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(Click for frequent words.) 73 auroras 72 aurora borealis 68 auroral 67 aurorae 64 auroral displays 64 Aurora Borealis 61 meteor shower 61 X ray emission 61 substorm 59 substorms 59 noctilucent clouds 59 Epsilon Aurigae 59 zodiacal light 58 Geminids meteor shower 58 X ray wavelengths 58 pulsating aurora 58 Orionids 58 auroral activity 57 Quadrantid meteor shower 57 Geminids 57 Taurids 57 Quadrantids 57 Comet Lulin 57 sunspot 57 auroras borealis 57 occultation 57 Perseids 57 Comet Holmes 57 afterglows 57 constellation Cassiopeia 56 eclipsing binary 56 polar vortex 56 Lyrids 56 magnetospheric 56 Perseid meteor shower 56 gamma ray burst 56 Leonids 56 solar corona 56 meteor showers 56 nebula 56 airglow 56 celestial phenomenon 56 Perseid meteor 56 Aurora borealis 56 Orionid 56 Noctilucent clouds 56 reflection nebula 55 GRB #B 55 meteors 55 Orion Nebula 55 Sunspots 55 GRB# 55 sunspots 55 earthshine 55 Geminid meteor shower 55 predawn sky 55 Crab Nebula 55 constellation Aquarius 55 Upsilon Andromedae 55 Kuiper Belt Objects 54 gamma ray bursts 54 photosphere 54 gamma ray emission 54 constellation Perseus 54 magnetar 54 Meteor Shower 54 cosmic ray 54 exoplanetary 54 transiting planet 54 annular eclipse 54 GRBs 54 geomagnetic disturbances 54 Leonid meteors 54 Orionid meteor shower 54 Lagoon Nebula 54 cryovolcanism 54 Meteor shower 54 quasar 54 nightglow 54 X ray pulses 54 XMM Newton 53 Perseids meteor shower 53 coronal mass ejection 53 skywatchers 53 comet 53 geomagnetic 53 constellation Centaurus 53 supernova 53 astronomers 53 Leonid shower 53 Lyman alpha 53 sun corona 53 reddish glow 53 cosmic ray flux 53 cosmological distances 53 Leonid meteor shower 53 occultations 53 supernova remnant 53 AGNs 53 magnetic reconnection 53 TGFs 53 planetary transits 53 infrared wavelength 53 geomagnetic storms 53 SpaceWeather.com 53 astronomical objects 53 aurora australis 53 GJ #b [002] 53 Saturn aurora 53 geomagnetic activity 53 spaceweather.com 53 Delta Aquarids 53 SN #A 53 blazar 53 Leonid meteor showers 53 RHESSI 53 comet Lulin 53 unaided eye 53 eruptive activity 53 coronal holes 53 Pleiades star 53 distant galaxy 53 ultraviolet wavelengths 53 nebulae 53 Eta Aquarids 53 coronal loops 53 polarimetry 53 spiral galaxy NGC 52 Helix nebula 52 proplyds 52 meteor fireball 52 RS Ophiuchi 52 Saturn auroras 52 Lunar eclipse 52 celestial sphere 52 occulted 52 constellation Orion 52 diffuse aurora 52 Gamma ray bursts 52 relativistic particles 52 Perseid meteors 52 KH #D 52 solar flares 52 HD# [002] 52 comet Hale Bopp 52 convective clouds 52 moon Enceladus 52 gravitational waves 52 celestial object 52 starburst galaxies 52 Aurigid 52 coronal loop 52 Alfven waves 52 lunar eclipses 52 constellation Cygnus 52 GALEX 52 Comet Hartley 2 52 quasars 52 slender crescent 52 Cassiopeia 52 comet McNaught 52 extrasolar planet 52 Perseus constellation 52 blazars 52 fainter objects 52 constellations 52 Helix Nebula 52 Earth ionosphere 52 auroral oval 52 Eta Aquarid meteor shower 52 gravitational lensing 52 Orion constellation 52 supergiant star 52 galactic cosmic rays 52 fireball streaking 51 Comet NEAT 51 stellar occultations 51 volcanic plumes 51 Comet McNaught 51 GRB # 51 ionized hydrogen 51 skywatching 51 gamma ray observatory 51 noctilucent 51 Saturn rings 51 Saturn moon Enceladus 51 celestial equator 51 constellation Sagittarius 51 supermoon 51 Meteor showers 51 constellation Leo 51 Lulin 51 emission nebula 51 THEMIS 51 produce colorful auroras 51 Fermi telescope 51 lunar perigee 51 HD#b 51 dynamical processes 51 Perseid meteor showers 51 red supergiant 51 extrasolar planets 51 Syrtis Major 51 extrasolar planetary systems 51 Rossby waves 51 periodicities 51 solar prominences 51 planetary nebula 51 type Ia supernova 51 barred spiral galaxy 51 waxing gibbous moon 51 meridional flow 51 sunspot cycle 51 SOHO spacecraft 51 ionospheric 51 constellation Auriga 51 gravitational microlensing 51 HF propagation 51 RXTE 51 gamma ray flares 51 Oort Cloud 51 Andromeda galaxy 51 constellation Virgo 51 Solar Dynamics Observatory 51 moon Io 51 constellation Bootes 51 heliosphere 51 Ophiuchi 51 HD #b [002] 51 Carina constellation 51 RRATs 51 lunar eclipse 50 backscattered 50 X ray telescopes 50 Leonid Meteor Shower 50 Voorwerp 50 comet Tempel Tuttle 50 waning gibbous moon 50 HII regions 50 ionized gases 50 Rosette Nebula 50 geomagnetic storm 50 Geminid meteors 50 auroral emissions 50 Galaxy Evolution 50 Hanny Voorwerp 50 Red Rectangle 50 infrared radiation 50 X ray afterglow 50 Geminid shower 50 Andromeda Galaxy 50 moonrise 50 Enceladus 50 Omega Centauri 50 Perseid Meteor Shower 50 neutron star 50 Spaceweather.com 50 Orion nebula 50 planetary nebulae 50 convective 50 polar stratospheric 50 sundog 50 astronomer 50 amateur astronomer 50 extragalactic 50 ionosphere 50 celestial objects 50 Gamma Virginids 50 Cepheids 50 atmospheric turbulence 50 Jupiter Uranus 50 Geminid 50 energetic electrons 50 Pleiades cluster 50 cometary debris 50 flyby 50 meteor 50 magnetosphere 50 globular cluster M# 50 Gravitational waves 50 Galactic Plane 50 Saturnian moons 50 annular solar eclipse 50 constellation Ursa Major 50 novae 50 mesospheric 50 Comet Hale Bopp 50 Ring Nebula 50 Halley comet 50 COROT 50 Fomalhaut b 50 bolide 50 Comet Machholz 50 polar mesospheric clouds 50 constellation Andromeda 50 galaxy NGC 50 planetary nebulas 50 NASA Aqua 50 VIRTIS 50 star Spica 50 total lunar eclipse 50 volcanism 50 planets Uranus 50 Eta Carinae 50 infrared wavelengths 50 Leonid meteor 50 STEREO spacecraft 50 millimeter wavelength 49 lenticular clouds 49 orbiting gamma ray 49 constellation Lyra 49 asterism 49 pulsars 49 waxing crescent moon 49 stellar occultation 49 Scorpii 49 sunspot activity 49 optical wavelengths 49 glowing brightly 49 Earth magnetosphere 49 supernovae 49 starburst galaxy 49 noctilucent cloud 49 skywatcher 49 Virgo Cluster 49 Kuiper belt objects 49 stellar nurseries 49 habitable planets 49 astrophysical 49 Earth magnetotail 49 thin crescent moon 49 SN #gy 49 gravitational lens 49 interstellar dust 49 constellation Taurus 49 Digitized Sky Survey 49 supernova remnants 49 Comet Halley 49 Great Orion Nebula 49 electron neutrinos 49 Keck Telescope 49 Lunar Eclipse 49 oscillations 49 Comet LINEAR 49 surface plasmons 49 Alfvén waves 49 obscuration 49 innermost planet 49 sodium atoms 49 exosphere 49 WASP #b 49 Corot 9b 49 Jupiter moon Io 49 moonset 49 spectral fingerprint 49 Heliospheric Observatory SOHO 49 Gliese #c 49 planet Uranus 49 tropospheric 49 Mimas 49 Cassini flyby 49 Perseid shower 49 Sagittarius B2 49 Saturn magnetosphere 49 Composite Infrared Spectrometer 49 constellation Ophiuchus 49 arcminutes 49 Saturnian moon 49 active galactic nuclei 49 Milankovitch cycles 49 Puppis 49 midlatitudes 49 Titan flyby 49 nebulosity 49 interstellar dust clouds 49 CMB radiation 49 Pleiades 49 Beta Pictoris b 49 magnetars 49 polar 49 Corot 7b 49 gibbous moon 49 Sunspot 49 coronal mass ejections 49 elliptical galaxy 49 Doppler shifts 49 neutrino 48 Paranal Chile 48 constellation Scorpius 48 Lyrid meteor shower 48 Geomagnetic storms 48 ecliptic 48 extrasolar 48 exoplanets orbiting 48 galactic alignment 48 planets orbiting stars 48 lightning flashes 48 cirrus 48 gaseous planet 48 Toutatis 48 Extrasolar planets 48 Higgs particle 48 Venusian atmosphere 48 filamentary structure 48 distant galaxies 48 Mpc 48 Evolution Explorer 48 Trifid Nebula 48 Aqua satellite 48 starlight 48 gravitational radiation 48 meteor sightings 48 elongated orbits 48 magnetotail 48 transiting planets 48 radial velocity 48 Stephan Quintet 48 Dynamics Observatory 48 globular cluster 48 binary asteroid 48 astronomy 48 TrES 4 48 Saturn moon Iapetus 48 Galilean satellites 48 HM Cancri 48 Trapezium 48 starbursts 48 radiative cooling 48 X ray binary 48 southern constellation Carina 48 V# Sgr 48 Cepheid variable 48 solitons 48 particle acceleration 48 explosive eruptions 48 supernova SN 48 Microlensing 48 Cosmic Microwave Background 48 planetary conjunctions 48 Ulysses spacecraft 48 mid latitudes 48 iridescence 48 supersymmetric particles 48 fading afterglow 48 infrared spectral 48 accretion disk 48 dwarf galaxy 48 cosmic ray intensity 48 Maunder Minimum 48 Hinode 48 CMEs 48 atmospheric phenomena 48 Galilean moons 48 microquasar 48 Delta Cephei 48 ejecta 48 Gamma ray burst 48 Bug Nebula 48 Triangulum Galaxy 48 Perseids Meteor Shower 48 constellation Cetus 48 constellation Gemini 48 Crab Pulsar 48 luminosities 48 Earthlike planets 48 ray Space Telescope 48 interstellar clouds 48 planets orbits 48 elliptical galaxies 48 mantle plumes 48 comet nucleus 48 ionised gas 48 intrinsic brightness 48 faint galaxies 48 galactic mergers 48 CoRoT satellite 48 VLTI 48 ESO VLT 48 interstellar boundary 48 TRMM satellite 48 photometry 48 thundersnow 48 BP Psc 48 prominences 48 sky darkens 48 CoRoT 9b 48 Hawking radiation 48 cosmic microwave radiation 48 absorbs photons 48 Espenak 48 WIMPs 48 perihelion 48 retrograde orbit 48 icy moons 48 ionized gas 48 UVIS 48 starquakes 48 ESA Integral 48 Saturnian 48 nebulas 48 gravitational wave 48 ringed planet 47 vorticity 47 planets 47 cluster NGC 47 axions 47 Madden Julian Oscillation 47 interferometry 47 astronomical phenomena 47 sunlike stars 47 Maunder minimum 47 zodiacal dust 47 Geminid Meteor Shower 47 Keck telescope 47 Sombrero Galaxy 47 Higgs bosons 47 meteor streaked across 47 Tornadic 47 ultraviolet imaging spectrograph 47 planet orbiting 47 galaxy cluster 47 Meteor Showers 47 Supernova #A 47 SIRTF 47 meteoroid 47 highly elliptical orbits 47 Epsilon Eridani 47 galactic magnetic 47 Comet Hartley 47 partial lunar eclipse 47 teleconnections 47 chromosphere 47 solar irradiance 47 Type Ic supernova 47 giant elliptical galaxy 47 protoplanet 47 fissure eruption 47 Type Ia supernovas 47 infrared interferometry 47 Nasa spacecraft 47 Astrophysical 47 potentially habitable planets 47 comets 47 astrometry 47 KBOs 47 jovian 47 gravitational perturbations 47 Spectrograph 47 de Pater 47 Explosive eruptions 47 J# +# [002] 47 Kuiper belt 47 Telescope BAT 47 Gaensler 47 GJ#b 47 infall 47 Wolszczan 47 galactic disk 47 sunrises 47 meteoroids 47 astronomical observations 47 celestial phenomena 47 planetary atmospheres 47 retrograde orbits 47 GQ Lupi 47 total solar eclipse 47 skygazers 47 neutron stars 47 heliopause 47 polar latitudes 47 periodic dimming 47 waning gibbous 47 Swift Tuttle 47 mesosphere 47 NASA Cassini spacecraft 47 constellation Pisces 47 luminous galaxies 47 distant quasars 47 Orionid meteors 47 Hubble observations 47 Gamma ray 47 vortices 47 supergiant stars 47 Particle acceleration 47 geomagnetic field 47 solar minima 47 GRB #A 47 Rydberg atom 47 visible wavelengths 47 V# Mon 47 partial eclipse 47 El Niños 47 shadowed craters 47 Fomalhaut 47 MG J# +# 47 electromagnetic flux 47 UVOT 47 coronagraph 47 permanently shadowed regions 47 muon neutrinos 47 spacecraft flyby 47 emit X rays 47 microlensing 47 Arabia Terra 47 supernovas 47 antineutrinos 47 temperature inversion 47 Mercury exosphere 47 supernova explosion 47 comet tail 47 Super Earths 47 volcano erupting 47 LASCO imagery 47 Eagle Nebula 47 galaxies 47 ESO telescope 47 Milky Way Galaxy 47 masers 47 equinox 47 AB Aurigae 47 HiRISE image 47 quark gluon plasma 47 Cherenkov radiation 47 shorter wavelengths 47 cirrus cloud 47 coronal heating 47 cosmic rays 47 Comet Encke 47 equatorial latitudes 47 Omega Nebula 47 protoplanetary disks 47 intracluster 47 advection 47 brightnesses 47 Amateur astronomers 47 Sromovsky 47 infrared 47 Orionid Meteor Shower 47 HL Tau 47 accretion disks 47 magnetic polarity 47 earthlike planets 47 Saturn moon Mimas 46 telescope 46 Giovanni Cassini 46 weak gravitational lensing 46 spicules 46 Type Ia supernova 46 moonlet 46 distant supernovae 46 volcanic activity 46 Betelgeuse 46 planets orbiting distant 46 Aurora Australis 46 Cepheid variables 46 constellations Cygnus 46 Oscillations 46 Earthlike planet 46 Veil Nebula 46 waxing crescent 46 northern latitudes 46 nova 46 Cassini imaging 46 interacting galaxies 46 Observatory telescope 46 Olympus Mons 46 active galactic nucleus 46 Astronomy 46 NASA QuikScat satellite 46 exoplanet 46 muon neutrino 46 coronal mass ejections CMEs 46 RS Oph 46 CoRoT 46 distant galaxy clusters 46 distant quasar 46 coronal hole 46 Kuiper Belt Object 46 Lake Myvatn 46 N. Rathnasree 46 Tempel Tuttle 46 RY Sagittarii 46 star Fomalhaut 46 Oceanus Procellarum 46 gamma ray bursts GRBs 46 Taurid meteor shower 46 supernova explosions 46 Geminga 46 Astrophysics MOA 46 comets orbiting 46 southerly latitudes 46 waning crescent Moon 46 Grímsvötn 46 penumbral lunar eclipse 46 planetary magnetospheres 46 globulars 46 infrared spectrograph 46 Supernovae 46 Muchachos Observatory 46 Quadrantid 46 Gemini telescopes 46 equator 46 Algol 46 type Ia supernovae 46 Corona Australis 46 Martian polar 46 starlike 46 magnetic substorms 46 spherically symmetric 46 TrES 46 Veniaminof 46 Elenin 46 Valles Marineris 46 Solar flares 46 soliton 46 golden crowned kinglet 46 geoeffective 46 Kuiper Belt object 46 moonquakes 46 ESO PR 46 Butterfly Nebula 46 brown dwarf 46 olivine mineral 46 Saturn Cassini 46 prograde 46 Type 1a supernovae 46 southern latitudes 46 phosphorescence 46 planets orbiting 46 zodiac constellations 46 anticyclonic 46 Cassini 46 Dumbbell Nebula 46 moons orbiting 46 Doppler shift 46 tropopause 46 phonon 46 planet magnetosphere 46 Relations Observatory STEREO 46 meridional 46 astrophysicists 46 Cassini spacecraft orbiting 46 Planck satellite 46 Rayleigh scattering 46 infrared satellite imagery 46 Kepler #b 46 reionization 46 FUV 46 photocurrent 46 brightest supernova 46 submillimeter 46 El Nino Southern Oscillation 46 meteor streaking 46 Heliospheric Observatory 46 planet HD #b 46 Samuel Oschin Telescope 46 GJ #b [001] 46 Optical Gravitational Lensing Experiment 46 circularly polarized light 46 IBEX spacecraft 46 El Niño La Niña 46 phytoplankton blooms 46 distant supernovas 46 #P/Holmes 46 planets comets 46 maxima 46 cumulus cloud 46 atmospheric convection 46 spews ash 46 Corona Borealis 46 brightest comet 46 planetary Transits 46 starburst 46 rocky planets 46 Siding Spring 46 protons collide 46 Comet #P/Holmes 46 Jenniskens 46 LORRI 46 Saturnian moon Titan 46 exo planets 46 millisecond pulsars 46 Keck telescopes 46 interstellar cloud 46 planet orbits 46 moon Mimas 46 Astronomical Society 46 arcsecond 46 helium atoms 46 HiRISE 46 gamma ray flashes 46 Substorms 46 stratovolcano 46 ESA XMM Newton 46 gravitational wobble 46 stargazer 46 magnetic monopoles 46 filamentary structures 46 sidereal 46 bosonic 46 planemos 46 constellation Carina 46 solunar 46 exoplanet orbiting 46 radiotelescope 46 tropical latitudes 46 dust devils 46 constellation Aquila 46 NASA CloudSat 46 mesocyclone 46 NASA STEREO 45 celestial 45 Dennis Mammana 45 Fermi Gamma ray 45 Coma Cluster 45 convection 45 SOAR telescope 45 gamma ray emitting 45 exoplanets planets outside 45 WHIM 45 Halley Comet 45 blue supergiant 45 rayed crater 45 Oort cloud 45 Coma Berenices 45 spiral galaxies 45 pulsar 45 galactic bulge 45 PKS #-# 45 heliospheric 45 exoplanetary systems 45 Milky Way 45 Planck telescope 45 Saturn Enceladus 45 Vassilis Angelopoulos 45 Astrophysicists 45 smallest exoplanet 45 planets circling 45 cirrus clouds 45 ultracold atoms 45 axial tilt 45 solar eclipse 45 carbonate minerals 45 Beehive Cluster 45 millisecond pulsar 45 gamma rays 45 X ray observatories 45 HD #b [001] 45 Serpens Cauda 45 merging galaxies 45 sonoluminescence 45 infalling 45 spookfish 45 spectroscopic observations 45 towering cumulus clouds 45 emits X rays 45 quantum mechanically 45 constellation Hercules 45 astrophotographer 45 Mott insulator 45 ESO Paranal Observatory 45 HiRISE camera aboard 45 globular clusters 45 YORP effect 45 Milky Way galaxy 45 astrophysical phenomena 45 Astronomers 45 Orion Belt 45 planet transits 45 attosecond 45 supervolcanoes 45 permanently shadowed craters 45 azimuthal 45 System #L 45 THEMIS mission 45 MARSIS 45 altocumulus 45 Saturn equinox 45 XMM Newton observations 45 magma chambers 45 circumstellar disks 45 astrophysical objects 45 diffraction patterns 45 orbiting planets 45 rotating neutron stars 45 Ultraviolet Optical Telescope 45 Perseid showers 45 CMB photons 45 Carina Nebula 45 infrared imagery 45 Type Ia 45 diffract 45 galaxies collide 45 Planitia 45 midlatitude 45 wavelengths 45 Wilkinson Microwave Anisotropy Probe 45 galaxy M# [001] 45 Jovian moon 45 Jonathan Lunine 45 THEMIS satellites 45 AU Mic 45 airmass 45 upwelling 45 ULIRGs 45 gamma ray 45 Exoplanet 45 MODIS 45 Telescope 45 Earthshine 45 Infrared Thermal Imaging Spectrometer 45 Subaru Telescope 45 subatomic particle 45 corona 45 insolation 45 Comet 9P/Tempel 1 45 colliding galaxies 45 IR wavelengths 45 volcanoes erupt 45 Vourlidas 45 Hawking Radiation 45 electron neutrino 45 undersea volcanoes 45 nebular 45 Candor Chasma 45 Gravitational lensing 45 cometary 45 electron flux 45 umbra 45 geoneutrinos 45 Very Large Array 45 Subaru telescope 45 austral summer 45 SDSS II 45 Submillimeter Array 45 flood basalts 45 millimeter wavelengths 45 zodiacal constellations 45 Orientale Basin 45 Cabeus 45 constellations planets 45 protoplanetary disk 45 Arches Cluster 45 cosmic cannibal 45 Type Ia supernovae 45 precession 45 velocity dispersion 45 crescent Moon 45 ITCZ 45 ESA Herschel 45 ionized particles 45 energetic gamma rays 45 VISTA telescope 45 Bose Einstein condensates 45 Iapetus 45 Aurigae 45 planets moons 45 Pegasi 45 perigee 45 water vapor 45 galaxies nebulae 45 moonlets 45 emitted photons 45 anisotropy 45 lensing galaxy 45 Wolf Rayet stars 45 Jovian moons 45 infrared spectra 45 asteroidal 45 Imaging Spectroradiometer MODIS instrument 45 galaxy formation 45 tau neutrinos 45 glows orange 45 Infrared Mapping Spectrometer VIMS 45 Astrophysical Journal Letters 45 AKARI 45 constellation Eridanus 45 Solar TErrestrial RElations Observatory 45 cosmic ray particles 45 faint glow 45 SuperMoon 45 supermassive black hole 45 sulfate aerosols 45 Voyager spacecraft 45 GROND 45 Kitt Peak 45 dust enshrouded 45 SeaWiFS 44 NASA Wilkinson Microwave 44 La Silla Chile 44 Lunar eclipses 44 unpolarized 44 gravitational lenses 44 Astrophysics Cambridge Mass. 44 Carey Lisse 44 Sedna 44 Mariana Arc 44 refracts light 44 X ray observatory