Related by context. Frequent words. (Click for all words.) 76 exoplanets 75 galaxies 75 extrasolar planets 73 comets 72 galaxy 70 celestial bodies 70 Milky Way galaxy 70 supernovae 69 asteroids 68 planetary 68 Solar System 67 exoplanet 67 distant galaxies 67 moons 66 Milky Way 66 quasars 65 orbits 65 Earths 65 comet 64 Kuiper Belt 64 Uranus 64 astronomers 63 supernova 63 neutron star 63 planet 63 supermassive black holes 63 neutron stars 63 brown dwarf 63 cosmos 62 pulsars 62 universe 62 Enceladus 62 Saturn rings 61 nebula 61 asteroid 60 gamma ray bursts 60 galactic 60 asteroid belt 60 quasar 59 Pluto 59 habitable zone 59 Astronomers 59 Planets 58 pulsar 58 cosmic 58 orbiting 58 Earth 57 constellations 57 neutrinos 57 atoms 57 Saturn moon 56 Galaxies 56 suns 56 solar flares 55 cosmic rays 55 Mars 55 organic molecules 55 sunspots 55 meteorites 55 Spitzer Space Telescope 54 interstellar 54 astrophysicists 53 celestial 53 magnetic fields 53 Martian surface 53 Universe 53 Red Planet 53 fainter 52 Kepler 52 hydrogen atoms 52 Martian 52 subatomic particles 52 lunar surface 51 nuclei 51 meteors 51 martian 51 cosmological 51 gamma rays 51 neutrons 51 Cassini 50 Martian atmosphere 50 Asteroids 50 gravitational 50 general relativity 50 astronomer 50 Andromeda 50 dwarf planet 50 Planck 49 universes 49 antimatter 49 equator 49 vortices 49 orbital 49 telescopes 48 moon 48 Einstein theory 48 outer space 48 corona 48 extraterrestrial 48 MESSENGER 48 filaments