User:Conrad.Irwin/nasa


 * create aberration (aberration)
 * create aberration constant (aberration constant)
 * create ablate (ablate)
 * create ablating material (ablating material)
 * create ablating nose cone (ablating nose cone)
 * create ablation (ablation)
 * create ablatively (ablatively)
 * create ablative material (ablative material)
 * create ablator (ablator)
 * create abort (abort)
 * create Abridged Nautical Almanac (Abridged Nautical Almanac)
 * create absolute (absolute)
 * create absolute altimeter (absolute altimeter)
 * create absolute altitude (absolute altitude)
 * create absolute coordinate system (absolute coordinate system)
 * create absolute delay (absolute delay)
 * create absolute humidity (absolute humidity)
 * create absolute index of refraction (absolute index of refraction)
 * create absolute instrument (absolute instrument)
 * create absolute magnitude (absolute magnitude)
 * create absolute manometer (absolute manometer)
 * create absolute motion (absolute motion)
 * create absolute pressure (absolute pressure)
 * create absolute refractive index (absolute refractive index)
 * create absolute system of units (absolute system of units)
 * create absolute temperature (absolute temperature)
 * create absolute temperature scale (absolute temperature scale)
 * create absolute vacuum (absolute vacuum)
 * create absolute vorticity (absolute vorticity)
 * create absolute zero (absolute zero)
 * create absorptance (absorptance)
 * create absorption (absorption)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=absorption%20band&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20A%20range%20of%20wavelengths%20%28or%20frequencies%29%20in%20the%20%5B%5Belectromagnetic%20spectrum%5D%5D%20within%20which%20radiant%20energy%20is%20absorbed%20by%20a%20substance.%20See%20%5B%5Babsorption%20spectrum%5D%5D.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AWhen%20the%20absorbing%20substance%20is%20a%20polyatomic%20gas%2C%20an%20absorption%20band%20actually%20is%20composed%20of%20a%20group%20of%20discrete%20absorption%20lines%20which%20appear%20to%20overlap.%20Each%20line%20is%20associated%20with%20a%20particular%20mode%20of%20vibration%20or%20rotation%20induced%20in%20a%20gas%20molecule%20by%20the%20incident%20radiation.%3Cbr/%3E%20The%20absorption%20bands%20of%20oxygen%20and%20ozone%20are%20often%20referred%20to%20in%20the%20literature%20of%20atmospheric%20physics.%20%3Cbr/%3EThe%20important%20bands%20for%20oxygen%20are%3A%20%28a%29%20the%20Hopfield%20bands%2C%20very%20strong%2C%20between%20about%20670%20and%201000%20angstroms%20in%20the%20ultraviolet%3B%20%28b%29%20a%20diffuse%20system%20between%201019%20and%201300%20angstroms%3B%20%28c%29%20the%20Schumann-Runge%20continuum%2C%20very%20strong%2C%20between%201350%20and%201760%20angstroms%3B%20%28d%29%20the%20Schumann-Runge%20bands%20between%201760%20and%201926%20angstroms%3B%20%28e%29%20the%20Herzberg%20bands%20between%202400%20and%202600%20angstroms%3B%20%28f%29%20the%20atmospheric%20bands%20between%205380%20and%207710%20angstroms%20in%20the%20visible%20spectrum%3B%20and%20%28g%29%20a%20system%20in%20the%20infrared%20at%20about%201%20micron.%3Cbr/%3E%20The%20important%20bands%20for%20ozone%20are%3A%20%28a%29%20the%20Hartley%20bands%20between%202000%20and%203000%20angstroms%20in%20the%20ultraviolet%2C%20with%20a%20very%20intense%20maximum%20absorption%20at%202550%20angstroms%3B%20%28b%29%20the%20Huggins%20bands%2C%20weak%20absorption%20between%203200%20and%203600%20angstroms%3B%20%28c%29%20the%20Chappius%20bands%2C%20a%20weak%20diffuse%20system%20between%204500%20and%206500%20angstroms%20in%20the%20visible%20spectrum%3B%20and%20%28d%29%20the%20infrared%20bands%20centered%20at%204.7%2C%209.6%20and%2014.1%20microns%2C%20the%20latter%20being%20the%20most%20intense.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create absorption band] (absorption band)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=absorption%20coefficient&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20A%20measure%20of%20the%20amount%20of%20normally%20incident%20%5B%5Bradiant%20energy%5D%5D%20absorbed%20through%20a%20unit%20distance%20or%20by%20a%20unit%20mass%20of%20absorbing%20medium.%20Compare%20%5B%5Btransmission%20coefficient%5D%5D.%0A%23%20In%20%5B%5Bacoustics%5D%5D%2C%20the%20ratio%20of%20the%20sound%20energy%20absorbed%20by%20a%20surface%20of%20a%20medium%20%28or%20material%29%20exposed%20to%20a%20sound%20field%20or%20sound%20radiation%20to%20the%20sound%20energy%20incident%20on%20the%20surface.%20The%20stated%20values%20of%20this%20ratio%20are%20to%20hold%20for%20an%20infinite%20area%20of%20the%20surface.%20The%20conditions%20under%20which%20measurements%20of%20absorption%20coefficients%20are%20made%20are%20to%20be%20stated%20explicitly.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AThree%20types%20of%20absorption%20coefficients%20associated%20with%20three%20methods%20of%20measurement%20are%3A%20chamber%20absorption%20coefficient%2C%20obtained%20in%20a%20certain%20reverberation%20chamber%3B%20free-wave%20absorption%20coefficient%2C%20obtained%20when%20a%20plane%2C%20progressive%2C%20sound%20wave%20is%20incident%20on%20the%20surface%20of%20the%20medium%3B%20sabine%20absorption%20coefficient%2C%20obtained%20when%20the%20sound%20is%20incident%20from%20all%20directions%20on%20the%20sample.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create absorption coefficient] (absorption coefficient)
 * create absorption cross section (absorption cross section)
 * create absorption-emission pyrometer (absorption-emission pyrometer)
 * create absorption factor (absorption factor)
 * create absorption line (absorption line)
 * create absorption spectrum (absorption spectrum)
 * create absorptive index (absorptive index)
 * create absorptive power (absorptive power)
 * create absorptivity (absorptivity)
 * create absorptivity-emissivity ratio (absorptivity-emissivity ratio)
 * create acceleration (acceleration)
 * create acceleration of gravity (acceleration of gravity)
 * create accelerator (accelerator)
 * create accelerometer (accelerometer)
 * create acceptor (acceptor)
 * create accidental error (accidental error)
 * create acclimatization (acclimatization)
 * create accommodation coefficient (accommodation coefficient)
 * create accumulator (accumulator)
 * create accustomization (accustomization)
 * create aclinic line (aclinic line)
 * create acoustic (acoustic)
 * create acoustic delay line (acoustic delay line)
 * create acoustic description (acoustic description)
 * create acoustic excitation (acoustic excitation)
 * create acoustic generator (acoustic generator)
 * create acoustic Mach meter (acoustic Mach meter)
 * create acoustic radiation pressure (acoustic radiation pressure)
 * create acoustic refraction (acoustic refraction)
 * create acoustics (acoustics)
 * create acoustic streaming (acoustic streaming)
 * create acoustic velocity (acoustic velocity)
 * create acoustic vibration (acoustic vibration)
 * create acoustic wave (acoustic wave)
 * create acquisition (acquisition)
 * create acquisition and tracking radar (acquisition and tracking radar)
 * create actinic (actinic)
 * create actinic balance (actinic balance)
 * create actinogram (actinogram)
 * create actinograph (actinograph)
 * create actinometer (actinometer)
 * create actinometry (actinometry)
 * create active (active)
 * create active element (active element)
 * create active homing (active homing)
 * create active homing guidance (active homing guidance)
 * create active leg (active leg)
 * create active satellite (active satellite)
 * create active tracking system (active tracking system)
 * create active transducer (active transducer)
 * create actuating system (actuating system)
 * create adaptation (adaptation)
 * create adaptation brightness (adaptation brightness)
 * create adaptation illuminance (adaptation illuminance)
 * create adaptation level (adaptation level)
 * create adaptation luminance (adaptation luminance)
 * create adapter (adapter)
 * create adapter skirt (adapter skirt)
 * create adaptive control system (adaptive control system)
 * create ADC (ADC)
 * create Adcock antenna (Adcock antenna)
 * create adder (adder)
 * create additional apparent mass (additional apparent mass)
 * create additive (additive)
 * create address (address)
 * create ADF (ADF)
 * create adiabat (adiabat)
 * create adiabatic (adiabatic)
 * create adiabatic atmosphere (adiabatic atmosphere)
 * create adiabatic compression (adiabatic compression)
 * create adiabatic efficiency (adiabatic efficiency)
 * create adiabatic equivalent temperature (adiabatic equivalent temperature)
 * create adiabatic process (adiabatic process)
 * create adiabatic recovery temperature (adiabatic recovery temperature)
 * create adiabatic wall temperature (adiabatic wall temperature)
 * create A-display (A-display)
 * create ADP (ADP)
 * create adsorbate (adsorbate)
 * create adsorbent (adsorbent)
 * create adsorption (adsorption)
 * create advection (advection)
 * create advective (advective)
 * create aeon (aeon)
 * create A/E ratio (A/E ratio)
 * create aerial (aerial)
 * create aeroastromedicine (aeroastromedicine)
 * create aeroballistics (aeroballistics)
 * create aerobiology (aerobiology)
 * create aerodontalgia (aerodontalgia)
 * create aeroduct (aeroduct)
 * create aerodynamic (aerodynamic)
 * create aerodynamic coefficient (aerodynamic coefficient)
 * create aerodynamic force (aerodynamic force)
 * create aerodynamic heating (aerodynamic heating)
 * create aerodynamics (aerodynamics)
 * create aerodynamic trail (aerodynamic trail)
 * create aerodynamic vehicle (aerodynamic vehicle)
 * create aeroelasticity (aeroelasticity)
 * create aeroembolism (aeroembolism)
 * create aeroemphysema (aeroemphysema)
 * create aerolite (aerolite)
 * create aerology (aerology)
 * create aeronomy (aeronomy)
 * create aero-otitis media (aero-otitis media)
 * create aeropause (aeropause)
 * create aerophare (aerophare)
 * create aeropulse engine (aeropulse engine)
 * create aerosinusitis (aerosinusitis)
 * create aerosonator (aerosonator)
 * create aerospace (aerospace)
 * create aerospace medicine (aerospace medicine)
 * create aerospace vehicle (aerospace vehicle)
 * create aerothermodynamic border (aerothermodynamic border)
 * create aerothermodynamic duct (aerothermodynamic duct)
 * create aerothermodynamics (aerothermodynamics)
 * create aerothermoelasticity (aerothermoelasticity)
 * create AFC (AFC)
 * create afterbody (afterbody)
 * create afterburner (afterburner)
 * create afterburning (afterburning)
 * create aftercooling (aftercooling)
 * create afterglow (afterglow)
 * create afterheat (afterheat)
 * create AGE (AGE)
 * create age of the moon (age of the moon)
 * create aging (aging)
 * create Agiwarn (Agiwarn)
 * create agonic line (agonic line)
 * create agravic (agravic)
 * create agravic illusion (agravic illusion)
 * create air (air)
 * create air breakup (air breakup)
 * create airbreather (airbreather)
 * create airbreathing (airbreathing)
 * create aircraft (aircraft)
 * create aircraft rocket (aircraft rocket)
 * create airflow (airflow)
 * create airfoil (airfoil)
 * create airframe (airframe)
 * create airglow (airglow)
 * create air launch (air launch)
 * create air light (air light)
 * create air lock (air lock)
 * create air position indicator (air position indicator)
 * create airscoop (airscoop)
 * create air shower (air shower)
 * create airsickness (airsickness)
 * create air sounding (air sounding)
 * create airspace (airspace)
 * create air-space (air-space)
 * create air start (air start)
 * create airstream (airstream)
 * create air vane (air vane)
 * create air vehicle (air vehicle)
 * create Aitken dust counter (Aitken dust counter)
 * create Aitken nuclei (Aitken nuclei)
 * create
 * create Aitken nucleus counter (Aitken nucleus counter)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=albedo&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20The%20ratio%20of%20the%20amount%20of%20%5B%5Belectromagnetic%20radiation%5D%5D%20reflected%20by%20a%20body%20to%20the%20amount%20incident%20upon%20it%2C%20often%20expressed%20as%20a%20percentage%2C%20as%2C%20%27%27the%20albedo%20of%20the%20earth%20is%2034%25%27%27%20.%20Compare%20%5B%5BBond%20albedo%5D%5D.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AThe%20concept%20defined%20above%20is%20identical%20with%20%5B%5Breflectance%5D%5D.%20However%2C%20albedo%20is%20more%20commonly%20used%20in%20astronomy%20and%20meteorology%20and%20reflectance%20in%20physics.%20%3Cbr/%3EAlbedo%20is%20sometimes%20used%20to%20mean%20the%20flux%20of%20the%20reflected%20radiation%20as%2C%20the%20earth%20albedo%20is%200.64%20calorie%20per%20square%20centimeter.%20This%20usage%20should%20be%20discouraged.%20%3Cbr/%3E%20The%20albedo%20is%20to%20be%20distinguished%20from%20the%20%5B%5Bspectral%5D%5D%20reflectance%20which%20refers%20to%20one%20specific%20wavelength%20%28monochromatic%20radiation%29.%20%3Cbr/%3EUsage%20varies%20somewhat%20with%20regard%20to%20the%20exact%20wavelength%20interval%20implied%20in%20albedo%20figures%3B%20sometimes%20just%20the%20visible%20portion%20of%20the%20spectrum%20is%20considered%2C%20sometimes%20the%20totality%20of%20wavelengths%20in%20the%20solar%20spectrum.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create albedo] (albedo)
 * create albedometer (albedometer)
 * create Alford loop (Alford loop)
 * create Alfvén Mach number (Alfvén Mach number)
 * create Alfvén speed (Alfvén speed)
 * create Alfvén wave (Alfvén wave)
 * create alga (alga)
 * create algorism (algorism)
 * create algorithm (algorithm)
 * create alidade (alidade)
 * create alkali metal (alkali metal)
 * create all burnt (all burnt)
 * create all-inertial guidance (all-inertial guidance)
 * create alloy (alloy)
 * create alloying element (alloying element)
 * create almucantar (almucantar)
 * create alpha decay (alpha decay)
 * create alpha disintegration (alpha disintegration)
 * create alphanumeric (alphanumeric)
 * create alpha particle (alpha particle)
 * create alpha ray (alpha ray)
 * create altimeter (altimeter)
 * create altitude (altitude)
 * create altitude acclimatization (altitude acclimatization)
 * create altitude chamber (altitude chamber)
 * create altitude circle (altitude circle)
 * create altitude difference (altitude difference)
 * create altitude intercept (altitude intercept)
 * create altitude sickness (altitude sickness)
 * create altitude wind tunnel (altitude wind tunnel)
 * create alveolar air (alveolar air)
 * create alveolar oxygen pressure (alveolar oxygen pressure)
 * create alveoli (alveoli)
 * create AM (AM)
 * create ambient (ambient)
 * create ambient noise (ambient noise)
 * create ambiguity (ambiguity)
 * create American Ephemeris and Nautical Almanac (American Ephemeris and Nautical Almanac)
 * create American Nautical Almanac (American Nautical Almanac)
 * create ampere (ampere)
 * create amplidyne (amplidyne)
 * create amplifier (amplifier)
 * create amplitude (amplitude)
 * create amplitude-modulated indicator (amplitude-modulated indicator)
 * create amplitude modulation (amplitude modulation)
 * create AMR (AMR)
 * create anacoustic zone (anacoustic zone)
 * create analog (analog)
 * create analog computer (analog computer)
 * create analog output (analog output)
 * create analog to digital conversion (analog to digital conversion)
 * create analog to digital converter (analog to digital converter)
 * create
 * create analytical photography (analytical photography)
 * create AND (AND)
 * create And (And)
 * create AND circuit (AND circuit)
 * create AND gate (AND gate)
 * create AND-NOT gate (AND-NOT gate)
 * create Andromeda (Andromeda)
 * create aneroid (aneroid)
 * create angel (angel)
 * create angle (angle)
 * create angle modulation (angle modulation)
 * create angle of arrival (angle of arrival)
 * create angle of attack (angle of attack)
 * create angle of climb (angle of climb)
 * create angle of depression (angle of depression)
 * create angle of descent (angle of descent)
 * create angle of deviation (angle of deviation)
 * create angle of elevation (angle of elevation)
 * create angle of incidence (angle of incidence)
 * create angle of minimum deviation (angle of minimum deviation)
 * create angle of pitch (angle of pitch)
 * create angle of reflection (angle of reflection)
 * create angle of refraction (angle of refraction)
 * create angle of roll (angle of roll)
 * create angle of yaw (angle of yaw)
 * create angstrom (angstrom)
 * create Ångström compensation pyrheliometer (Ångström compensation pyrheliometer)
 * create Ångström pyrgeometer (Ångström pyrgeometer)
 * create angular acceleration (angular acceleration)
 * create angular distance (angular distance)
 * create angular frequency (angular frequency)
 * create angular momentum (angular momentum)
 * create angular rate (angular rate)
 * create angular resolution (angular resolution)
 * create angular speed (angular speed)
 * create angular velocity (angular velocity)
 * create anisotropic (anisotropic)
 * create annealing (annealing)
 * create annual parallax. (annual parallax.)
 * create annular (annular)
 * create annular eclipse (annular eclipse)
 * create anode (anode)
 * create anomalistic month (anomalistic month)
 * create anomalistic period (anomalistic period)
 * create anomalistic year (anomalistic year)
 * create anomalous dispersion (anomalous dispersion)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=anomalous%20propagation&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20The%20propagation%20of%20energy%20when%20it%20arrives%20at%20a%20destination%20via%20a%20path%20significantly%20different%20from%20the%20normally%20expected%20path.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AThe%20term%20is%20usually%20applied%20to%20the%20transmission%20of%20various%20forms%20of%20energy%20through%20the%20atmosphere%20when%2C%20in%20addition%20to%20the%20line-of-sight%20path%2C%20the%20energy%20is%20refracted%20by%20density%20discontinuities%20at%20one%20or%20more%20levels%20in%20atmosphere.%20Therefore%2C%20it%20propagates%20to%20a%20point%20that%20could%20not%20be%20reached%20via%20a%20line-of-sight%20path.%20In%20radio%20and%20radar%20studies%2C%20it%20refers%20to%20the%20abnormal%20%5B%5Brefraction%5D%5D%20of%20a%20beam%20of%20radio%20energy%2C%20usually%20applied%20to%20%5B%5Bsuperstandard%20propagation%5D%5D%20rather%20than%20to%20%5B%5Bsubstandard%20propagation%5D%5D.%20In%20either%20case%2C%20anomalous%20propagation%20results%20from%20an%20unusual%20vertical%20distribution%20of%20temperature%20and%20moisture%20in%20the%20atmosphere.%20%3Cbr/%3EThe%20anomalous%20propagation%20of%20sound%20refers%20to%20the%20downward%20refraction%20of%20an%20oblique%20sound%20wave%20from%20an%20explosion%2C%20the%20refraction%20occurring%20in%20the%20region%20of%20increasing%20temperature%20with%20height%20in%20the%20lower%20mesosphere.%20The%20anomalous%20propagation%20of%20sound%20has%20been%20used%20as%20a%20method%20for%20determining%20upper%20air%20temperatures%20and%20winds.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create anomalous propagation] (anomalous propagation)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=anomaly&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20In%20general%2C%20a%20deviation%20from%20the%20norm.%0A%23%20In%20geodesy%2C%20a%20deviation%20of%20an%20observed%20value%20from%20a%20theoretical%20value%2C%20due%20to%20an%20abnormality%20in%20the%20observed%20quantity.%0A%23%20In%20celestial%20mechanics%2C%20the%20angle%20between%20the%20%5B%5Bradius%20vector%5D%5D%20to%20an%20orbiting%20body%20from%20its%20primary%20%28the%20focus%20of%20the%20orbital%20ellipse%29%20and%20the%20%5B%5Bline%20of%20apsides%5D%5D%20of%20the%20orbit%2C%20measured%20in%20the%20direction%20of%20travel%2C%20from%20the%20point%20of%20closest%20approach%20to%20the%20primary%20%28perifocus%29.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AThe%20term%20defined%20above%20is%20usually%20called%20true%20anomaly%20v%20to%20distinguished%20it%20from%20the%20eccentric%20anomaly%20E%20which%20is%20measured%20at%20the%20center%20of%20the%20orbital%20ellipse%20to%20the%20projection%20of%20the%20body%20onto%20the%20auxiliary%20circle%20of%20the%20ellipse%2C%20or%20from%20the%20mean%20anomaly%20M%20which%20is%20what%20the%20true%20anomaly%20would%20become%20if%20the%20orbiting%20body%20had%20a%20uniform%20annular%20motion.%20The%20mean%20anomaly%20M%20can%20be%20computed%20by%20%3Cbr/%3E%20M%20%3D%20n%20%28t%20-%20T%29%20where%20n%20is%20mean%20motion%3B%20t%20is%20time%20of%20the%20computation%3B%20and%20T%20is%20time%20of%20perifocus.%20The%20eccentric%20anomaly%20E%20and%20the%20mean%20anomaly%20M%20are%20related%20by%20the%20Kepler%20equation%20%3Cbr/%3E%20M%20%3D%20E%20-%20e%20sin%20E%20where%20e%20is%20eccentricity%20of%20the%20ellipse.%20From%20E%2C%20the%20true%20anomaly%20v%20can%20be%20obtained%20by%20%3Cbr/%3E%20%3Cmath%3Etan%20v/2%3D%5B%281%2Be%29/%281-e%29%5D1/2%20tan%20E/2.%3C/math%3E%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create anomaly] (anomaly)
 * create anoxaemia (anoxaemia)
 * create anoxia (anoxia)
 * create Ant (Ant)
 * create antapex (antapex)
 * create antenna (antenna)
 * create antenna array (antenna array)
 * create antenna effect (antenna effect)
 * create antenna field (antenna field)
 * create antenna gain (antenna gain)
 * create antenna null (antenna null)
 * create antenna pair (antenna pair)
 * create antenna pattern (antenna pattern)
 * create antenna temperature (antenna temperature)
 * create anticyclonic (anticyclonic)
 * create antigravity (antigravity)
 * create anti-g suit (anti-g suit)
 * create anti-matter (anti-matter)
 * create antinode (antinode)
 * create anti-particle (anti-particle)
 * create antipode (antipode)
 * create antiresonance (antiresonance)
 * create antisolar point (antisolar point)
 * create Antlia (Antlia)
 * create apareon (apareon)
 * create apastron (apastron)
 * create aperiodic (aperiodic)
 * create aperture (aperture)
 * create aperture ratio (aperture ratio)
 * create apex of the sun's motion (apex of the sun's motion)
 * create apex of the sun's way (apex of the sun's way)
 * create aphelion (aphelion)
 * create apoapsis (apoapsis)
 * create apocenter (apocenter)
 * create apocynthion (apocynthion)
 * create apofocus (apofocus)
 * create apogee (apogee)
 * create apostilb (apostilb)
 * create apparent (apparent)
 * create apparent additional mass (apparent additional mass)
 * create apparent force (apparent force)
 * create apparent gravity (apparent gravity)
 * create apparent horizon (apparent horizon)
 * create apparent motion (apparent motion)
 * create apparent position (apparent position)
 * create apparent solar day (apparent solar day)
 * create apparent solar time (apparent solar time)
 * create apparent stresses (apparent stresses)
 * create apparent sun (apparent sun)
 * create apparent time (apparent time)
 * create apparent wander (apparent wander)
 * create Appleton layer (Appleton layer)
 * create approximate absolute temperature scale (approximate absolute temperature scale)
 * create appulse (appulse)
 * create apron (apron)
 * create Aps (Aps)
 * create apse (apse)
 * create apsides (apsides)
 * create apsis (apsis)
 * create APU (APU)
 * create Aql (Aql)
 * create Aquarius (Aquarius)
 * create aqueous vapor (aqueous vapor)
 * create Aquila (Aquila)
 * create Ara (Ara)
 * create Arago point (Arago point)
 * create arc (arc)
 * create arc discharge (arc discharge)
 * create arc spectrum (arc spectrum)
 * create arcs with ray structure (arcs with ray structure)
 * create arctic blackout (arctic blackout)
 * create ARDC model atmosphere (ARDC model atmosphere)
 * create areal radiant intensity (areal radiant intensity)
 * create areal velocity (areal velocity)
 * create area rule (area rule)
 * create areo (areo)
 * create areographic (areographic)
 * create areography (areography)
 * create Ares (Ares)
 * create Arg (Arg)
 * create Argo (Argo)
 * create argument (argument)
 * create argument of latitude (argument of latitude)
 * create argument of perigee (argument of perigee)
 * create Ari (Ari)
 * create Ariel (Ariel)
 * create Aries (Aries)
 * create arithmetic element (arithmetic element)
 * create arithmetic mean (arithmetic mean)
 * create arithmetic unit (arithmetic unit)
 * create array (array)
 * create arrhythmia (arrhythmia)
 * create arrow wing (arrow wing)
 * create artificial antenna (artificial antenna)
 * create artificial asteroid (artificial asteroid)
 * create artificial earth satellite (artificial earth satellite)
 * create artificial feel (artificial feel)
 * create artificial gravity (artificial gravity)
 * create artificial horizon (artificial horizon)
 * create artificial satellite (artificial satellite)
 * create A-scan (A-scan)
 * create ascendent (ascendent)
 * create ascending node (ascending node)
 * create A-scope (A-scope)
 * create asdic (asdic)
 * create Askania (Askania)
 * create aspect ratio (aspect ratio)
 * create aspects (aspects)
 * create aspiration condenser (aspiration condenser)
 * create assemble (assemble)
 * create assisted take-off (assisted take-off)
 * create associated corpuscular emission (associated corpuscular emission)
 * create assumed latitude (assumed latitude)
 * create assumed longitude (assumed longitude)
 * create A-station (A-station)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=asteroid&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3D%20%3D%3D%3D%0A%7B%7Ben-%20%7D%7D%0A%23%20One%20of%20the%20many%20small%20celestial%20bodies%20revolving%20around%20the%20sun%2C%20most%20of%20the%20orbits%20being%20between%20those%20of%20Mars%20and%20Jupiter.%20Also%20called%20%27%27planetoid%2C%20minor%20planet%27%27%20.%20See%20%5B%5Bplanet%5D%5D.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AThe%20term%20minor%20planet%20is%20preferred%20by%20many%20astronomers%20but%20asteroid%20continues%20to%20be%20used%20in%20astronomical%20literature%2C%20especially%20attributively%2C%20as%20in%20asteroid%20belt.%20%3Cbr/%3EAll%20asteroids%20with%20determined%20orbits%20%28except%20for%20a%20few%20discovered%20during%20World%20War%20II%29%20are%20numbered%20for%20identification%20in%20the%20order%20of%20their%20discovery.%20The%20Ephemerides%20of%20the%20Minor%20Planets%20published%20by%20the%20U.S.S.R.%20Academy%20of%20Sciences%20lists%20all%20numbered%20asteroids%2C%20data%20concerning%20them%2C%20and%20their%20predicted%20positions.%20The%20daily%20positions%20of%20the%20first%20four%20minor%20planets%20are%20tabulated%20in%20the%20American%20Ephemeris%20and%20Nautical%20Almanac.%20Orbits%20have%20been%20determined%20for%20approximately%201700%20asteroids.%20Asteroids%20have%20names%20as%20well%20as%20numbers%2C%20see%20%5B%5BTable%20I%5D%5D.%20The%20names%20are%20usually%20feminine%20but%20masculine%20names%20have%20been%20used%20for%20asteroids%20closer%20to%20or%20farther%20away%20from%20the%20Sun%20than%20the%20majority.%20The%20first%20asteroid%20to%20be%20given%20a%20masculine%20name%2C%20Eros%20%28number%20443%29%20was%20the%20first%20to%20be%20discovered%20inside%20the%20orbit%20of%20Mars.%20The%20Trojan%20asteroids%2C%20named%20for%20heroes%20of%20the%20Trojan%20war%2C%20are%20in%20the%20orbit%20of%20Jupiter.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create asteroid] (asteroid)
 * create astral dome (astral dome)
 * create astre fictif (astre fictif)
 * create astro (astro)
 * create astroballistics (astroballistics)
 * create astrobiology (astrobiology)
 * create astrocompass (astrocompass)
 * create astrodome (astrodome)
 * create astrodynamics (astrodynamics)
 * create astrogation (astrogation)
 * create astrographic position (astrographic position)
 * create astrolabe (astrolabe)
 * create astrometric position (astrometric position)
 * create astrometry (astrometry)
 * create astronaut (astronaut)
 * create astronautic centrifuge (astronautic centrifuge)
 * create astronautics (astronautics)
 * create astronavigation (astronavigation)
 * create astron machine (astron machine)
 * create astronomic (astronomic)
 * create astronomical (astronomical)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=astronomical%20constants&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20The%20elements%20of%20the%20orbits%20of%20the%20bodies%20of%20the%20solar%20system%2C%20their%20masses%20relative%20to%20the%20sun%2C%20their%20size%2C%20shape%2C%20orientation%2C%20rotation%2C%20and%20inner%20constitution%2C%20and%20the%20velocity%20of%20light.%0A%23%20%3D%20%5B%5Bsystem%20of%20astronomical%20constants%5D%5D.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AThe%20astronomical%20constants%20used%20in%20the%20calculations%20of%20The%20American%20Ephemeris%20and%20Nautical%20Almanac%2C%20as%20well%20as%20other%20national%20ephemerides%2C%20were%20adopted%20at%20various%20times%20between%201896%20and%201930.%20Although%20the%20system%20was%20known%20to%20contain%20many%20inconsistencies%2C%20the%20International%20Astronomical%20Union%20recommended%20their%20continued%20use%20in%201952.%20Space-related%20research%20has%20provided%20data%20for%20the%20computation%20of%20a%20more%20accurate%20system%2C%20and%20in%20January%201964%20The%20Working%20Group%20on%20the%20System%20of%20Astronomical%20Constants%20recommended%20a%20new%20system%20of%20constants%20to%20be%20introduced%20into%20the%20national%20and%20international%20ephemerides%20at%20the%20earliest%20practicable%20date.%20Both%20the%20conventional%20and%20revised%20systems%20are%20given%20in%20%5B%5BTable%20II%5D%5D.%20The%20constants%20in%20%5B%5BTable%20III%5D%5D%20were%20recommended%20for%20use%20in%20trajectory%20calculations%20for%20NASA%20programs%20by%20the%20Ad%20Hoc%20NASA%20Standards%20Constants%20Committee%20May%2016%2C%201963.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create astronomical constants] (astronomical constants)
 * create astronomical coordinates (astronomical coordinates)
 * create astronomical day (astronomical day)
 * create astronomical equator (astronomical equator)
 * create astronomical latitude (astronomical latitude)
 * create astronomical longitude (astronomical longitude)
 * create astronomical meridian (astronomical meridian)
 * create astronomical parallel (astronomical parallel)
 * create astronomical position (astronomical position)
 * create astronomical refraction (astronomical refraction)
 * create astronomical refraction error (astronomical refraction error)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=astronomical%20scintillation&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3D%20%3D%3D%3D%0A%7B%7Ben-%20%7D%7D%0A%23%20Any%20%5B%5Bscintillation%5D%5D%20phenomena%2C%20such%20as%20irregular%20oscillatory%20motion%2C%20variation%20of%20intensity%2C%20and%20color%20fluctuation%20observed%20in%20the%20light%20emanating%20from%20am%20extraterrestrial%20source%3B%20to%20be%20distinguished%20from%20%5B%5Bterrestrial%20scintillation%5D%5D%20primarily%20in%20that%20the%20light%20source%20for%20the%20latter%20lies%20somewhere%20within%20the%20earth%27s%20atmosphere.%20Also%20called%20%27%27stellar%20scintillation%27%27%20.%20See%20%5B%5Bseeing%5D%5D.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AAstronomical%20scintillation%20is%20typically%20strongest%20for%20celestial%20objects%20lying%20at%20large%20zenith%20distances%20and%20is%20not%20easily%20observed%20by%20eye%20for%20objects%20whose%20zenith%20distances%20are%20under%2030%C2%B0.%20Nonperiodic%20vibratory%20motions%20of%20stellar%20images%20with%20frequencies%20of%20the%20order%20of%201%20to%2010%20cycles%20per%20second%20create%20a%20troublesome%20problem%20of%20seeing%20in%20astronomical%20work.%20The%20size%20of%20the%20%5B%5Bschlieren%5D%5D%20producing%20vibratory%20scintillations%20has%20been%20estimated%20to%20be%20of%20the%20order%20of%20centimeters%2C%20and%20chromatic%20scintillations%20of%20celestial%20objects%20appear%20to%20be%20produced%20by%20parcels%20whose%20dimensions%20are%20of%20the%20order%20of%20decimeters%20or%2C%20perhaps%2C%20meters.%20Hence%2C%20astronomical%20scintillation%20is%20primarily%20a%20consequence%20of%20the%20high-frequency%2C%20short-wavelength%20type%20of%20atmospheric%20turbulence.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create astronomical scintillation] (astronomical scintillation)
 * create astronomical seeing (astronomical seeing)
 * create astronomical solar time (astronomical solar time)
 * create astronomical time (astronomical time)
 * create astronomical triangle (astronomical triangle)
 * create astronomical twilight (astronomical twilight)
 * create astronomical unit (astronomical unit)
 * create astronomical year (astronomical year)
 * create astronomy (astronomy)
 * create astrophysics (astrophysics)
 * create astrotracker (astrotracker)
 * create asynchronous computer (asynchronous computer)
 * create atelectasis (atelectasis)
 * create athodyd (athodyd)
 * create atmosphere (atmosphere)
 * create atmospheric boil (atmospheric boil)
 * create atmospheric boundary layer (atmospheric boundary layer)
 * create atmospheric braking (atmospheric braking)
 * create atmospheric duct (atmospheric duct)
 * create atmospheric electric field (atmospheric electric field)
 * create atmospheric electricity (atmospheric electricity)
 * create atmospheric entry (atmospheric entry)
 * create atmospheric interference (atmospheric interference)
 * create atmospheric ion (atmospheric ion)
 * create atmospheric layer (atmospheric layer)
 * create atmospheric noise (atmospheric noise)
 * create atmospheric optics (atmospheric optics)
 * create atmospheric oscillation (atmospheric oscillation)
 * create atmospheric physics (atmospheric physics)
 * create atmospheric pressure (atmospheric pressure)
 * create atmospheric radiation (atmospheric radiation)
 * create atmospheric region (atmospheric region)
 * create atmospheric refraction (atmospheric refraction)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=atmospherics&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20The%20%5B%5Bradiofrequency%5D%5D%20electromagnetic%20radiation%20originating%2C%20principally%2C%20in%20the%20irregular%20surges%20of%20charge%20in%20thunderstorm%20lightning%20discharges.%20Atmospherics%20are%20heard%20as%20a%20quasi-steady%20background%20or%20crackling%20noise%20%28static%29%20in%20ordinary%20amplitude-modulated%20radio%20receivers.%20Also%20called%20%27%27atmospheric%20interference%2C%20strays%2C%20sferics%27%27%20.%20See%20%5B%5Bsferics%5D%5D.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0ASince%20any%20acceleration%20of%20electric%20charge%20leads%20to%20emission%20of%20electromagnetic%20radiation%2C%20and%20since%20the%20several%20processes%20involved%20in%20propagation%20of%20lightning%20lead%20to%20very%20large%20charge%20accelerations%2C%20the%20lightning%20channel%20acts%20like%20a%20huge%20transmitter%2C%20sending%20out%20broad%20band%20radiation%3B%20the%2010-kilocycle%20range%20propagates%20best%20and%20is%20used%20in%20detecting%20atmospherics.%20Atmospherics%20may%20occasionally%20be%20detected%20at%20distances%20in%20excess%20of%202000%20miles%20from%20their%20source.%20Advantage%20has%20been%20taken%20of%20this%20in%20using%20radio%20direction-finding%20equipment%20to%20locate%20active%20thunderstorm%20areas%20in%20remote%20regions%20and%20in%20between%20weather%20reporting%20stations.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create atmospherics] (atmospherics)
 * create atmospheric scintillation (atmospheric scintillation)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=atmospheric%20shell&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3D%20%3D%3D%3D%0A%7B%7Ben-%20%7D%7D%0A%23%20Any%20one%20of%20a%20number%20of%20strata%20or%20layers%20of%20the%20earth%27s%20atmosphere.%20Also%20called%20%27%27atmospheric%20layer%2C%20atmospheric%20region%27%27%20.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0ATemperature%20distribution%20is%20the%20most%20common%20criterion%20used%20for%20denoting%20the%20various%20shells.%20The%20troposphere%20%28the%20region%20of%20change%29%20is%20the%20lowest%2010%20or%2020%20kilometers%20of%20the%20atmosphere%2C%20characterized%20by%20decreasing%20temperature%20with%20height.%20The%20top%20of%20the%20troposphere%20is%20called%20the%20tropopause.%20Above%20the%20tropopause%2C%20the%20stratosphere%2C%20a%20region%20in%20which%20the%20temperature%20generally%20increases%20with%20altitude%2C%20extends%20to%20the%20%5B%5Bstratopause%5D%5D%2C%20the%20top%20of%20the%20inversion%20layer%2C%20at%20about%2050%20to%2055%20kilometers.%20Above%20the%20stratosphere%2C%20the%20mesosphere%2C%20a%20region%20of%20generally%20decreasing%20temperatures%20with%20height%20extends%20to%20the%20mesopause%2C%20the%20base%20of%20an%20inversion%20layer%20at%20about%2080%20to%2085%20kilometers.%20The%20region%20above%20the%20mesopause%2C%20in%20which%20temperature%20generally%20increases%20with%20height%2C%20is%20the%20thermosphere.%20%3Cbr/%3EThe%20distribution%20of%20various%20physicochemical%20processes%20is%20another%20criterion.%20The%20ozonosphere%2C%20lying%20roughly%20between%2010%20and%2050%20kilometers%2C%20is%20the%20general%20region%20of%20the%20upper%20atmosphere%20in%20which%20there%20is%20an%20appreciable%20ozone%20concentration%20and%20in%20which%20ozone%20plays%20an%20important%20part%20in%20the%20radiative%20balance%20of%20the%20atmosphere%3B%20the%20ionosphere%2C%20starting%20at%20about%2070%20or%2080%20kilometers%2C%20is%20the%20region%20in%20which%20ionization%20of%20one%20or%20more%20of%20the%20atmospheric%20constituents%20is%20significant%3B%20the%20neutrosphere%20is%20the%20shell%20below%20this%20which%20is%2C%20by%20contrast%2C%20relatively%20unionized%3B%20and%20the%20chemosphere%2C%20with%20no%20very%20definite%20height%20limits%2C%20is%20the%20region%20in%20which%20photochemical%20reactions%20take%20place.%20%3Cbr/%3EDynamic%20and%20kinetic%20processes%20are%20a%20third%20criterion.%20The%20exosphere%20is%20the%20region%20at%20the%20top%20of%20the%20atmosphere%2C%20above%20the%20critical%20level%20of%20escape%2C%20in%20which%20atmospheric%20particles%20can%20move%20in%20free%20orbits%2C%20subject%20only%20to%20the%20earth%27s%20gravitation.%20%3Cbr/%3EComposition%20is%20a%20fourth%20criterion.%20The%20homosphere%20is%20the%20shell%20in%20which%20there%20is%20so%20little%20photodissociation%20or%20gravitational%20separation%20that%20the%20mean%20molecular%20weight%20of%20the%20atmosphere%20is%20sensibly%20constant%3B%20the%20heterosphere%20is%20the%20region%20above%20this%2C%20where%20the%20atmospheric%20composition%20and%20mean%20molecular%20weight%20are%20not%20constant.%20The%20boundary%20between%20the%20two%20is%20probably%20at%20the%20level%20at%20which%20molecular%20oxygen%20begins%20to%20be%20dissociated%2C%20and%20this%20occurs%20in%20the%20vicinity%20of%2080%20or%2090%20kilometers.%20%3Cbr/%3EThe%20term%20mesosphere%20has%20been%20given%20another%20definition%20which%20does%20not%20fit%20into%20any%20logical%20set%20of%20criteria%2C%20i.e.%2C%20the%20shell%20between%20the%20exosphere%20and%20the%20ionosphere.%20This%20use%20of%20mesosphere%20has%20not%20been%20widely%20accepted.%20%3Cbr/%3EFor%20further%20subdivisions%2C%20see%20%5B%5Bionosphere%5D%5D%2C%20%5B%5Btroposphere%5D%5D%2C%20%5B%5Bgeocorona%5D%5D.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create atmospheric shell] (atmospheric shell)
 * create atmospheric shimmer (atmospheric shimmer)
 * create atmospheric tide (atmospheric tide)
 * create atmospheric transmissivity (atmospheric transmissivity)
 * create atomic clock (atomic clock)
 * create atomic mass (atomic mass)
 * create atomic mass unit (atomic mass unit)
 * create atomic number (atomic number)
 * create atomic particle (atomic particle)
 * create atomic rocket (atomic rocket)
 * create atomic weight (atomic weight)
 * create atomic weight unit (atomic weight unit)
 * create A-trace (A-trace)
 * create attached shock (attached shock)
 * create attached shock wave (attached shock wave)
 * create attachment (attachment)
 * create attachment coefficient (attachment coefficient)
 * create attenuation (attenuation)
 * create attenuation coefficient (attenuation coefficient)
 * create attenuation constant (attenuation constant)
 * create attenuation factor (attenuation factor)
 * create attenuation length (attenuation length)
 * create attenuation ratio (attenuation ratio)
 * create attitude (attitude)
 * create attitude control (attitude control)
 * create attitude gyro (attitude gyro)
 * create attitude jet (attitude jet)
 * create attribute (attribute)
 * create attributes testing (attributes testing)
 * create AU (AU)
 * create audible sound (audible sound)
 * create audio (audio)
 * create audio frequency (audio frequency)
 * create audio frequency range (audio frequency range)
 * create audiorange (audiorange)
 * create auditory sensation area (auditory sensation area)
 * create Auger shower (Auger shower)
 * create augmentation (augmentation)
 * create augmentation correction (augmentation correction)
 * create augmenter tube (augmenter tube)
 * create Aur (Aur)
 * create aural null (aural null)
 * create Auriga (Auriga)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=aurora&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20The%20sporadic%20radiant%20emission%20from%20the%20%5B%5Bupper%20atmosphere%5D%5D%20over%20middle%20and%20high%20latitudes.%20It%20is%20believed%20to%20be%20due%20primarily%20to%20the%20%5B%5Bemission%5D%5D%20from%20nitrogen%20-%20atomic%20N%20I%20and%20N%20II%2C%20molecular%2C%20N%3Csub%3E2%3C/sub%3E%2C%20and%20ionic%20N%3Csub%3E2%3C/sub%3E%2B%3B%20atomic%20oxygen%20%28O%20I%20and%20O%20II%29%3B%20atomic%20sodium%20%28Na%20I%29%3B%20the%20hydroxyl%20radical%20%28OH%29%3B%20and%20hydrogen.%20Compare%20%5B%5Bairglow%5D%5D.%0A%23%20I.%20Forms%20without%20ray%20structure%3A%0A%23%20HA%20%28abbr%20for%20homogeneous%20quiet%20area%29.%20These%20can%20appear%20near%20the%20horizon%2C%20and%20between%20the%20arc%20and%20the%20horizon%20a%20dark%20segment%20is%20often%20seen.%20These%20arcs%20can%20be%20narrow%20or%20broad%2C%20and%20are%20very%20often%20diffuse%20along%20the%20upper%20border%20but%20sharp%20along%20the%20lower%20one.%20%3Cbr/%3EHB%20%28abbr%20for%20homogeneous%20bands%29.%20These%20forms%20do%20not%20have%20the%20regular%20shape%20of%20the%20arcs%3B%20they%20are%20more%20rapidly%20moving%20phenomena.%20The%20lower%20border%20is%20often%20irregular%20and%20sharp.%20The%20breadth%20can%20vary%20from%20a%20very%20narrow%20band%20to%20a%20band%20which%20is%20so%20large%20that%20it%20resembles%20a%20curtain%20hanging%20down.%20These%20bands%20very%20often%20turn%20into%20bands%20with%20ray%20structure.%20%3Cbr/%3EPA%20%28abbr%20for%20pulsating%20arcs%29.%20Parts%20of%20an%20arc%20flash%20up%20and%20disappear%20regularly%20within%20a%20period%20of%20about%2020%20seconds.%20This%20form%20quite%20often%20stands%20isolated%20in%20the%20sky%20without%20other%20auroras.%20%3Cbr/%3EDS%20%28abbr%20for%20diffuse%20luminous%20surfaces%29.%20These%20either%20appear%20like%20a%20diffuse%20veil%20or%20glow%20over%20great%20parts%20of%20the%20heavens%20without%20distinct%20boundaries%2C%20often%20appearing%20after%20intense%20displays%20of%20rays%20and%20curtains%2C%20or%20as%20more%20isolated%20feeble%20luminous%20streaks%20which%20sometimes%20bear%20a%20striking%20resemblance%20to%20clouds.%20Sometimes%20large%20areas%20of%20the%20heavens%20can%20be%20discolored%20by%20a%20green%2C%20violet%2C%20or%20red%20diffuse%20light.%20%3Cbr/%3EPS%20%28abbr%20for%20pulsating%20surfaces%29.%20Diffuse%20patches%20appear%20and%20disappear%20rhythmically%20at%20the%20same%20place%2C%20retaining%20the%20same%20irregular%20shape%2C%20When%20the%20patches%20are%20lying%20near%20the%20magnetic%20zenith%20the%20contours%20can%20be%20more%20sharp%2C%20and%20form%20a%20sort%20of%20corona.%20These%20forms%20appear%20often%20in%20connection%20with%20flaming%20auroras.%20%3Cbr/%3EG%20%28abbr%20for%20feeble%20glow%20near%20the%20horizon%20resembling%20the%20dawn%29.%20Of%20white%20or%20redlike%20color%2C%20this%20form%20is%20often%20the%20upper%20part%20of%20an%20arc%20whose%20lower%20border%20is%20below%20the%20horizon.%0A%23%20II.%20Forms%20with%20ray%20structure%3A%20These%20forms%20consist%20of%20short%20or%20long%20rays%20which%20can%20be%20arranged%20in%20different%20ways.%0A%23%20RA%20%28abbr%20for%20arcs%20with%20ray%20structure%29.%20A%20homogeneous%20arc%20which%20has%20remained%20quiet%20and%20unaltered%20for%20a%20rather%20long%20time%20may%20become%20sharp%20and%20luminous%20along%20the%20lower%20border%20and%20they%20very%20rapidly%20change%20into%20an%20arc%20of%20rays.%20The%20rays%20can%20be%20short%20or%20long.%20%3Cbr/%3ERBI%20%28abbr%20for%20bands%20with%20ray%20structure%29.%20These%20resemble%20the%20bands%20mentioned%20under%20HB%20but%20are%20constituted%20of%20a%20series%20of%20rays%20which%20are%20arranged%20close%20to%20each%20other%20along%20the%20band%2C%20or%20they%20can%20appear%20more%20scattered.%20Often%20a%20series%20of%20parallel%20bands%20appear.%20When%20a%20band%20is%20near%20the%20magnetic%20zenith%20is%20may%20have%20the%20form%20of%20a%20corona.%20%3Cbr/%3ED%20%28abbr%20for%20draperies%29.%20If%20the%20ray%20become%20very%20long%20the%20band%20appears%20like%20a%20curtain%20or%20drapery%20whose%20lower%20border%20is%20often%20more%20luminous.%20Several%20parallel%20curtains%20frequently%20appear%20at%20the%20same%20time.%20Near%20the%20zenith%20the%20curtain%20may%20have%20a%20fanlike%20form%20on%20account%20of%20the%20perspective.%20%3Cbr/%3ER%20%28abbr%20for%20rays%29.%20The%20rays%20can%20be%20isolated%2C%20narrow%20or%20broad%2C%20short%20or%20long.%20They%20may%20appear%20in%20great%20segments%20or%20like%20masses%20or%20rays%2C%20very%20often%20resembling%20curtains.%20%3Cbr/%3EC%20%28abbr%20for%20corona%29.%20When%20the%20rays%20approach%20the%20magnetic%20zenith%20they%20seem%2C%20on%20account%20of%20the%20perspective%2C%20to%20converge%20to%20this%20point%20and%20form%20a%20corona.%20This%20may%20be%20formed%20by%20long%20rays%20or%20by%20short%20ones%2C%20it%20may%20be%20completed%20or%20incomplete.%20A%20corona%20can%20also%20be%20formed%20by%20bands%2C%20draperies%2C%20or%20more%20diffuse%20forms%20near%20the%20magnetic%20zenith.%0A%23%20III.%20Flaming%20auroras%20%28abbr%20F%29.%20A%20characteristic%2C%20rapidly%20moving%20form%2C%20consisting%20of%20strong%20waves%20of%20light%20which%20move%20upwards%2C%20one%20after%20the%20other%2C%20in%20the%20direction%20of%20the%20magnetic%20zenith.%20The%20waves%20have%20the%20form%20of%20detached%20arcs%20which%20move%20upwards%20normally%20to%20the%20direction%20of%20the%20arc%3B%20they%20can%20be%20compared%20to%20invisible%20waves%20illuminating%20broad%20rays%20and%20patches%20which%20appear%20and%20disappear%20rhythmically%20when%20the%20waves%20pass%20them.%20The%20flaming%20aurora%20frequently%20appears%20after%20strong%20displays%20of%20rays%20and%20curtains%20and%20is%20often%20followed%20by%20the%20formation%20of%20a%20corona.%20For%20more%20information%2Cabout%20auroras%2C%20visit%20%5B%5BAuroras%3A%20Paintings%20in%20the%20Sky%5D%5D.%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AAccording%20to%20various%20theories%2C%20auroras%20seem%20definitely%20to%20be%20related%20to%20magnetic%20storms%20and%20the%20influx%20of%20charged%20particles%20from%20the%20sun.%20The%20exact%20details%20of%20the%20nature%20of%20the%20mechanisms%20involved%20are%20still%20being%20investigated%2C%20but%20release%20of%20trapped%20particles%20from%20Van%20Allen%20belt%20apparently%20plays%20an%20important%20part.%20The%20aurora%20is%20most%20intense%20at%20times%20of%20magnetic%20storms%20%28when%20it%20is%20also%20observed%20farthest%20equatorward%29%2C%20and%20shows%20a%20periodicity%20which%20is%20related%20to%20the%20sun%27s%2027-day%20rotation%20period%20and%20the%2011-year%20sunspot%20cycle.%20The%20distribution%20with%20height%20shows%20a%20pronounced%20maximum%20near%20100%20kilometers.%20The%20lower%20limit%20is%20probably%20near%2080%20kilometers.%20%3Cbr/%3EThe%20aurora%20can%20often%20be%20clearly%20seen%2C%20and%20it%20assumes%20a%20variety%20of%20shapes%20and%20colors%20which%20are%20characteristic%20patterns%20of%20auroral%20emission.%20%3Cbr/%3EThe%20following%20is%20the%20general%20classification%20and%20abbreviations%20of%20the%20forms%20of%20the%20auroras%20adopted%20by%20the%20International%20Union%20of%20Geodesy%20and%20Geophysics%20in%201930%20for%20reporting%20of%20visual%20observations.%20The%20classification%20was%20modified%20slightly%20and%20expanded%20in%201963.%20The%20new%20classification%20is%20described%20in%20the%27%27%20%27%27International%20Auroral%20Atlas%27%27%20%27%27%2C%20Aldine%20Pub.%20Co.%2C%20Chicago%2C%201963.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create aurora] (aurora)
 * create aurora australis (aurora australis)
 * create aurora borealis (aurora borealis)
 * create auroral zone (auroral zone)
 * create aurora polaris (aurora polaris)
 * create austausch coefficient (austausch coefficient)
 * create australite (australite)
 * create authorized carrier frequency (authorized carrier frequency)
 * create autoconvection gradient (autoconvection gradient)
 * create autoconvective lapse rate (autoconvective lapse rate)
 * create autocorrelation (autocorrelation)
 * create autocorrelation function (autocorrelation function)
 * create autoigniting propellant (autoigniting propellant)
 * create autoignition temperature (autoignition temperature)
 * create autokinetic illusion (autokinetic illusion)
 * create automatic celestial navigation (automatic celestial navigation)
 * create automatic computer (automatic computer)
 * create automatic control (automatic control)
 * create automatic data processing system (automatic data processing system)
 * create automatic direction finder (automatic direction finder)
 * create automatic frequency control (automatic frequency control)
 * create automatic gain control (automatic gain control)
 * create automatic pilot (automatic pilot)
 * create automatic stability (automatic stability)
 * create automatic tracking (automatic tracking)
 * create autopilot (autopilot)
 * create autosyn (autosyn)
 * create autosynchronous (autosynchronous)
 * create autumnal equinox (autumnal equinox)
 * create auxiliary circle (auxiliary circle)
 * create auxiliary fluid ignition (auxiliary fluid ignition)
 * create auxiliary landing gear (auxiliary landing gear)
 * create auxiliary power unit (auxiliary power unit)
 * create avalanche (avalanche)
 * create average (average)
 * create average deviation (average deviation)
 * create average information content (average information content)
 * create aviation medicine (aviation medicine)
 * create Avogadro constant (Avogadro constant)
 * create Avogadro law (Avogadro law)
 * create Avogadro number (Avogadro number)
 * create axial flow compressor (axial flow compressor)
 * create axis (axis)
 * create axis of freedom (axis of freedom)
 * create axis of thrust (axis of thrust)
 * [http://en.wiktionary.org/w/index.php?action=edit&title=azimuth&preloadtext=%3D%3DEnglish%3D%3D%0A%3D%3D%3DNoun%3D%3D%3D%0A%7B%7Ben-noun%7D%7D%0A%23%20Horizontal%20direction%20or%20%5B%5Bbearing%5D%5D.%20Compare%20%5B%5Bazimuth%20angle%5D%5D.%0A%23%20In%20navigation%2C%20the%20horizontal%20direction%20of%20a%20%5B%5Bcelestial%5D%5D%20point%20from%20a%20%5B%5Bterrestrial%5D%5D%20point%2C%20expressed%20as%20the%20angular%20distance%20from%20a%20reference%20direction%2C%20usually%20measured%20from%200%C2%B0%20at%20the%20reference%20direction%20clockwise%20through%20360%C2%B0.%0A%23%20In%20astronomy%2C%20the%20direction%20of%20a%20celestial%20point%20from%20a%20terrestrial%20point%20measured%20clockwise%20from%20the%20north%20or%20the%20south%20point%20of%20the%20%5B%5Bmeridian%5D%5D%20plane.%20See%20%5B%5Bhorizon%20system%5D%5D.%0A%23%20In%20surveying%2C%20the%20horizontal%20direction%20of%20an%20object%20measured%20clockwise%20from%20the%20%27%27south%20point%20of%20the%20meridian%20plane.%0A%23%20In%20surveying%2C%20an%20azimuth%20of%20a%20celestial%20body%20is%20called%20an%20astronomic%20azimuth.%27%27%0A%0A%3D%3D%3D%3DUsage%20notes%3D%3D%3D%3D%0AAn%20azimuth%20is%20often%20designated%20as%20true%2C%20magnetic%2C%20compass%2C%20grid%2C%20or%20relative%20as%20the%20reference%20direction%20is%20true%2C%20magnetic%2C%20compass%2C%20grid%20north%2C%20or%20heading%2C%20respectively.%20Unless%20otherwise%20specified%2C%20the%20term%20is%20generally%20understood%20to%20apply%20to%20true%20azimuth%2C%20which%20may%20be%20further%20defined%20as%20the%20arc%20of%20the%20horizon%2C%20or%20the%20angle%20at%20the%20zenith%2C%20between%20the%20north%20part%20of%20the%20celestial%20%5B%5Bmeridian%5D%5D%20or%20principal%20vertical%20circle%20and%20a%20vertical%20circle%2C%20measured%20from%200%C2%B0%20at%20the%20north%20part%20of%20the%20principal%20vertical%20circle%20clockwise%20through%20360%C2%B0.%0A%0A%3D%3D%3D%3DReferences%3D%3D%3D%3D%0A%2A%20%7B%7BR%3ANASA%201965%7D%7D create azimuth] (azimuth)
 * create azimuth angle (azimuth angle)
 * create azimuth error (azimuth error)
 * create azimuth marker (azimuth marker)
 * create azran (azran)
 * create Azusa (Azusa)