelium	Symbol:"No" Atomic Number:"102" Atomic Mass: (259)amu
geocentric theory	Odin was the king of the gods...
open system	a system communicating with the environment by the exchange of energy and matter.[D89]
curve of growth	The relation between the equivalent width of an absorption line and the number of atoms that produce it
sphere of gravitational influence	The region in which the gravitational influence of a body is the dominant influence on a passing small body's motions.
m	(a) Spectral type for red stars, such as Betelgeuse, Antares, and Proxima Centauri
string mode	A possible configuration (vibrational pattern, winding configuration) that a string can assume
emissivity	A measure of the efficiency of a source to radiate like a perfect black body; 0% is perfectly black and 0% is perfectly reflecting
sesquiquadrate	Minor Aspect in which the planets are less than three signs apart, or 135 degrees
space-time	the four-dimensional description of the universe in which length, breadth, and height make up the first three spatial dimensions, while time makes up the fourth dimension
season	A particular time of year which has a certain type of weather
technetium	Symbol:"Tc" Atomic Number:"43" Atomic Mass: (98)amu
shock wave	A sharp change in the pressure, temperature, and density of a fluid which develops when the velocity of the fluid begins to exceed the velocity of sound
satellite	A satellite is an object that moves around a larger object
semi-decile	The twentieth harmonic, 18°; interpreted as a weak minor easy aspect
veering	BACKSCATTER
synastry	Comparing natal charts to find strengths and weaknesses in the area of compatability.
richardson-lucy method	An image reconstruction algorithm
tutorial on twilight	UUmbra: (i) The shadow that results when a bright object is completely occulted
east point	The equatorial Ascendant; i.e., the sign and degree rising over the eastern horizon at Earth's equator at any given time; the point at which Earth's equator intersects the ecliptic.
x particle	Exceedingly massive (hypothetical) particle predicted by grand unified theories to convey a very short-ranged interaction between quarks and leptons
buried channel	A construction in a silicon CCD which results in a collection zone for photo-generated electrons which is buried well below the surface of the silicon
carbonate	a compound containing carbon and oxygen (i.e
fk	Fundamental Katalog [LLM96]
handguard	In Spanish military usage and possibly some others, a metal guard fixed to the staff of a military colour so as to protect the bearer's right hand (originally in combat) – a gardamano (see also ‘colour 2)', ‘colours 2)' and ‘staff 2)').
symmetry	The idea that diverse physical phenomena have a simple underlying basis; one of the basic assumptions of modern science.
bolometric correction	The visual (or photovisual) magnitude minus the bolometric magnitude of a star
conservative system	(a) A system in which total energy is conserved in time, and the evolution of the observable properties is indifferent with respect to the direction of time
equator	Great circle on a sphere, at the same distance between the two poles.
miller-urey experiment	An experiment conducted by Stanley Miller and Harold Urey at the University of Chicago in 1953 that simulated the conditions on the early Earth
second quantization	This goes beyond the quantum theory of Heisenberg and Schrödinger by applying the act of quantization a second time
st george’s ensign	In English later British RN usage now obsolete, the term to describe a white ensign charged with a Cross of St George overall (as per the present pattern), and formerly used in order to differentiate it from one having a plain fly (see also ‘canton of St
territorial flag	See ‘sub-national flag’.
chromite	Cr-Fe oxide, Cr2FeO4, found in many meteorite groups.
rvc	Regional Vice-Chair
celestial sphere	This is the name given to the projection of the night sky on to an imaginary sphere around the Earth
oao	Orbiting Astronomical Observatory [LLM96]
metric	(a) The metric gives the spacetime interval de between two neighboring events
regge-wheeler equations	Schrödinger-type equations for small, odd- parity perturbations on the Schwarzschild metric
great year	The astrological ear based on the time it takes Earth's axis to complete on revolution around the pole of the ecliptic, about twenty-five thousand years
secular instability	Instability caused by the dissipation of energy
chronometer	A highly accurate timepiece
mdd	Meteorological Data Distribution
ip	Internet Protocol
geocentric coordinates	The latitude and longitude of a point on the Earth's surface relative to the center of the Earth; also celestial coordinates given with respect to the center of the Earth
thermodynamic equilibrium	(a) The state reached ultimately by an isolated system.[D89] (b) The condition of a system whose members have conformed to the principle of equipartition of energy, so that there is no net exchange of energy
fin flash	A term for the national colours (or sometimes the national flag/an emblem therefrom) when painted as a symbol of nationality on the tail plane/fin of largely (but not exclusively) military aircraft - a fin marking or rudder stripes (see also ‘fuselage marking(s)’, ‘aircraft marking(s)’, ‘flag emblem', ‘roundel 1)’, ‘national colours 2)’, and ‘wing marking(s)’).
frequency	It is the number of oscillations per second of a vibrating system.
appointed officers	Officers appointed at the discretion of the Board to fill non-voting positions
birthchart	A diagram showing the exact positioning of the planets in the signs at the moment of birth.
culmination	the maximum altitude of a celestial body from the celestial equator
hubble nebula	A cometary nebula whose apex star is R Mon
beamsplitter	This is an optical component of a bino viewer that splits the light coming into the eyepiece holder into two beams for viewing.
chaos	A distinctive area of broken terrain.
line broadening	Increase in the range of wavelengths in which some characteristic emission or absorption occurs, due to a number of causes (e.g., Doppler broadening, the effects of perturbers, etc.)
ecosphere	The area around a star where it is just the right temperature for life to exist.
dissociation	Breaking down of a compound into its components to form ions from an ionic substance.
moving cluster	A group of stars dynamically associated so that they have a common motion with respect to the local standard of rest
sphere	Anything in the shape of a ball
gamma-ray bursts	See cosmic gamma-ray bursts
mare	The maria on the Moon are regions where viscous lava has flowed over the surface
meridian	The Meridian at Greenwich
toroidal radius	in a solar loop structure, it is the distance from the axis of the loop to the center of the "semi-circle" that the loop forms
uniform vibration	The overall motion of a string in which it moves without changes in shape
apsidal motion	Rotation of the line of apsides in the plane of the orbit; (in a binary) precession of the line of apsides due to mutual tidal distortion
bandpass filter	A device used in radio astronomy for suppressing signals of unwanted frequencies without appreciably affecting the desired frequencies
ubvri	Designations for parts of the optical waveband, isolated by means of special glass filters which eliminate the unwanted regions, and used for standard astronomical intensity measurements
saint andrew’s ensign	See ‘St Andrew’s cross 3)’ above.
harmonic oscillator	Any oscillating particle in harmonic motion
land breeze	NOR'EASTER
waterspout	LAPSE RATE
tachocline	A thin boundary that separates the Sun's outermost layer, called the convective zone, from the denser internal regions
maksutov telescope	A reflector whose primary mirror is spheroidal instead of parabolic
titanium	Symbol:"Ti" Atomic Number:"22" Atomic Mass: 47.90amu
static limit	In the Kerr solution to Einstein's equations, a surface on which a particle would have to travel at the local light velocity in order to appear stationary to an observer at infinity, and just inside which no particle can remain stationary as viewed from infinity
heisenberg model	A model of magnetic systems in which each magnetic atom has a spin which is free to point in any direction in space
biasing	A hypothesized feature of the condensation of galaxies out of a background medium of gas
ln2	The symbol for Liquid Nitrogen
spherical aberration	see Aberration
coordinate system	A system used to identify locations on a graph or grid
arc-second	Angular measure, 1/3600 of a degree.
eukaryote	Cell with a nucleus, that is, with DNA contained by an interior membrane; a multicelled organism
sunspot	A magnetic disturbance on the Sun's surface that is cooler than the surrounding area.
hydrogen-deficient c-type stars	A subgroup of high-luminosity C stars with weak or absent hydrogen lines, mostly of types F and G
luminance	This is the name often given to the ‘light frames' or exposures gathered from a monochrome CCD i.e
higgs physics	This is the combined physics that explains the origin of the Higgs field, the reason the Higgs mechanism applies, and the properties and study of the Higgs bosons
orbit	The path of a body that is in revolution about another body or point.
galaxy	distinguished by a straight bar of stars, gas and dust that cut through the center of the galaxy and then trail off in a spiral pattern.
radiation length	The mean distance traveled by a relativistic particle in a given medium before its energy is reduced by a factor e by its interaction with matter
peregrine	From the Latin peregrinus, foreigner
aphelion	Furthest point from the Sun in the orbit of a body revolving around the Sun.
synoptic-scale	MESOSCALE CONVECTIVE COMPLEX (MCC)
e-folding time	The time within which the amplitude of an oscillation increases or decreases by a factor e (e = 2.718...)
grand cross	Configuration in which four planets form mutual squares
infinities	Typical nonsensical answer emerging from calculations that involve general relativity and quantum mechanics in a point-particle framework
embraced	See ‘interlaced’.
condensation	EVAPOTRANSPIRATION
tungsten	Symbol:"W" Atomic Number:"74" Atomic Mass: 183.85amu
co	see Carbon Monoxide
hydrosphere	The hydrosphere is the water on and underneath the Earth's surface (ocean, seas, rivers, lakes, underground water)
mons	mountain (plural is montes)
universal coordinated time	replaced GMT as the world reference for time
polonium	Symbol:"Po" Atomic Number:"84" Atomic Mass: (209)amu
eclipse	effect caused by one body casting a shadow on another
degree	1/360 of a circle.
meteor	the bright, transient streak of light produced by a piece of space debris burning up as it enters the atmosphere at high speed
epicycle	A small circular motion superimposed on a larger circular motion.
critical mass density	(a) The value of average cosmic mass density above which the Universe is closed
stokes parameters	(a) A way of characterizing the polarization state of light which is closely related to actual measurements
king’s broad pennant	See ‘broad pennant 4)’.
fields	Entities dispersed in space but having a measurable value or magnitude that can be measured at any point in space
anomalous dispersion	The refractive index of a transparent medium normally increases as the wavelength is reduced
bad nuclei	Balmer-Absorption Dominated (BAD) Nuclei
sunspots	Areas of the Sun's surface that are cooler than surrounding areas
greenhouse effect	increase in temperature caused when incoming solar radiation is passed but outgoing thermal radiation is blocked by the atmosphere (carbon dioxide and water vapor are the major factors)
anomaly	An angular value used to describe the position of one member of a binary system with respect to the other
balk cross	An accurate but seldom used translation (balken meaning a "balk, "bar" or "beam" of wood) of the German term balkenkreuz - see ‘balkenkreuz'.
adaptive optics	Compensating for atmospheric distortions in a wavefront by high-speed changes in the shape of a small, thin mirror
orbit	The closed path of one object around another.
ejecta	Material blown out of a crater during an impact on the surface.
clocking	The process of raising and lowering the voltages between two levels - high and low - on the electrodes or gates of a CCD in order to move charges from one pixel to the next
transit telescope	A stationary support structure for a telescope
train	a glowing path left in the wake of a passing meteor
ascendant	The Rising Sign
bosonic string theory	First known string theory; contains vibrational patterns that are all bosons
fluctus	flow terrain
lan	Local Area Network -- A means of interlinking computers
causality	pertaining to the time development of a system and the requirement of special relativity whereby energy cannot be propagated at a speed faster than that of light
space motion	Velocity of a star with respect to the Sun; hypotenuse of the right triangle formed by its radial and tangential velocities (cf
lyrae stars	A class of eclipsing binaries whose secondary minima are intermediate between those of Persei and those of W UMa
aura	A subtle quality or atmosphere emanating form a living being, object, or place.
a shell stars	A-type stars in which two different types of line profiles co-exist
miras	Microwave Imaging Radiometer using Aperture Synthesis
bernoulli probability	See binomial probability
rille	A long, narrow depression on the surface of the Moon – and other planetary bodies – that resembles a channel
curvature constant	A constant (k) appearing in the Robertson-Walker metric that determines the curvature of the spatial geometry of the Universe
sec	Secondary Electron Conduction [LLM96]
inflationary cosmology	Modification to the earliest moments of the standard big bang cosmology in which universe undergoes a brief burst of enormous expansion
rotational invariance	The property of being unchanged by a rotation
feghoot	A shaggy-dog type joke with a pun as the punch line; for example, "Pardon me, Roy, is that the cat who chewed your new shoes?"
greenwich	Site now in London of the first Royal Greenwich Observatory, designed and built by Christopher Wren in 1675
diastolic	A measurement of the amount of pressure on the walls of blood vessels when the heart is at rest.
kelvin scale	the `natural' or `absolute' scale of temperature, on which the value of temperature corresponds roughly to the typical thermal energy
newton's laws of motion	Three rules describing motion and forces
wavelength	The distance that a wave from a single oscillation of electromagnetic radiation will propagate during the time required for one oscillation.
angular diameter	The apparent size of an object on the sky
cathode	Electrode where electrons are gained (reduction) in redox reactions.
salinity	FREEZING PRECIPITATION
latitude	Angular distance from the equator in a system of spherical coordinates.
owl	The unofficial mascot of Mensa (the owl was sacred to Athena, Greek goddess of wisdom)
air signs	Signs possessing the qualities of the element Air: intellect, thought process etc
main beam	The lobe of maximum sensitivity in a radio telescope
cosmic strings	(a) Thin, massive, thread-like objects that are predicted to exist by some, but not all, grand unified theories; they have a thickness of about 10-29 cm and a mass of about 1022 g cm-1, or 107 Solar masses per light-year: they could be produced copiously in a random arrangement in the early Universe and might play an important role in the formation of galactic structure
bohr radius	(a0 = 2 / me2) (a) The radius of the orbit of the hydrogen electron in its ground state (0.528 Å)
40 eridani	A nearby triple system, 5 pc distant
major shower	A meteor shower with a Zenith Hourly Rate (ZHR) of greater than 10 per hour.
rossiter effect	A rotational distortion of the velocity curves of eclipsing binaries
constellation	a group of stars that form a pattern or shape in the night sky
hermetic	Of or relating to Hermes Trismegistus, a mythical philosopher beloved of the Neoplatonists and usually identified with ancient Egypt
pinch effect	collapsing or indrawing of electric fields in a plasma or similar current carrying material which can create a more intense plasma reaction
spiral arm	In spiral galaxies, one of the arms lying at an angle to the Sun-center line
geodetic coordinates	The latitude and longitude of a point on the Earth's surface determined from the geodetic vertical (normal to the specified spheroid)
mass-shell	In quantum mechanics, a particle's energy and momentum are essentially independent of each other
cvd	Chemical Vapor Deposition [McL97]
cdt	US Central Standard Time, i.e
voids	Low-density regions in the large-scale distribution of galaxies.
lorentz contraction	(a) Diminution in the observed length of an object along the axis of its motion, as perceived by an external observer who does not share its velocity
s-matrix	The S-matrix relates the incoming and out-going states of elementary particles during interactions and scattering experiments
plunge	In describing the tracking motion of an AZ-EL or ALT-AZ mounted radio telescope, to "plunge" means to exceed 90° in elevation and then to continue tracking as elevation decreases on the other side without swiveling around in azimuth
lava	Molten rock that erupts to Earth's surface through a volcano or a fissure.
celestial co-ordinates	A system by which the position of a body on the celestial sphere is plotted with reference to a reference plane and a reference direction
helicity	(a) The projection of a particle's spin along its direction of motion
galactic rotation	The revolving of a galaxy round its central nucleus even as it continues its proper motion
sun spots	Dark patches on the Sun's surface.
axis	An imaginary straight line on which an object rotates.
atsr	Along Track Scanning Radiometer
lan	Local area network for inter-computer communications.
atom	. The symbol for Angstrom is à….
penumbra	The area of partial illumination surrounding the darkest part of a shadow caused by an eclipse.
free spectral range	A term used in spectrometers to indicate the wavelength interval between occurrences of the same wavelength produced in the next order of interference or diffraction
stress	When a system of opposing forces acts on a body the material is subject to some form of stress
satellite	Any small body orbiting a larger body.
meridional flow	Flow between the poles, or between the equator and the poles
monotonic	Either continuously increasing or decreasing
crossover effect	(a) A term applied to the observation in magnetic stars that line profiles are definitely sharper in circularly polarized light of one sense than in that of the other
great circle	A circle formed on the surface of a sphere which is formed by the intersection of a plane which passes through the centre of a sphere
triple- process	see 3 process
eccentricity	Parameter of an ellipse that characterizes its flatness
retrograde loop	Odin was the king of the gods...
line of nodes	Odin was the king of the gods...
mutation	The fundamental mechanism for generating change in genetic material
quantum liquid	a system of particles which are both sufficiently mobile and at sufficiently low temperature to display the effects of quantum-mechanical indistinguishability
axis	An imaginary line through the center of a planet or a satellite around which it rotates.
tornado	WHITEOUT
ozone	UNDERCAST
chemical changes	Processes or events that have altered the fundamental structure of something.
precipitation	SEA SPRAY
obliquity of the ecliptic	Refers to the angle between the planes of the Earth's orbit and Celestial Equator.
meteor shower	(a) A profusion of meteors that fall within a period of a few hours and that appear to radiate from a common point in the sky
explosive eruption	a dramatic volcanic eruption which throws debris high into the air for hundreds of miles; lava is low in silicate; can be very dangerous for people near by; an example is Mount St
saw	Surface Acoustic Wave, refers to a device in which acoustic waves propagating on the surface of a piezo-electric crystal transfer a signal between two transducers
meniscus mirror	A very thin mirror with a high curvature
irradiation	(a) An optical effect of contrast that makes bright objects viewed against a dark background appear to be larger than they really are
tide rip	Small waves formed on the surface of water by the meeting of opposing tidal currents or by a tidal current crossing an irregular bottom
pri	Pulse Repetition Interval, the interval between radar pulses.
aperture function	In radio astronomy, a distribution of direction assignments applying to a uniform background
molad	a cyclic
cambridge flag	See ‘continental colours’.
edr	Experiment Data Record.
urinant	See ‘appendix V’.
configuration	Usually refers to a pattern of Aspects in the horoscope.
rift	a fracture or crack in a planet's surface caused by extension
escape velocity	The speed an object must have in order to escape from another object's gravity.
conductor	Material with low resistivity
sunspot radiation	Intense, variable, circularly polarized radio waves in a noise storm
bipm	Bureau International des Poids et Mesures
electromagnetic spectrum	Complete range of wavelengths which light can have
intensity	A measure of the rate of energy transfer by radiation
airglow	The natural glow of the night sky due to reactions that take place in the Earth's upper atmosphere.
protostar	The initial stage of stellar formation
thermal background	The radiation emitted by the telescope and the atmosphere at infrared wavelengths due to the heat (temperature) of the source
lunar limb	The extreme edge of the disc of the Moon.
biology	The branch of science devoted to the study of living systems.
standard error	A measure of the uncertainty in a single measurement, based on a scatter of multiple measurements of the same quantity
boundary condition	(a) Restriction on the limits of applicability of an equation
solar seismology	The study of natural vibrations and oscillations in the Sun as a way to probe the structure of the solar interior.
promontorium	cape; headland
higgs field	(a) Mechanism operating in symmetry-breaking events; in electroweak theory, the Higgs field is said to have imparted mass to the W and Z particles
hierarchical clustering	The process by which a system of self-gravitating particles will gradually aggregate into larger and larger gravitationally bound groups and clusters
special relativity	(a) Einstein's theory of time and space, formulated in 1905, which shows how measurements of length and time differ for observers in relative motion
differentiation	Any process that tends to separate different chemicals from their original mixed state and concentrate them in different regions.
universe	The realm of the universe is everything in existence.
anti-reflection coating	Also AR coating
photosynthesis	Process that converts sunlight into stored chemical energy, essential for the proliferation of advanced forms of life.
hourglass nebula	A compact H II region in the center of M8
conservation of angular momentum	the law of science that states that momentum must be conserved within a system
cosmogony	The study of the origin of celestial systems, especially the Solar System
barred spiral galaxy	A galaxy with a “bar” of stars and interstellar matter, such as dust and gas, slicing across its center
events	An event is any activity scheduled by and for Mensa members and published in the newsletter
bus	The general term for hardware for dealing with the input-output pathway and backplane of a computer
europa	The second moon of the planet Jupiter with an icy crust covering a saltwater ocean
canadian pale	A term used when the central stripe in a vertical triband has internal proportions of 1-2-1 as in the Canadian national flag – but see note below and ‘unequal triband’ (also ‘proportions 2)’, ‘pale’, ‘triband’ and ‘tricolour’).
equinox	The equinox is both a location and a time of year
sinus	literally "bay"; really a small plain
julian date	also called Julian Day Number
e component	see L Component
red giant tip	The upper tip of the red-giant branch in the H-R diagram
iron peak	A maximum on the element-abundance curve near atomic mass number 56
cytherean	An adjective used to describe things related to the planet Venus
cno tri-cycle	Similar to the CNO bi-cycle, with the addition of the cycle 17O(p, )18F( +)18O(p, )15N
airglow	The background light in the night sky caused by the atmospheric scattering of man-made light.
b band	See Fraunhofer lines
geological time scale	The sequence of events in the history of the Earth.
distillation	Distillation is a process in which one substance is boiled away from another and then collected
atomic number	(a) The number of protons in an atom's nucleus
fraunhofer lines	the dark lines in the spectrum of the sun
q0	The cosmological deceleration parameter.
rosseland mean absorption coefficient	A coefficient of opacity which is a weighted inverse mean of the opacity over all frequencies
domal dignity	See dignity.
fresnel diffraction	Diffraction observed when either source or screen (or both) are close to the diffractor
false vacuum bubble	A bubble which has false vacuum on the inside, and true vacuum on the outside
birth sign	See astrological sign.
natural selection	The theory that states that those individuals best adapted to the ever-changing environment produce a greater number of offspring.
fg sagittae	A supergiant whose spectral type has changed from B4 Ia in 1955 to A5 Ia in 1967 to F6 Ia in 1972
w	Watt, a measure of electrical power equal to potential in volts times current in amps.
qed	Quantum Electrodynamics
galactic light	See diffuse galactic light
atmospheric pressure	MICROBURST
ccd	Charged Couple Device
sawtooth wave	A waveform generated electronically (such as the variation of voltage with time), having a uniform increase that regularly and rapidly drops to the initial value
tholus	small domical mountain or hill.
metar	SNOW LEVEL
sidereal period	the period of revolution of a planet around the Sun or a satellite around its primary.
resolving power	(a) The ratio of the mean wavelength of two lines to the minimum resolvable angle
bell's theorem	the theorem that no hidden variables theory satisfying an appropriate locality condition can make statistical predictions in complete agreement with those of quantum mechanics
high-energy particles	Particles of electromagnetic radiation that contain high energies, measured in terms of electron volts
acceleration	The rate of change of velocity with respect to time.
radiated	(adj) A heraldic term used when rays are seen issuing from a charge for example the Madonna radiated as shown below but see ‘radiant’ (also ‘radiating’ and ‘sun-in-splendour’).
time	A measure of the flow of events.
angular houses	The first, fourth, seventh and tenth houses
interloc	A newsletter published mainly for Local Secretaries, reporting on the business of AMC and the national office
absolute	THERMOSPHERE
indian summer	WET BULB DEPRESSION
azimuth	Angular distance in the horizontal plane, measured clockwise from north
average life	see Mean Life [H76]
aurigae	An eclipsing binary with an invisible supergiant companion
coma	An aberration where point sources (stars) at the center of the image are focused to a point but typically appears as "comet-like" radial smudges that get worse towards the edges of the image.
angular size	The angle subtended by an object at a given distance.
conduction band	The unfilled top energy band in a solid
libration orbits	see Lagrangian Points [H76]
horary astrology	Derived from the Latin hora, hour
virtual processes	Quantum-mechanical processes which do not conserve energy and momentum over microscopic timescales, in accordance with Heisenberg's uncertainty principle
apogee	That orbital point farthest from the Earth when the Earth is the center of attraction, as opposed to the Perigee.
crater	A bowl-shaped depression formed by the impact of an asteroid or meteoroid
alfvén number	A dimensionless number characterizing steady fluid flow past an obstacle in a uniform magnetic field parallel to the direction of flow
parallax	The apparent change in position of two objects viewed from different locations.
ellipse	A flattened circle, or oval
counter current	A secondary current setting in a direction opposite to that of the main current.
angular displacement	Symbol: The rotational displacement of an object about an axis
massive habit	This is a large crystal with no definite shape
stochastic cooling	The gathering(i.e., focusing) of clouds of subatomic particles in an accelerator by monitoring their scattering vectors and altering the magnetic environment in an accelerator storage ring to keep them close together
eikonal approximation	An approximation in which the oscillation of a wave front is replaced by the direction of the ray which is normal to the oscillation
nitrogen	Symbol:"N" Atomic Number:"7" Atomic Mass: 14.00amu
niobium	Symbol:"Nb" Atomic Number:"41" Atomic Mass: 92.91amu
a-coefficient	Einstein coefficient, where Aji is the coefficient of spontaneous emission from upper level j to lower level i.
ascending node	The point in the orbit of an object, when it crosses the ecliptic, (or celestial equator) whilst moving south to north
temperature	A measure of the average kinetic energy of the particles of a system
residual intensity	Ratio of correlated flux in the line to correlated flux in the continuum
s-matrix	Scattering Matrix: A matrix representing the transitions from some initial to some final state in a given interaction
prime meridian	the imaginary line of longitude passing from the north pole to the south pole through Greenwich, England
salinity	FRICTION
nom comm	Nominations Committee: responsible for developing a slate of nominees for elected office; may also oversee the election process.
direct motion	Motion that follows the natural order of signs
radiometer	A device that detects radio waves from space and measures their direction
supermultiplet	A multiplet of multiplets
acceleration	Change in velocity (speed, or direction).
critical density	The minimum average density that matter in the universe would need in order for its gravitational pull to slow the universe’s expansion to a halt.
catastrophism	Nineteenth-century hypothesis that depicted the many changes evinced by the geological record as having resulted from cataclysms occurring during a relatively brief period of history
focal length	The distance from the centre of a lens or mirror to its point of focus.
ayanamsa	From the Hindu ayana, the arc that describes the increasing gap between the tropical and sidereal zodiacs
platinum	Symbol:"Pt" Atomic Number:"78" Atomic Mass: 195.08amu
freezing point	MERCURIAL BAROMETER
parallax	The angular difference in apparent direction of an object seen from two different viewpoints.
the bulletin	National Mensa's monthly publication.
pmc	Payload Management Computer, located in the Payload Module, is responsible for command and control of the payload
doppler effect	The apparent change in wavelength of sound or light emitted by an object in relation to an observer's position
iron	Symbol:"Fe" Atomic Number:"26" Atomic Mass: 55.85amu
magnetosphere	Region around an object where the influence of the object's magnetic field can be felt.
velocity	Speed of an object; the change in position over time.
evapotranspiration	PALOUSER
force charge	A property of a particle that determines how it responds to a particular force
abelian group	A mathematical group of transformations with the property that the end result of a series of transformations does not depend on the order in which they are performed
altitude	PRESSURE JUMP
supercell	FLASH FLOOD
orb	The number of degrees by which an aspect may vary from partile (exactness) and remain effective.
geodesy	Measurement and study of the Earth's size and shape
allotropy	The existence of a solid substance in different physical forms
interference pattern	Wave pattern that emerges from the overlap and the intermingling of waves emitted from different locations
descendant	Point opposite the Ascendant and cusp of the seventh house; it describes one's interreation with others.
apparent solar time	The measure of time based on the diurnal motion of the true Sun
light pollution	The degradation of the night sky caused by the combined glow of artificial light, particularly light which is spilled upwards due to poor design
solar arc	The distance the Sun travels from birth position to its secondary progressed position
thermocouple	An instrument used for measuring very small quantities of heat.
rad	Unit of radiation, equal to 100 ergs of ionizing energy absorbed per gram of absorber
comet	A chunk of dirty ice and snow in orbit around the Sun
terminator	The line between day and night on any celestial object.
first canton	A term for that quarter of a flag which occupies the upper hoist - the first quarter, upper hoist or upper hoist canton – see ‘canton 1)' and ‘canton 3)' (also ‘hoist 1)').
space-time foam	Frothy, writhing, tumultuous character of the spacetime fabric on ultramicroscopic scales, according to a conventional point-particle perspective
local sidereal time	The local hour angle of a catalog equinox
inertia	An object's resistance to any change in its motion.
ram	Random Access Memory.
canting	An originally heraldic term for when the design on a shield or banner of arms forms a pun on the name or attributes of the entity or person represented – allusive arms or armes parlantes (see also ‘armorial bearings’).
longitude	TEMPERATE CLIMATE
selectron	The supersymmetric partner of the electron.
ovoid	shaped like an egg
codon	Sequence of three consecutive nucleotides that specifies an amino acid or represents the starting or termination signals of protein synthesis.
occultation	The hiding of one object in the sky by another
zenith	the point directly overhead
gaussian	A random distribution of initial conditions is often referred to as a Gaussian distribution
radiant	the point on the sky from where a shower of meteors appears to come
lightest superpartner	The superpartner with the least mass
cyclonic disturbance	STORM WINDS
bowl	One of the seven horoscope patterns identified by the late Marc Edmund Jones according to the picture formed by planetary distribution in a horoscope
eötvös experiment	(a) An experiment performed in 1909 by the Hungarian physicist Eötvös to establish that the gravitational acceleration of a body does not depend on its composition - i.e., that inertial mass and gravitational mass are exactly equal
gravity	A mutual physical force of nature that causes two bodies to attract each other.
inclination	(a) In astronomy, the angle between one plane and another
telrad	a sighting device for telescopes which projects a bull's-eye on the sky
coulomb force	Electrostatic force between charged particles
semimajor axis	the semimajor axis of an ellipse (e.g
mesohigh	STABLE/STABILITY
supersymmetry	(a) A symmetry relating fermions and bosons
gadolinium	Symbol:"Gd" Atomic Number:"64" Atomic Mass: 157.25amu
h ii region	(a) An area of ionized hydrogen
subsidence	The subsidence is a downward (air) motion
terminal houses	Those houses ruled naturally by water signs: four, eight and twelve
degree	A unit of angular measure (there are 360 degrees in a circle), or a unit of temperature.
light	Electromagnetic radiation with wavelengths of or close to those detectable by the eye
h-magnitude	The magnitude derived from infrared observations at 1.6 microns
asteroid	A rocky or metallic interplanetary body (usually larger than 100 meters in diameter).
vertical flag	See ‘banner 2)'and ‘hanging flag' (also ‘vertically hoisted flag').
scale factor	A measure of changing distances in cosmology
recession	Motion (increasing distance) away
mama	(a) Multi-Anode Microchannel Analyzer
color index	A measure of a star's color, which tells scientists how hot the star's surface is.
natal astrology	The branch of astrology dealing with the individual
drizzle	MIXED LAYER
layered saltire	A term that may be used to describe any saltire where an arm of one colour overlays (or apparently overlays) an arm of a different colour as in the examples given below (see also ‘layered cross’, ‘saltire’ and ‘tripartite').
trigon	The three member signs of a triplicity
metar	SNOW SQUALL
ebs	Electron Bombarded Silicon [LLM96]
launching flags	Those flags flown from a vessel that is being launched prior to fitting out, and which in naval usage are generally (but not invariably) of a prescribed type and sequence (see also ‘dressing lines’ and ‘flag exchange’.
composition	What an object is made of.
iso number	This is the number that indicates the sensitivity (or ‘speed') of a film or a given DSLR exposure.
eclipse	An alignment of two bodies with the observer such that either the nearer body prevents the light from the further body from reaching the observer (strictly speaking, these are occultations), e.g
lorentz invariant	Invariant with respect to Lorentz transformations
snell's law	For a refracted light beam, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant
coplanar	Lying in one plane
coster-kronig transition	An Auger transition in which the vacancy is filled by an electron from a higher subshell of the same shell
lunar return chart	A chart cast for the time the Moon returns to the exact degree, minute, and second it occupied at the moment of an individual's birth.
thallium	Symbol:"Tl" Atomic Number:"81" Atomic Mass: 204.38amu
zenith	The point directly overhead in the sky from an observer's location.
radio stars	Stars with detectable emission at radio wavelengths
firas	Far-Infrared Astronomical Spectrometer [LLM96]
earth	and the center of the
chaos	originally used by the Greeks to describe the limitless void, it is now used to describe unpredictable and apparently random structures
supergravity	(a) A supersymmetric theory of gravity in which the graviton is accompanied by a spin-3/2 particle called the "gravitino"
lunar	month.
channel	In telemetry, one particular measurement to which changing values may be assigned
ero	Extremely Red Object
angstrom	abbreviated Å
sum-over-histories	Probabilistic interpretation of a system's past, in which quantum indeterminacy is taken into account and the history is reconstructed in terms of each possible path and its relative likelihood.
ferromagnet	a material such as iron in which there may be a permanent magnetic moment
anthropic principle	(a) The doctrine that the value of certain fundamental constants of nature can be explained by demonstrating that, were they otherwise, the Universe could not support life and therefore would contain nobody capable of worrying about why they are as they are
aberrations	Effects associated with the performance of optical components which give rise to imperfect optical images
farrum	pancake-like structure
nadir	The point in the celestial sphere directly opposite the zenith; the point directly beneath an observer on Earth; the low point.
illumination	Symbol: E A measure of the visible-radiation energy reaching a surface in unit time
ap	Index of magnetic activity (Planetary Amplitude)
region 10	The region of American Mensa to which CFM belongs
order of magnitude	A factor of ten
bar	A unit of measure of atmospheric pressure
ellipse	A plane curve in which the sum of the distances of each point along its periphery from two points - its "foci" - are equal
solstice	When the Sun reaches its maximum declination
meteoroid	a chunk of space debris
solar constant	(a) Mean radiation received from the Sun at the top level of Earth's atmosphere: 1.95 cal cm-2 min-1
metar	D-VALUE
mural arc	Sixteenth- to nineteenth-century astronomical apparatus comprising a carefully oriented wall on which a calibrated device was fixed, by which the altitudes of celestial objects could be measured
meridian	A great circle, encircling Earth, that passes through the North and South Poles
heterotic string	Gross's version of string theory in which space-times of different dimensions are associated with the same closed loop
accolé	See ‘gorged'.
nutation	A small nodding motion in a rotating body
ftp	File Transfer Protocol (server)
fourier series	A Fourier series decomposes a function into a sum of sines and cosines.
metar	BLOWING SAND
cross	Symbol for matter in casting, or for a physical reference
even-even nuclei	see 4N Nuclei
seaborgium	Symbol:"Sg" Atomic Number:"106" Atomic Mass: (263)amu
gravitational constant	(a) Fundamental constant with units of cm3 g-1 s-2 that determines the gravitational force between two bodies at a given separation
atbd	Algorithm Theoretical Basis Document
officer’s flags	In US usage and in some others, those flags that are flown by the past and present officers of a club, especially of a yacht or boating club – yacht officers flags (but see ‘broad pennant 3)’ and ‘officer's pennants’).
luminous blue variables	LBV -- A variable-star designation for the high-luminosity early type objects
bravais lattice	The Bravais lattice is the basic structure of a crystal
apogee	the outermost point in a terrestrial orbit
solar rotation	Is differential, the equatorial rotation taking less time than the polar by up to 9.4 Earth-days
helium-weak stars	B-type stars in which the helium lines are weaker than in normal stars
irregular galaxy	A type of galaxy with little structure
rna	The molecule that assembles proteins from DNA instructions.
synthesis	The art of combining the various factors revealed in a horoscope and building a balanced judgment of the chart as a whole.
antenna gain	A measure of the directivity of a radio telescope
berkelium	Symbol:"Bk" Atomic Number:"97" Atomic Mass: (247)amu
nomcomm - nominating committee	Person(s) responsible for locating members willing to serve on the ExCom and provide said list of persons to the ExCom and newsletter editor for printing of ballots.
deconvolution	An algorithm-based method for eliminating noise and improving the resolution of digital data
microprocessor	A very large silicon integrated circuit with essentially all the functions of a computer on a single chip
humidity	The amount of water vapour in the air.
gravitino	(a) The fermion partner of the graviton predicted by the supergravity extension of Einstein's theory of general relativity
halo	See ‘nimbus’
hidalgo	Asteroid 944, perhaps 20 km in diameter, with the largest known orbit (a = 5.8 AU), second highest inclination to the ecliptic (42°.5), and second highest eccentricity (e = 0.66) of any known minor planet
a	Spectral type for white stars, such as Sirius, Vega, Altair, Deneb, and Fomalhaut
helium	second element in periodic table, inert gas, known as alpha particle for it nucleus - product of a number of fusion reactions
gum nebula	A giant H II region 30°-40° in diameter in which the Vela pulsar and the Vela X supernova remnant are embedded
theory of cosmological redshifts	The theory that galaxies' redshifts are all due to recessional motion, increase with distance, and thus give an indicator of distance.
segs	Sequence of Events Generation Subsystem.
hpbw	Half Power Beam Width
event horizon	Imaginary surface at the distance from a black hole where the escape velocity is the speed of light
earth	, a few stars shift their position relative to the others when observed year after year
wavelength	the distance between eave crests on any train of electromagnetic radiation; short ones are more energetic than long ones
elliptical orbit	The general shape that describes the motion of one object bound by gravity to another object; a closed figure like a squashed circle.
bandera de guerra	See ‘war flag 1)’ and ‘war flag 2)’.
apparent horizon	On land this is usually an irregular line unless the terrain is level
backscattering	Scattering of radiation (or particles) through angles greater than 90° with respect to the original direction of motion
circinus x-1	A highly variable X-ray source
light pressure	see Radiation Pressure [H76]
mos	Metal Oxide Semiconductor -- A construction used to fabricate microelectronic components
rotation	the spin of a body about its axis.
laser	Light Amplification by Stimulated Emission of Radiation.
ray tracing	Computer simulation of light ray paths through an optical system
speed-of-light circle	see Velocity-of-Light Radius
sun	Our star, the center of our solar system
mare	An area on the moon that appears darker and smoother than its surroundings
chirality	An expression of the basic handedness of nature
internal symmetry	The properties of different elementary particles can be related to each other by mathematical transformations that look very much like the more familiar symmetry properties of our own physical space
sum rule	see f-sum Rule
byte	A group of eight "bits" or binary digits (ones or zeros)
volcano	An opening in the Earth's crust where molten lava, gases and ash are ejected.
indented edge	See ‘scalloped 1)'.
azimuth	The angular distance around the horizon, usually measured from north, through east, of the great circle passing through the object and the zenith.
gaussian year	The period associated with Kepler's third law with a = 1
scuti stars	A group of pulsating variable stars of spectral class A-F with regular periods of 1-3 hours and with small variations in amplitude
crypocrystalline	Rock texture in which individual crystals are too small to be distinguished even using a standard petrographic microscope (less than a few μm in size).
science	(a) Systematic study of Nature, based upon the presumption that the Universe is based upon rationally intelligible principles and that its behavior can therefore be predicted by subjecting observational data to logical analysis
elliptical galaxy	A galaxy whose structure shaped like an ellipse and is smooth and lacks complex structures such as spiral arms.
finder	a small, wide-field telescope attached to a larger telescope
tidal heating	frictional heating of a satellite's interior due to flexure caused by the gravitational pull of its parent planet and possibly neighboring satellites.
sc	Steering Committee.
residual current	The observed current minus the astronomical tidal current or the mean current without periodic components.
quark jet	Because quarks must end up in hadrons, quarks that are produced in collisions actually appear in detectors as a narrow jet of hadrons, mostly pions
trough	RIME
astronomical color index	Difference in a star's brightness when measured on two selected wavelengths, in order to determine the star's temperature
flat universe	(a) A Universe in which there is no curvature to the spacetime continuum
chromosphere	the layer of the solar atmosphere that is located above the photosphere and beneath the transition region and the corona
surface brightness	This is a measure of how bright something is (like a galaxy or a nebula) for each unit of area (a square arc-second).
swell	CALORIE
hestia	Unofficial name for Jupiter VI
sankrânti	The sun's entry into one of 27 or 28 sections into which the ecliptic is divided for Indian calendars
liquid crystal	substances intermediate in their properties between liquids and crystals
easy aspect	See harmonious aspects.
obliquity	the angle between a body's equatorial plane and orbital plane.
m-type	Having a spectral type of M, that is, red like Betelgeuse and Antares
a-type	Having a stellar spectral type of A, that is, hot and white, like Sirius and Vega
hot big bang	Later, but fundamental, concept within the big-bang theory, that the primordial explosion occurred in terms of almost unimaginable heat
fluctuations	(a) Spontaneous deviations of the macroscopic variables from a certain `reference' state, arising from the thermal motion and the interactions of the molecules
quarter-moon	See ‘crescent 1)'.
scintillation	(a) In radio astronomy, a rapid oscillation in the detected intensity of radiation emitted by stellar radio sources, caused by disturbances in ionized gas at some point between the source and the Earth's surface (usually in the Earth's own upper atmosphere)
celestial equator	The red line running horizontally across the center of the Equatorial Sky Chart represents the Celestial Equator
internet	A global spider-web-like network of computers and computer systems with no central hub or single point of control
potentially hazardous asteroids	PHAs are currently defined based on parameters that measure the asteroid's potential to make threatening close approaches to the Earth
flat antenna	A flat antenna is the most compact type of satellite dish
superstring theory	(a) A version of string theory which incorporates the ideas of supersymmetry
critical exponent	near a critical region one physical quantity, such as the magnetisation
eleven-dimensional supergravity	Promising higher-dimensional supergravity theory developed in the 1970s, subsequently ignored, and more recently shown to be an important part of string theory
extinction	(a) Attenuation of starlight due to absorption and scattering by Earth's atmosphere, or by interstellar dust
astronomical twilight	The period from sunset to the time that the Sun is 18° below the horizon; or the corresponding period before sunrise
gegenschein	a round or elongated spot of light in the sky at a point 180 degrees from the Sun
arcsecond	1/60 of an arminute or 1/3600 of a degree, designated by the symbol ".
ultraviolet	the region of the electromagnetic spectrum that falls outside of the visible, just beyond violet
compact radio source	A radio source which has a small angular extent and is strongest at shorter wavelengths (cf
chasma	canyon.
gegenschein	a round or elongated spot of light in the sky at a point 180 degrees from the sun; also called counter glow
cerenkov radiation	(a) A bluish light that is emitted when charged particles travel through a transparent medium at a speed that exceeds the speed of light in the medium
silicon	Symbol:"Si" Atomic Number:"14" Atomic Mass: 28.09amu
surface boundary layer	See atmospheric boundary layer.
hamiltonian theory	A theory for calculating the trajectory of a particle under an applied force
storm	WEATHER VANE
isotropic	The same in all directions.
cantabrian labarum	The flag of the Cantabrian independence movement showing a wheel-like emblem that is considered symbolic of the ancient Cantabrians of Northern Spain.
imum coeli	From the Latin, literally bottom of the heavens; the zodiacal point opposite the Medium Coeli (Midheaven, MC)
dawn	NIMBOSTRATUS
saturated	DIABLO WINDS
aspect	The angular distance, calculated in specific number of degrees of the chart wheel, between two celestial points or planets
cross-spectrum	The transform of the covariance spectrum
megaflops	Millions of floating-point operations per second
isolated m	A newsletter for Mensans who can't or choose not to participate in local group activities, because of geographic isolation or for other reasons.
anabatic wind	KATAFRONT
individual houses	Houses one, five and nine, all ruled by natural fire signs
natacadpr	RASC-AL (Revolutionary Aerospace Systems Concepts Academic Linkage): 2002 Advanced Concept Design Presentation
cti	Charge Transfer Inefficiency
peak ring	a central uplift characterized by a ring of peaks rather than a single peak; peak rings are typical of larger terrestrial craters above about 50 kilometers (30 miles) in diameter.
radio source counts	The integral number of radio sources per unit solid angle whose measured flux density at the operating frequency of a radio telescope exceeds a certain given value; plot of log N (number of sources) versus log S (where S is in flux units)
minute of arc	A unit of angle equal to 1/60 of a degree
general precession	The sum of the lunisolar and the planetary precession(q.v.)
eccentricity	The measure of how an object's orbit differs from a perfect circle
cephied	A class of yellow giant or supergiant, pulsating variable star used to measure cosmological distances, e.g
radial velocity	The velocity component along the line of sight toward or away from an observer
idl	Interactive Data Language
astatine	A radioactive element belonging to the halogen group
goldstone boson	A massless spin-0 particle which arises whenever a (continuous) global symmetry is spontaneously broken
orbital eccentricity	Eccentricity is a measure of how an orbit deviates from circular
galactic latitude	Angular distance around the galactic equator from the galaxy's center.
ym	Young Mensan under the age of 18
charm	(a) The fourth flavor (i.e
cosmic substratum	An idealised, smooth cosmic fluid which is spread throughout space evenly and thus possesses a constant density
enstatite	a type of primitive chondrite
caliche	Calcium carbonite, CaCO3, that often encrusts meteorites found in desert areas covered Caliche forms naturally during repeated wetting and drying in arid climates where calcium is present in the soil.
unit colour	See ‘colour 2)’ and ‘colours 2)'.
conifold transition	Evolution of the Calabi-Yau portion of space in which its fabric rips and repairs itself, yet with mild and acceptable physical consequences in the context of string theory
ombudsman	A troubleshooter who listens to gripes, settles complaints, and generally pours oil on troubled waters.
thunderstorm	APHELION
blaauw mechanism	A mechanism advanced to explain the disruption of a binary system by the decrease in the gravitational binding force when an ejected shell overtakes the secondary component
subspace	a subset of a vector space which is closed under the operations of vector addition and scalar multiplication
surface brightness	The measure of the amount of light that an object, especially a galaxy, emits per area of the sky
spectral classification	Commonly, the system devised by Annie Cannon combining the perceived colour of a star with its spectral characteristics
inclination	measure of the tilt of a planet's orbital plane, in relation to that of the Earth
saint george's canton	See ‘canton of St
luminous intensity	Symbol: Iv The luminous flux from a point source per unit solid angle
equinox	A time of equal day and equal night occuring twice a year at the beginning of Spring and Autumn.
collinear	Three or more points lying in a straight line
bib	Blocked Impurity Band
earth	-size "pimples" to swollen scars halfway across the surface
earth	's sky, instead of relative to the background stars
bond albedo	Fraction of the total incident light reflected by a spherical body
palewise	See ‘in pale’.
conjunction	The alignment of an two astronomical objects along the same line toward the sun
heliocentric theory	Odin was the king of the gods...
convergence	GRAUPEL
median	Literally the middle value in a sequence of values arranged in increasing size order
iridium flare	A bright flash in the night sky caused by sunlight glinting off solar panels of Iridium communications satellites
baud	The baud is a unit of telegraph signalling speed; one baud is equal to one pulse per second
zulfikar	A term for the split-bladed or double-pointed "Sword of Ali" (originally a symbol of - the Janissaries - an elite military formation of the Ottoman Empire) that has appeared on several Arab flags (see also ‘shahada' and ‘takbir').
kent vane-fly	See ‘bob’.
brackett series	The spectral series associated with the fourth energy level of the hydrogen atom
evaporation	CONDENSATION FUNNEL
mass models	Models that attempt to infer the distribution of mass in an astronomical system by comparing the observed properties of the system (such as the distribution of light) with those properties predicted by various theoretical distributions of mass
conservative scattering	Scattering that occurs in the absence of absorption
kaon	A type of meson
dew point	ISOHEL
rayleigh-jeans limit	An approximation valid at sufficiently long wavelengths (longward of the peak intensity) to the energy distribution of a blackbody
animoder of tetrabiblos	A method of birth time rectification, now obsolete, presented by Ptolemy
orbit	the path of an object that is moving around a second object or point.
daylight saving time	The practice of advaning the clock one hour in the spring of the year
lyrae	see Vega [H76]
house	One of the twelve mathematically derived sections (houses) of a horoscope, each of which represents a particular area of life
aircraft marking	In UK and some other usage, a collective term for the markings of nationality and identification on the wings, fuselage and tail plane/fin of primarily (but not exclusively) military aircraft – but see ‘fin flash' and ‘roundel 1)' (also ‘aircraft insignia' above, ‘fuselage markings 1)' and ‘wing marking(s) 1))').
superfluidity	A phenomenon occurring in liquid helium-4 below about 2.17 degrees, in which the liquid flows through thin capillaries without apparent friction and displays many other anomalous properties
equator	COROMELL
constellation	A grouping of stars which many times form a shape or pattern.
penumbra	the area of partial illumination surrounding the darkest part of a shadow caused by an eclipse.
steroid	Steroids are lipids that are based on the cholesterol molecule
electron	A negatively charge elementary particle that typically resides outside the nucleus of an atom but is bound to it by electromagnetic forces
light year	The distance travelled by light, through space, in one year
transparent	Able to pass radiation without significant deviation or absorption
infinity	Space, time or a quantity which has no bounds and goes on forever.
calcite compensation depth	The calcite compensation depth (CCD) is the depth at which the input of calcite from sedimentation exactly balances the dissolution at the top of the sediments
binoculars	Two small telescopes put next to each other so that both eyes can look at an object at the same time.
hidden mass	Matter whose presence is inferred from dynamical measurements but which has no optical counterpart
key words	Words that encapsulate the meaning of an astrological factor
curvature of space-time	The property that the geometry of space and time becomes curved and distorted in the presence of strong gravitational fields, so that the usual laws of geometry cannot apply.
general relativity	(a) Specific theory of gravitation in terms of curved space-time developed by Einstein; provides field equations to determine the space-time metric for a given distribution of matter
line wings	Broad "wings" that appear on either side of a spectral line when the number of atoms producing the line is very great
argument of the pericentre	The angle, measured around the orbital plane, between the ascending node and the pericentre.
harvard classification	See Henry Draper system.
galaxy interactions	In regions of the universe that are denser than average, the interactions of galaxies at a distance by the force of gravity
magnetic field	A condition found in the region around a magnet or an electric current, characterized by the existence of a detectable magnetic force at every point in the region and by the existence of magnetic poles.
jupiter	The king of the gods, a planet symbolising matters to do with the law, religion, authority, the higher mind and so on
eccentric anomaly	In undisturbed elliptic motion, the angle measured at the center of the ellipse from pericenter to the point on the circumscribing auxiliary circle from which a perpendicular to the major axis would intersect the orbiting body
chapman-jouguet detonation	A detonation in which the velocity of the shock front with respect to the material behind it is equal to the corresponding sound velocity
zeropoint	The magnitude corresponding to one data number per second from the array detector for a star of zero color term (like Vega) corrected for absorption in the Earth's atmosphere
wedge wavy	See ‘piles(s) wavy 1)’.
heat	A form of energy that can be transferred from one place or object to another when there is a difference in temperature.
tassels	A decoration of twisted fabric or metal, often surrounding a wooden core and hanging from a cord, attached to a staff or directly onto a flag – especially a colour or parade flag (see also ‘colour 2)’, ‘cord(s) 1)’, ‘lanyard 1)’ and ‘parade flag 2)’).
radon	Symbol:"Rn" Atomic Number:"86" Atomic Mass: (222)amu
rayleigh-taylor instability	A type of hydrodynamic instability for static fluids (see Taylor instability) in which the density increases outward [H76]
laminar flow	Steady flow in which the fluid moves past a surface in parallel layers of different velocities
epoch	or era, a point of time on which the counting of days, months, and years of calendar starts
kalends	name of the first day of a month of the
hubble diagram	Plot of galaxy redsifts against their distances
tidal wave	The wave motion of the tides
iraf	Image Reduction and Analysis Facility
rulership	Different signs are "ruled" by different planets and their influences can be affected by this fact.
bright ring	see Saturn's rings
maxwell distribution	(a) An expression for the statistical distribution of velocities among the molecules of a gas at a given temperature
sulfur	Symbol:"S" Atomic Number:"16" Atomic Mass: 32.06amu
hold-time	The time taken to use up all the liquid cryogens, like LN2, in a cooled CCD cryostat
diameter	The distance from one side of a circle or sphere to the point opposite, passing through the centre.
molecular cloud	an interstellar cloud of molecular hydrogen containing trace amounts of other molecules such as carbon monoxide and ammonia.
race	Swiftly flowing water in a narrow channel or river; also the channel itself which may be artificial as in a mill-race
focal reducer	An optical component or system for changing the image scale of a telescope to achieve a better match between the seeing disk and the pixel size
smooth space	A spatial region in which the fabric of space is flat or gently curved, with no pinches, ruptures, or creases of any kind
sss	Sea surface salinity
roshydromet	Russian Federal Service for Hydrometeorology and Environment Monitoring
takbir	A term for the Arabic inscription Allahu Akbar or “God is Great” that has appeared on several Arab Flags and can currently be seen on those of Iran and Iraq (see also ‘shahada’ and ‘zulficar’).
mulliken bands	Spectral bands of the C2 radical
season	summer autumn, winter, spring
fixed signs	Taurus, Leo, Scorpio and Aquarius, which are related to a fixed or stable mode of expression
hypercharge	Twice the charge of a charge multiplet (q.v.)
electron collider	Short for electron-positron collider
assurbanipal	(669-625 B.C.) King of Assyria
orbit	The elliptical path of an object that is gravitationally bound to another object.
cn-weak stars	High-velocity star with both weak metallic lines and weak CN bands
isothermal change	A process that takes place at constant temperature
orbit	An orbit is a closed path that an object takes as it revolves around another body
invariant plane	The plane defined by the total angular momentum of the solar system
strangeness	(a) A property of hadrons which may have a zero or non-zero value, depending on their rate of decay
winding energy	The energy embodied by a string wound around a circular dimension of space
dna	A long, replicating molecule, shaped like a twisted ladder, that is the basis of the genetic code
charles' law	A scientist named Jacques Charles did many experiments involving gas volumes and temperatures
ag	Annual Gathering: American Mensa’s annual convention meets during the summer months in a different host city each year.
fixed point	A scale-invariant limit point of the flow of configurations or coupling constants generated by a coarse-graining operation
maxwell-boltzmann distribution	The distribution function that any species of particle will have if it is in thermodynamic equilibrium
altitude	The angular distance from the observer's horizon, usually taken to be that horizon that is unobstructed by natural or artificial features (such as mountains or buildings), measured directly up from the horizon toward the zenith; positive numbers indicate values of altitude above the horizon, and negative numbers indicate below the horizon --- with negative numbers usually being used in terms of how far below the horizon the sun is situated at a given time [for example, the boundary between civil twilight and nautical twilight is when the sun is at altitude -6 degrees].
key cycle	Sidney K
planet	Scarp A line of cliffs produced erosion or by the action of faults.
accretion	(a) Collection of material together, generally to form a single body
adiabatic demagnetization	A method of producing temperatures close to absolute zero
lutetium	Symbol:"Lu" Atomic Number:"71" Atomic Mass: 174.97amu
geneva convention flag	See 'safe conduct flag 1)'.
string	(a) Fundamental one-dimensional object that is the essential ingredient in string theory
solid-state	Usually implies crystalline semiconductor materials used in the electronics industry
perihelion	Point in orbit closest to Sun. (Greek: peri (near) Helios (Sun))
enthalphy	The heat content of a body
calibration	Calibration is the adjustment of the numerical or physical parameters in a model to improve the agreement between the results of the model and observations.
spectrum	the colors you see when white light is split apart
significant figures	The number of digits known for certain in a quantity.
cso	CalTech Submillimeter Observatory [LLM96]
background noise	All the interference effects in a system which is producing, measuring, or recording a signal
cu	The chemical symbol for copper
fission chain reaction	Nuclear power plants use nuclear reactors to produce electricity
antenna temperature	A term used to describe the strength of a signal received from a radio source
respiration rate	The number of breaths a person makes per minute.
spherical aberration	This is an error in some lenses (and mirrors) that causes light rays coming from the edge of the lens to be brought into focus at a different point to those rays that are passing through the lens's centre
department pennant	See ‘service pennant’.
doppler effect	(Christian Doppler 1803-1853) the apparent change in wavelength of sound or light caused by the motion of the source, observer or both
winter solstice	The moment when the Sun reaches its greatest distance south of the celestial equator, on or about December 22
energy	(1) The capacity to do work
axis	also known as the poles, this is an imaginary line through the center of rotation of an object.
cbr	Cosmic Background Radiation [HH98]
spectroscope	an instrument that breaks up white light from a star into its different colors
range of tide	The difference in height between consecutive high and low tides at a place
multi-dimensional hole	A generalization of the hole found in a doughnut to higher-dimensional versions
radio	Electromagnetic radiation with the lowest energy and longest wavelength
calibi-yau space	These six-dimensional spaces are hypothesized as arising when the ten dimensions of superstring theory are compactified down to four dimensions
converging mirror	(Converging Reflector) A mirror that can reflect a parallel beam into a convergent beam
electrovalent bond	A chemical bond that occurs between two atoms when one or more electrons are passed from one atom to another
cassegrain focus	An optical arrangement in which light rays striking the parabolic concave primary mirror of a reflecting telescope are reflected to the hyperbolic convex secondary mirror, and re-reflected through a hole bored in the primary to a focus behind it
'f' cross	See ‘one-and-a-half armed cross’.
igdds	Integrated Global Data Dissemination Service
cold-gas approximation	In MHD studies: An approximation in which the sound speed is much less than the Alfvén speed or the gas pressure is much less than the magnetic pressure
fifo	First-In-First-Out buffer
isomer	An isomer is a molecule or compound that has the same number of atoms as another but a different structure
calcium	Symbol:"Ca" Atomic Number:"20" Atomic Mass: 40.06amu
velocity	A vector that denotes both the speed and direction a body is moving.
absolute brightness	Any measure of the intrinsic brightness or luminosity of a celestial object.
angle	The opening between two straight lines that meet at a point.
cpt invariance	A symmetry which is believed to hold true for all particles throughout the course of universal history
handbook and directory	The IEM Handbook and Member Directory is published at the discretion of the Exceutive Board and is available in hard copy or .pdf format to current members only
fresnel lens	A type of lens with one surface cut in steps so that transmitted light is refracted just as if by a much thicker (and heavier and more expensive) conventional lens
orbit	the path followed by any celestial object moving under the control of another's gravity
cause of the seasons	The tilt (obliquity) of the Earth's axis to its orbit plane causes first the North Pole and later the South Pole to be tipped toward the Sun during the course of a year.
earth system	The Earth system can be divided in five spheres: the atmosphere (gaseous envelope), the hydrosphere (liquid water), the cryosphere (solid water, i.e
bev	One billion (109) electron volts
geologist	A geologist is a scientist who studies geology.
e line	A Fraunhofer line at 5270 Å
big bang	According to the 'standard' cosmological model, a simultaneous explosion throughout space that is at the origin of our universe.
ejecta	Material from beneath the surface of a body such as a moon or planet that is ejected by an impact such as a meteor and distributed around the surface
maximum entropy method	MEM: An image reconstruction methodology which defines a measure of information content and seeks to maximize it
smatter	The superpartners of the Standard Model particles
gene	The minimum amount of genetic material that expresses a characteristic of living organism; a sequence of several hundred bases along DNA molecule.
bracketing	Bracketing is an imaging method where you take several exposures (of the same object) with slightly different settings either side of the planned settings, to see what works best.
faculae	the bright patches on the sun's photosphere
declination	Arc of a meridian between a point on the surface and the point on the equator.
queen's colour	See ‘colour 2)' and ‘colours 2)'.
magnetic pole	Either of two limited regions in a magnet at which the magnet's field is most intense.
closed string	A type of string that is in the shape of a loop
stratosphere	Region of the atmosphere between the troposphere and the mesosphere, at an approximate altitude of 12 to 50 kilometers.
californium	Symbol:"Cf" Atomic Number:"98" Atomic Mass: (251)amu
virtual phase	A type of CCD in which only one electrode is physically outside the silicon and is such as to obscure only half of the pixel
inverse square law	The relation describing any entity, such as radiation or gravity, that varies as 1/r^2, where r is the distance of the entity from the source.
-- theory	Explanation of the big-bang theory in terms of nuclear physics, proposed by Ralph Alpher, Hans Bethe and George Gamow in 1948; it was later slightly corrected by Chushiro Hayashi
escape velocity from earth	11.2 km/s; Mach 34.
sunspot number	(a) (Also called the Wolf Number or Relative Number.) A quantity (devised by R
cosmic time	A time coordinate that can be defined for all frames in a homogeneous metric, representing the proper time of observers at rest with respect to the Hubble flow
constellation	A pattern of stars in the sky that humans think look like some familiar shape
stony iron	a meteorite which contains regions resembling both a stone meteorite and an iron meteorite.
severe weather	LITHOMETEOR
cern	(a) The European Laboratory for Particle Physics (formerly the Conseil Europeen pour la Recherche Nucleaire ), located near Geneva in Switzerland
astrometric ephemeris	An ephemeris of a Solar-System body in which the tabulated positions are essentially comparable to catalog mean places of stars at a standard epoch
union mark	A symbol expressing the unification of two or more territories - such as the British Union Jack or the former Norwegian-Swedish Union Mark - either employed alone or as a charge on a flag (see also ‘charge’, ‘conjoined’, ‘interlaced’, ‘union’, ‘union flag’ and ‘union jack’ above).
dioptre	(also diopter) A measure of the refractive power of a lens
evolution	(a) In Biology the theory that coniplex and multifarious living things developed from generally simpler and less various organisms
equinox	The two points at which the Sun crosses the celestial equator in its yearly path in the sky
correlator	In radio astronomy, an instrument which measures the similarity between the current fluctuations due to shot noise (q
strongly coupled	Theory whose string coupling constant is larger than 1
sea ice	Sea ice is the ice that forms when seawater freezes
hilbert space	A mathematical tool used in the formalism of quantum mechanics
gpcp	Global Precipitation Climatology Project
riemannian geometry	A large class of non-Euclidean geometries
chain silicates	Minerals composed of chains of silicon tetrahedra
balanced equation	A balanced chemical equation has equal numbers of atoms on each side of the equation
queue fourché	See ‘double queued'.
charge	Describes an object's ability to repel or attract other objects
closed universe	A geometric model of the universe in which the overall structure of the universe closes upon itself like the surface of a sphere
statistic	A statistic is the result of applying a statistical algorithm to some data
raster	The area of an oscilloscope upon which the image is produced
contour integral	A powerful mathematical tool used in complex geometry whereby the value of an integral is determined by drawing a contour or boundary and evaluating singularities, poles, and residues inside
refraction	The deflection or bending of electromagnetic waves when they pass from one kind of transparent medium into another.
relativistic	Approaching the velocity of light
hac	Hydrogenated Amorphous Carbon
fu	Flux Unit [LLM96]
redshift-distance relation	The correlation between redshift in the spectra of galaxies and their distances
kinetic energy	The amount of energy an object has due only to its velocity.
fall ellipse	The location of a number of meteorite fragments from a single fall will spread out over an area in the shape of an ellipse
equinox	Literally meaning "equal night (as day)." Either of the two points (vernal, autumnal) on the celestial sphere where the ecliptic (which is the apparent path of the sun on the sky) intersects the celestial equator
weakly coupled	Theory whose string coupling coyistant is less than 1
velocity	The speed and the direction of an object's motion
bel	A number used mainly in English-speaking countries to express the ratio of two powers as a logarithm to the base ten
radio interferometer	Type of radio telescope that relies on the use of two or more aerials at a distance from each other to provide a combination of signals from one source which can be analyzed by computer
radiant	(a) The point in the sky from which a meteor shower appears to emanate
subastral point	When used to solve a celestial observation, either the celestial or terrestrial triangle may be called the astronomical triangle.
solar cycle	The 11-year period over which the activity of the Sun increases and decreases; phenomena such as sunspots and solar flares are most common during a time of peak activity, called a solar maximum, but may be absent entirely when activity is at a low ebb, a solar minimum.
hirayama families	Groups of minor planets with similar orbital elements
magnitude	A measure of a star's brightness
bound-free transitions	Transitions in which a bound electron in any energy level is liberated
velocity	A vector quantity equal to speed in a given direction
schottky barrier	A metal to semiconductor interface without any insulation layer produces an energy barrier in the semiconductor which can be used like a diode
birefringent crystal	A crystal that splits incident transmitted light into two beams, each polarized perpendicularly to the other
carbon asteroid	Dim asteroids which are located near the outer regions of the asteroid belt
elliptical galaxy	A common type of galaxy that has the shape of an ellipsoid (similar to a globe compressed in one or more dimensions)
interstellar space	The dark regions of space located between the stars.
minkowski metric	form of the metric that is valid in an inertial frame; underlying geometry of special relativity
amphidromic point	A no-tide point, from which cotidal lines radiate.
labes	landslide.
electron	(a) Negatively charged fundamental particle (also called a beta particle) found in the atoms of all elements, where it "orbits" (at different energy levels and with different directions of spin) round the central nucleus
altitude	angle in degrees above the horizon.
c stars	A class of carbon stars ( q.v.), defined by Morgan and Keenan to replace the Harvard R and N spectral classes
electromagnetic spectrum	The full range of electromagnetic radiation from long to short wavelengths, or low to high frequencies
bethe-weizsäcker cycle	(a) See proton-proton cycle
vocational astrology	That branch of astrology devoted to career counseling in terms of the aptitudes and needs shown in the natal horoscope.
magnetic field	the field responsible for magnetic forces, now incorporated along with the electric field, into the electromagnetic field
double asteroid	two asteroids that revolve around each other and are held together by the gravity between them
rampant	See ‘Appendix V’.
geology	Scientific study of the dynamics and history of the earth, as evidenced in its rocks, chemicals, and fossils
linea	elongate marking.
tornadoes	WARM
skew t-log p diagram	VIRGA
density	The ratio of the mass of an object to its volume
pythagoras	Greek 569-470 B.C., studied in Egypt
ephemeris time	(a) Time based on the ephemeris second
stellar halo	see Halo [C95]
full	a phase of the Moon or other planetary object when it is completely illuminated as seen by the observer; occurs when the object is at opposition
vernal	From the Latin vernus, belonging to spring; of or pertaining to spring.
aperture	The size of the primary optical surface of an astronomical instrument (telescope), usually given in inches, centimeters, or meters
stellar evolution	(a) How a star changes with time
hunter's moon	See Figure 1512.
radio observatory	Any system which makes astronomical observations at radio wavelengths, generally requiring an antenna, receiver, and observer/data recorder.
color-color plot	Traditionally, a plot of B - V versus U - B
vergette	See ‘paly’ in Appendix VI.
hubble law	(a) The law that recessional speed is proportional to distance for a homogeneous and isotropic universe
transducer	Device for changing one kind of energy into another, typically from heat, position, or pressure into a varying electrical voltage or vice-versa, such as a microphone or speaker.
metric system	A system of measurement based on powers of ten, with fundamental units of kilograms for mass, meters for length, and seconds for time.
holtsmark approximation	An approximation in which the lines emitted and absorbed by atoms are subject to the fluctuating electrostatic fields to which the atom is subject in an ionized atmosphere
white light	visible light that includes all colors and, therefore, all visible wavelengths.
unicolour/unicoloured	See ‘monocolour’.
chromosphere	the lower level of the solar atmosphere between the photosphere and the corona
aphelion	the point of a planet's orbit where distance from the sun is greatest
neodymium	Symbol:"Nd" Atomic Number:"60" Atomic Mass: 144.24amu