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(Click for frequent words.) 71 asteroid 70 asteroid Apophis 68 Apophis asteroid 67 MN4 66 # Apophis 65 RQ# 61 asteroids 60 YU# 59 Asteroid 59 meteoroid 55 WD5 55 orbital debris 54 Toutatis 54 QQ# 54 comet 53 Pluto Charon 53 satellites orbiting Earth 53 Phobos 53 NEAs 53 gravitational keyhole 52 NEOs 52 Comet Tempel 1 52 impactor 52 TU# [002] 51 asteroid Itokawa 51 impactors 51 ESA Rosetta 51 Kuiper Belt object 51 meteoroids 51 micrometeoroids 51 Nibiru 51 gaseous planet 51 comet nucleus 51 Gliese #c 51 Halley comet 51 Earth asteroids 51 meteor 50 Churyumov Gerasimenko 50 Earth Object 50 Lutetia 50 New Horizons spacecraft 50 Oort Cloud 50 planet Uranus 50 Asteroid Itokawa 50 spacecraft 50 Itokawa 50 detect gravitational waves 50 Cassini Huygens 50 Tunguska 50 Corot 7b 49 Spaceguard Survey 49 Timothy Spahr 49 celestial object 49 COROT 49 comet Shoemaker Levy 49 Comet Hartley 49 meteorite 49 Tunguska asteroid 49 Saturn rings 49 Comet Churyumov Gerasimenko 49 asteroid Steins 49 Spaceguard 49 protoplanet 49 micrometeoroid 49 Mars Odyssey spacecraft 49 GA6 48 Kuiper Belt Object 48 planetoid 48 cosmic ray 48 Boslough 48 orbital velocity 48 BepiColombo 48 OSIRIS REx 48 Tunguska object 48 Sasselov 48 moons Phobos 48 Voyager spacecraft 48 Pluto Eris 48 COROT exo 3b 48 orbiting 48 Viking Lander 47 comets 47 Cassini Huygens spacecraft 47 orbiter 47 Comet #P/Churyumov-Gerasimenko 47 smallest exoplanet 47 Comet Hartley 2 47 Cancri e 47 Methone 47 unmanned spacecraft 47 P/# A2 47 EPOXI spacecraft 47 Antenna LISA 47 Cassini 47 Titan flyby 47 LCROSS spacecraft 47 Yarkovsky effect 47 Chicxulub 47 distant galaxy 47 Elenin 47 Higgs particle 47 APXS 47 asteroid Lutetia 47 tiny meteoroid 47 Kepler 9c 47 Kepler #b 47 KBOs 47 Nasa spacecraft 47 Tunguska meteorite 47 cosmic collisions 47 satellites orbiting 46 extraterrestrial civilization 46 comet dust 46 Comet Elenin 46 orbits 46 SIM PlanetQuest 46 GJ #b [001] 46 Gerard Kuiper 46 Halley Comet 46 comet Tempel 1 46 orbit 46 Antennae Galaxies 46 Tunguska Siberia 46 Saturn outermost moon 46 WASP #b 46 galactic clusters 46 NASA Stardust spacecraft 46 Martian rover 46 Tempel 1 46 lunar crater 46 Red Planet 46 Lunar Prospector 46 SuitSat 46 lunar perigee 46 comet #P/Churyumov-Gerasimenko 46 Oort cloud 46 Ring Nebula 46 asteroid impacts 46 perigee 46 foam fragment 46 retrograde orbit 46 spacecrafts 46 Reconnaissance Orbiter 46 Stardust spacecraft 46 GRB #B 46 comet Wild 46 LADEE 46 Earthlike planet 46 bolide 46 magnetar 46 TrES 4 46 flyby spacecraft 46 Sedna 46 #P/Churyumov-Gerasimenko 46 OGLE TR 45 Phobos Grunt 45 Comet Lulin 45 perihelion 45 GJ#b 45 planet TrES 45 outer planets 45 polar orbit 45 Earth radii 45 colliding asteroids 45 HD#b 45 MUSES C 45 elliptical orbit 45 Solar Orbiter 45 asteroid collisions 45 orbiting satellites 45 moonlet 45 Jenniskens 45 Martian meteorites 45 Quaoar 45 Mars Reconnaissance Orbiter MRO 45 planetoids 45 innermost planet 45 gravitational lens 45 Zolotukhin 45 microlensing events 45 astronomer Johannes Kepler 45 Deep Impact probe 45 LCROSS 45 gravitational wave 45 Itokawa asteroid 45 exo planets 45 Martian dust 45 VD# [001] 45 Torino Scale 45 Earth Asteroid 45 Enceladus flybys 45 Messenger spacecraft 45 astronomers 45 Gliese #g 45 Lunar Reconnaissance Orbiter LRO 45 comet Wirtanen 45 CoRoT 45 Lunokhod 45 outermost planets 45 geostationary orbits 45 Galileo spacecraft 45 SMOS mission 45 Kuiper belt object 45 trans Neptunian objects 45 comet Churyumov Gerasimenko 45 asteroid orbit 45 Cryosat 45 Deep Impact comet 45 Terrestrial Planet Finder 45 S/# P2 45 Deep Impact craft 45 NROL 45 comets meteors 45 comet particles 45 X ray observatory 45 navigate autonomously 44 extraterrestrial civilizations 44 Comet Halley 44 Epsilon Eridani 44 radial velocity 44 Chicxulub crater 44 Cabeus 44 Victoria Crater 44 GeV 44 planet Nibiru 44 Higgs Boson 44 microlensing 44 MIT planetary scientist 44 heliopause 44 interplanetary spacecraft 44 Kuiper Belt objects 44 Asteroid Apophis 44 Beta Pictoris b 44 moons orbiting 44 unmanned probes 44 Tunguska Event 44 Opportunity rover 44 observable universe 44 NASA Kepler 44 asteroid flyby 44 orbiting Hubble Space Telescope 44 impactor spacecraft 44 closest flyby 44 constellation Sagittarius 44 lander 44 COROT 7b 44 Fomalhaut b 44 celestial bodies 44 Rosetta spacecraft 44 Earthlike planets 44 planets 44 orbiting spacecraft 44 extrasolar planets 44 habitable planets 44 ringed planet 44 icy comets 44 orbital resonance 44 aphelion 44 Chodas 44 exoplanetary 44 Quadrantids 44 robotic spacecraft 44 asteroid Eros 44 interstellar dust particles 44 cosmic particles 44 Convection Rotation 44 icy moons 44 Higgs boson particle 44 manned lunar mission 44 Higgs bosons 44 meteorites 44 Comet Shoemaker Levy 44 dwarf planet 44 Upsilon Andromedae b 44 Kuiper belt 44 gravitational waves 43 Jupiter icy moons 43 Mars Odyssey 43 GOCE satellite 43 Saturnian moons 43 GJ #b [002] 43 Uranus 43 Jovian moon 43 Galilean moons 43 Eta Carinae 43 six wheeled rover 43 Gliese #d 43 KT extinction 43 arcseconds 43 NASA Voyager spacecraft 43 transiting planet 43 exoplanets orbiting 43 UB# [003] 43 coronal mass ejection 43 Saturn Cassini 43 Sojourner rover 43 Steins asteroid 43 spherules 43 comet McNaught 43 Cassini flyby 43 Kepler spacecraft 43 exosolar planets 43 Voyager probes 43 gravitationally bound 43 Hale Bopp 43 S/# S1 43 Laser Interferometer Space 43 Gliese #e 43 Martian surface 43 SIRTF 43 Kuiper belt objects 43 geoneutrinos 43 Centaur rocket 43 Kepler Mission 43 Yinghuo 1 43 Earth magnetosphere 43 Nasa 43 Higgs boson 43 interstellar particles 43 cometary 43 millisecond pulsar 43 Kuiper Belt Objects 43 Giovanni Cassini 43 galaxy M# [001] 43 Comet Hale Bopp 43 Giove B 43 Omega Centauri 43 extrasolar planet 43 cosmic ray collisions 43 Shoemaker Levy 43 distant quasar 43 Andromeda 43 bipod ramp 43 rocky extrasolar planet 43 inhabitable planets 43 rover 43 moon Deimos 43 ESA ASI 43 star Gliese 43 orbiting telescope 43 Grillmair 43 Earth objects NEOs 43 Martian atmosphere 43 Gravity Probe B 43 Prof Pillinger 43 Nasa Jet Propulsion 43 sols 43 Martian rocks 43 micrometeorite 43 Mandushev 43 planetary Transits 43 elusive Higgs boson 43 micrometeorites 43 Mars 43 Lake Cheko 43 AAVSO 43 martian atmosphere 43 Planck satellite 43 cosmic cannibal 43 Shackleton crater 43 gravitational microlensing 43 telescopic observations 43 particle smasher 42 periodic dimming 42 asteroid Vesta 42 astrobiological 42 Milky Way Galaxy 42 plutoids 42 Earth orbit 42 noctilucent clouds 42 Interior Laboratory GRAIL 42 protoplanets 42 Gamma ray burst 42 Andromeda Galaxy 42 moonlets 42 XP# [004] 42 neighboring Andromeda galaxy 42 Phaethon 42 Tunguska explosion 42 RHESSI 42 galactic alignment 42 solar flares 42 Bullet Cluster 42 Infrared Pathfinder Satellite 42 ESA SMART 42 NASA EPOXI mission 42 exoplanets 42 NASA Cassini spacecraft 42 Jupiter moons 42 spacecraft thrusters 42 RX# [003] 42 rover Sojourner 42 asteroid belt 42 NASA LCROSS 42 magnetic monopole 42 Galilean satellites 42 Mars Pathfinder 42 thermal emission spectrometer 42 mu Arae 42 Jupiter Icy Moons 42 microquasar 42 Hubble Telescope 42 Chicxulub Crater 42 copper impactor 42 spacecraft orbiting 42 Sensing Satellite LCROSS 42 rock outcrop 42 ExoMars 42 orbiting observatories 42 Fermi telescope 42 planetary orbits 42 Samuel Oschin Telescope 42 journal Meteoritics 42 highly elliptical orbit 42 Mini TES 42 lunar surface 42 Deep Impact flyby spacecraft 42 Haumea 42 Swift Tuttle 42 gamma ray burst 42 ALH# 42 comet tail 42 interstellar dust 42 subatomic particle 42 ExoMars rover 42 International Linear Collider 42 Plait 42 antiproton 42 celestial mechanics 42 antihelium 42 NASA Kepler telescope 42 JIMO 42 dwarf galaxy 42 comet Boethin 42 CoRoT 7b 42 comets asteroids 42 Meteor Crater 42 baryon 42 Saturn moons 42 Ranging MESSENGER spacecraft 42 supersymmetric particles 42 Chang'eI 42 Goldilocks planet 42 flyby 42 Andromeda galaxy 42 elliptical orbits 42 lunar meteorites 42 CALIPSO 42 HiRISE image 42 retrograde orbits 42 Bad Astronomy 42 Hubble observations 42 comet chaser 42 S/# [001] 42 radial velocity method 42 Krimigis 42 galaxy M# [002] 42 rover Opportunity 42 Saturn moon 42 asteroidal 42 NASAs 42 rover Spirit 42 infrared telescope 42 stellar occultation 42 Mars Phobos 42 moon Enceladus 42 Solar Terrestrial Relations 42 Mars moon Phobos 42 Uranian 42 Martian crater 42 Hubble Space Telescope HST 42 JAXA 42 asteroids orbiting 42 orbital eccentricity 42 lander Beagle 2 42 lunar orbit 42 irregularly shaped asteroid 42 Orbiter 42 cometary dust 42 geosynchronous satellites 42 GRB # 41 SOHO spacecraft 41 Proba 2 41 LHC experiments 41 comet orbit 41 orbiting Hubble telescope 41 robotic explorer 41 NASA Deep Impact 41 Ofeq 41 Hubble telescope 41 spokesman Michael Braukus 41 Epsilon Aurigae 41 Lulin 41 NFIRE 41 NASA 41 planets orbits 41 Jupiter moon Io 41 God Particle 41 TGFs 41 cosmic rays 41 Epoxi 41 star Proxima Centauri 41 exoplanet hunter 41 Pluto 41 planets Kepler 41 Orionids 41 Huygens Probe 41 Asteroids 41 Ranging spacecraft 41 SUSY 41 extrasolar planetary systems 41 Hipparcos 41 LightSail 41 Cosmic ray 41 Sumatran earthquake 41 Mars rovers 41 occultations 41 orbital rendezvous 41 Earth Asteroid Rendezvous 41 Hubble 41 Asteroid Belt 41 Crab Pulsar 41 neutrino 41 lunar orbiter 41 plutoid 41 Triangulum 41 supernova explosion 41 Kuiper Belt 41 HD #b [001] 41 SpaceX Falcon 41 Voorwerp 41 antimatter particles 41 spacecraft Cassini 41 GT9 41 Huygens 41 stony meteorites 41 Orionid 41 Comet Machholz 41 Don Yeomans 41 Emily Lakdawalla 41 SN #A 41 circumlunar satellite 41 comet Lulin 41 Einstein theory 41 reentry capsule 41 YORP effect 41 Orbiting Carbon Observatory 41 Union IAU 41 nanosatellite 41 supermoon 41 NASA rovers 41 airbursts 41 meteors 41 orbiters 41 Tevatron experiments 41 Planetary Transits 41 Schweickart 41 Gusev crater 41 Epimetheus 41 orbit GEO 41 Galileo satellites 41 BLG #Lb 41 orbiting Mars 41 Jovian moons 41 Leonids 41 GOCE 41 XMM Newton 41 Rosetta lander 41 permanently shadowed crater 41 Lunar Crater 41 Mission TRMM satellite 41 Avishay Gal Yam 41 Venusian 41 Orbiter LRO 41 Martian rovers 41 Fomalhaut 41 moons orbiting Saturn 41 CloudSat 41 strangelets 41 crewed spacecraft 41 planets circling 41 geomagnetic storms 41 Drake Equation 41 Optical Gravitational Lensing Experiment 41 Earth 41 amateur skywatchers 41 planemos 41 Chandrayan 41 Jodrell Bank 41 International Astronomical 41 J# +# [002] 41 Rover Opportunity 41 astrometric 41 electron volts 41 extraterrestrial 41 Hayabusa 41 MErcury Surface Space ENvironment 41 Orbiting 41 HAT P 41 Wolszczan 41 inner Oort Cloud 41 GALEX 41 Kepler observatory 41 planets Uranus 41 HD #b [002] 41 orbited Jupiter 41 occultation 41 Gliese 41 Einstein relativity theory 41 geo stationary orbit 41 magnetars 41 Mossbauer spectrometer 41 elongated orbits 41 SMEX 41 Yakushin 41 geoid 41 particle beam 41 gravitational lenses 40 Dwarf Planet 40 GRBs 40 KT boundary 40 NASA Mars Odyssey 40 sterile neutrino 40 cometary debris 40 Charon Pluto 40 Mars Lander 40 NASA Cassini 40 collider 40 alien civilizations 40 Meteoritics 40 whiz harmlessly 40 interstellar dust grains 40 planets orbiting 40 cosmic strings 40 Higgs Boson particle 40 NuSTAR 40 planets orbiting distant 40 agency Roskosmos 40 Ariane rocket 40 Hubble servicing 40 Sara Seager 40 HiRISE camera aboard 40 Enceladus 40 boson 40 equatorial orbit 40 geosynchronous 40 Venusian surface 40 Mini SAR 40 rovers 40 Nili Fossae 40 Soviet cosmonaut Yuri Gagarin 40 tiny meteoroids 40 globular clusters 40 SN #C 40 extraterrestial 40 MESSENGER 40 geomagnetic activity 40 GOSAT 40 Mars orbiting spacecraft 40 GEochemistry 40 Baptistina 40 Lunar CRater Observation 40 meteoritic material 40 orbiting Kepler telescope 40 pulsar 40 Geminids 40 NOAA GOES 40 Fermi Paradox 40 hypervelocity star 40 geomagnetic storm 40 moon Titan 40 Maria Zuber 40 planet orbiting 40 Mini Thermal Emission 40 Saturnian 40 moonquakes 40 hypervelocity stars 40 arcminutes 40 Earthlings 40 Cabeus crater 40 planetesimals 40 extrasolar planets orbiting 40 albedo reflectivity 40 Kosmos 3M rocket 40 gravitational slingshot 40 Late Heavy Bombardment 40 OSIRIS Rex 40 EarthCARE 40 jovian 40 Manned missions 40 THEMIS Images 40 Supermoon 40 Cosmonaut Yuri Gagarin 40 comet Hartley 2 40 Isidis Planitia 40 Borexino 40 Huygens lander 40 ejecta blanket 40 extraterrestrial origin 40 Deep Impact mission 40 astrometry 40 astronomical phenomena 40 galactic cosmic rays 40 Laser Interferometer Gravitational Wave 40 Lunar Orbit 40 origins spectrograph 40 orbiting Saturn 40 Saturnian moon Titan 40 Comet McNaught 40 planets orbiting sun 40 Pan STARRS 40 HiRISE 40 sidereal 40 Mars Squyres 40 ejecta 40 ultraluminous galaxy 40 Martian orbit 40 Tevatron collider 40 unmanned rover 40 robot rovers 40 Discovery undocks 40 NASA MESSENGER 40 Earths 40 cosmic 40 Bonneville Crater 40 Comet Boethin 40 gamma ray observatory 40 super Earths 40 ellipse 40 martian 40 spiral nebulae 40 superheavy elements 40 conventional warhead 40 twin Voyager spacecraft 40 cosmic radiation 40 highly elliptical orbits 40 NASA Stratospheric Observatory 40 Earth asteroid Itokawa 40 Erik Asphaug 40 probe Chang'e 40 twin rover Opportunity 40 Hayabusa probe 40 dustier stormier atmosphere 40 dimming starlight 40 Saturnian system 40 cosmological observations 40 Cosmologists 40 moon permanently shadowed 40 muons 40 Cassini spacecraft 40 Saturn moon Mimas 40 Philae 40 intercontinental missile 40 Lake Vostok 40 Gamburtsev 40 Exoplanet 40 dwarf galaxies 40 hydrostatic equilibrium 40 celestial sphere 40 Macroscale Interactions during 40 Flyby spacecraft 40 lunar poles 40 Rosetta orbiter 40 energetic cosmic rays 40 onboard Chandrayaan 40 Einstein theories 40 planet Gliese #g 40 MARSIS 40 Gondolo 40 Envisat 40 transiting planets 40 arcsecond 40 lunar orbiter Chang'e 40 moon Charon 40 astrophysicists 40 LCROSS mission 40 Higgs singlet 39 Ed Weiler NASA 39 hypersonic glider 39 Tycho Brahe 39 Deep Impact spacecraft 39 exo planet 39 Delta Cephei 39 proton proton collisions 39 smallest extrasolar planet 39 Hubble Space Telescope 39 WISE spacecraft 39 Aqua satellite 39 Hubble Space telescope 39 Mercury flyby 39 circular orbit 39 ETs 39 Climate Experiment GRACE 39 ICBMS 39 CryoSat satellite 39 Murchison meteorite 39 sized planets orbiting 39 carbonaceous chondrite 39 CryoSat mission 39 super perigee moon 39 Cryospheric Sciences Branch 39 planet WASP #b 39 Upsilon Andromedae 39 Hayabusa capsule 39 Orbiter MRO 39 cometary material 39 Meteorites 39 NASA CloudSat 39 particle detector 39 EPOXI 39 NASA Kepler spacecraft 39 Soyuz Fregat launcher 39 asteroids comets 39 PSR J# 39 Zecharia Sitchin 39 extragalactic 39 Supernova #A 39 apogee farthest point 39 NanoSail D 39 constellation Virgo 39 substorms 39 nebular 39 MESSENGER spacecraft 39 muon 39 Sensing Satellite 39 Chandrayaan 39 geo synchronous orbit 39 INSAT 4CR 39 Discovery liftoff 39 Martian equator 39 Boethin 39 robotic rovers 39 TRMM satellite 39 gravitational lensing 39 planet transits 39 ICBM 39 binary asteroid 39 spaceplane 39 Mars Odyssey orbiter 39 Explorer WISE 39 Delfi C3 39 Deep Impact 39 Hayabusa spacecraft 39 LAGEOS 39 martian meteorites 39 sunspot cycle 39 supervolcanoes 39 merging galaxies 39 electromagnetic signals 39 Express orbiter 39 planetary embryos 39 hypervelocity 39 general relativity 39 Sun synchronous orbit 39 rocky planets 39 Henize #-# 39 wrinkle ridges 39 WIMPs 39 Neukum 39 TanDEM X 39 Comet 9P/Tempel 1 39 spiral galaxy NGC 39 AB Aurigae 39 Kiruna Sweden 39 NEOSSat 39 SuperMoon 39 OGLE 39 spacecraft flyby 39 astrophysical phenomena 39 globular cluster 39 Cygnus X 39 Cosmic Microwave Background 39 NASA Lunar Crater 39 Venus transits 39 moon Mab 39 orbiting gamma ray 39 Nasa Kepler 39 Loop Current 39 satellites 39 CoRoT #b 39 Optical Spectroscopic 39 Nasa Deep Impact 39 CERN LHC 39 geosynchronous orbit 39 Sumatra Andaman earthquake 39 eclipsing binary 39 exoplanetary systems 39 lander rover 39 panspermia 39 WISE infrared 39 Makemake 39 Martian 39 Reflection Radiometer 39 decadal survey 39 PSLV C6 39 GZK cutoff 39 protons 39 Small Body Nomenclature 39 manned lunar 39 NASA THEMIS 39 Hyakutake 39 magnetosphere 39 spacetime 39 Anaxagoras 39 ionosphere 39 Mars Reconnaissance Orbiter 39 planetary surfaces 39 extrasolar planetary 39 TrES 39 STSS Demo 39 lunar landing 39 MAVEN 39 quasar 39 YES2 39 demoting Pluto 39 polar orbits 39 NASA rovers Spirit 39 Edmund Halley 39 incoming ballistic missiles 39 intrinsic brightness 39 constellation Lyra 39 DIXI 39 orbiting observatory 39 ADM Aeolus 39 Saturn moon Enceladus 39 gravitational redshift 39 extraterrestrials 39 strangelet 39 telescopes astronomers 39 constellation Cassiopeia 39 heavily cratered 39 Comet #P 39 crater Cabeus 39 lunar orbits 39 Kepler Telescope 39 orbital inclination 39 Extremely Large Telescope 39 THEMIS 39 Martian arctic plains 39 radial velocities 39 Ikaros 39 distant supernovae 39 eclipsing binaries 39 Cloud Aerosol Lidar 39 Proxima Centauri 39 Odyssey orbiter 39 binary asteroids 39 CoRoT satellite 39 Chandrayaan II 39 Gaia Hypothesis 39 Super Earths 39 twin STEREO spacecraft 39 planetary astronomer 39 Cometary 39 moon Iapetus 39 Sputnik satellite 39 radial velocity technique 39 SN #gy 39 terrestrial planets 39 Kepler Space Telescope 39 Hurricane Dean 39 Konstantin Tsiolkovsky 39 geostationary satellite 39 Shenzhou V 39 Foton M3 39 Global Surveyor 39 Ulysses spacecraft 39 smoothest flattest spot 39 cosmic gamma rays 39 infrared observatory 39 Philae lander 39 NASA MESSENGER spacecraft 39 cosmic ray particles 39 Corot 9b 39 GLONASS satellites 39 probe Akatsuki 39 brown dwarfs 39 Spacewatch 39 GQ Lupi 39 Johannes Kepler 39 Tegmark 39 rotational axis 38 exoplanet 38 Regolith 38 NASA twin rovers 38 meteorological satellites 38 quantum particle 38 Phil Plait 38 Cartosat 2B 38 constellation Serpens 38 particle colliders 38 planet Gliese #c 38 Virgo Cluster 38 Huygens descent 38 Roswell UFO 38 swingby 38 Nicolaus Copernicus 38 Hipparchus 38 antiparticle