Related by context. Frequent words. (Click for all words.) 76 rocky planets 72 terrestrial planets 71 habitable zone 66 moon Europa 65 planets 65 brown dwarfs 63 planets orbiting 61 brown dwarf 60 Earth asteroids 59 Milky Way galaxy 59 extrasolar planets 59 HD #b [002] 58 planet orbiting 58 elliptical galaxies 58 Milky Way Galaxy 57 exoplanets 57 Saturn moons 57 unaided eye 57 globular clusters 57 Enceladus 57 galaxies 56 dwarf galaxies 56 GRBs 56 distant galaxies 55 nebulae 55 extrasolar planet 55 Jupiter Saturn Uranus 55 spiral galaxies 55 infrared wavelengths 55 Milky Way 54 exoplanet 54 Kuiper Belt 54 supermassive black holes 54 galaxy clusters 54 Gliese 53 orbits 53 supernovae 53 galaxy 53 galaxy cluster 53 quasars 53 heliosphere 52 nebula 52 neutron stars 52 organic molecules 52 supernova explosion 52 distant galaxy 52 Betelgeuse 51 celestial objects 51 neutron star 51 comets 51 Solar System 51 outer planets 51 Earths 51 magnetosphere 51 polar regions 51 Saturn moon 50 supermassive black hole 50 silicates 50 moon Titan 50 gravitational waves 50 Astronomers 50 redshift 50 dwarf planets 50 quasar 50 ejecta 50 mid latitudes 50 supernovas 50 astrophysical 50 gamma ray bursts 49 asteroids 49 Martian surface 49 celestial bodies 49 planet 49 interstellar medium 49 Sedna 49 Saturn rings 48 hydrothermal vents 48 Meridiani Planum 48 astronomers 48 suns 48 convective 48 Spitzer Space Telescope 48 northern latitudes 48 abundances 48 single celled 48 interstellar dust 48 superfluid 48 planetary 48 cosmic microwave background 48 gamma ray burst 48 moons 48 spacetime 47 universe 47 magnetic fields 47 habitability 47 olivine 47 orbiting 47 Iapetus 47 optical telescopes 47 fainter 47 constellations