Related by context. Frequent words. (Click for all words.) 79 galaxies 77 Milky Way galaxy 73 Milky Way 72 planets 71 supernova 71 nebula 70 galactic 70 distant galaxies 69 supernovae 69 neutron star 69 universe 67 supermassive black holes 65 quasars 65 comet 65 quasar 65 Solar System 63 neutron stars 63 planet 62 cosmos 62 asteroid belt 62 pulsar 61 comets 61 gamma ray bursts 61 exoplanet 60 orbits 60 exoplanets 60 Kuiper Belt 60 extrasolar planets 59 asteroids 59 gamma rays 58 Galaxies 58 interstellar 58 cosmic 58 planetary 58 Universe 57 pulsars 56 Uranus 55 orbiting 55 Enceladus 55 asteroid 55 astronomers 55 moons 55 cosmic rays 55 fainter 54 corona 54 Andromeda 54 neutrinos 54 Saturn rings 53 atoms 53 celestial bodies 53 Earths 53 starlight 52 Astronomers 52 Spitzer Space Telescope 52 solar flares 52 gravitational 51 constellation 51 Earth 51 Big Bang 51 astrophysicists 51 nuclei 51 subatomic particles 50 celestial 50 suns 50 magnetic fields 49 outer layers 49 intergalactic 49 gravitational pull 49 orb 49 Tempel 1 48 filaments 48 meteors 48 photons 48 meteor 47 gaseous 47 cosmological 47 neutrons 47 organic molecules 47 luminosity 47 Saturn moon 46 proton 46 Martian surface 46 hydrogen atoms 46 gamma ray 46 spectra 46 Martian atmosphere 46 Galactic 46 ionosphere 46 electrons 46 particles 46 Pluto 46 starship 45 antimatter 45 universes 45 sunspot 45 general relativity 45 Cassini 45 NGC 45 protons 45 Einstein theory 45 impactor