Related by context. Frequent words. (Click for all words.) 66 rocky planets 64 planets 64 Saturn moons 64 HD #b [002] 64 super Earths 63 Kuiper belt 63 Saturn moon 63 planet orbits 63 planets orbiting 62 Andromeda galaxy 62 habitable planet 62 terrestrial planets 61 planet orbiting 61 moon Charon 61 habitable planets 60 hot Jupiters 60 distant galaxy 60 moons 60 galaxy cluster 60 extrasolar planet 60 supernova explosion 59 X ray emission 59 Saturn rings 59 exoplanets 59 extrasolar planets 58 Eta Carinae 58 moon Titan 58 Gliese #g 58 brown dwarf 58 Milky Way galaxy 58 Orion Nebula 58 elliptical galaxies 58 Crab Nebula 58 supernova remnant 58 Mimas 58 Sedna 58 nebulae 58 volcanically active 58 orbits 58 dwarf galaxies 57 Iapetus 57 Saturn moon Enceladus 57 brown dwarfs 57 Large Magellanic Cloud 57 orbiting 57 exoplanet 57 Fomalhaut 57 magnetar 57 Jupiter Saturn Uranus 57 asteroid 57 nebula 56 NASA Cassini spacecraft 56 Spitzer Space Telescope 56 Jupiter moons 56 moon Europa 56 Uranus 56 outer planets 56 accretion disk 56 asteroids 56 galaxy clusters 56 dwarf galaxy 56 Andromeda Galaxy 56 celestial object 56 comet 56 Milky Way Galaxy 56 globular cluster 56 XMM Newton 55 ejecta 55 COROT 55 ringed planet 55 Enceladus 55 Solar System 55 Kuiper Belt 55 GRBs 55 supernova explosions 54 comets 54 X ray Observatory 54 meteoroids 54 spiral galaxy 54 Gliese 54 Betelgeuse 54 pulsar 54 quasar 54 geologically active 54 interstellar medium 54 spiral galaxies 54 galaxies 54 planet 54 gravitationally 54 Alpha Centauri 54 infrared telescope 53 distant galaxies 53 galaxy 53 interstellar dust 53 astronomers 53 astrobiologists 53 gamma ray burst 53 supermassive black holes 53 Opportunity rover 53 Cassini Huygens 53 ionized gas