Related by context. Frequent words. (Click for all words.) 46 galaxy 45 Milky Way galaxy 44 Solar System 43 farthest 43 distant galaxies 42 asteroid belt 41 comet 41 galaxies 41 planets 41 planet 40 Milky Way 40 Gliese 39 interstellar space 39 nebula 39 gamma ray burst 39 Sedna 39 planets orbiting 39 exoplanet 39 Saturn rings 39 astronomers 39 exoplanets 39 orbits 38 quasars 38 elliptical orbit 38 Kuiper Belt 38 Hubble telescope 37 redshift 37 moons 37 infrared wavelengths 37 brown dwarfs 37 galaxy clusters 37 fainter 37 miles 37 pulsar 36 extrasolar planets 36 farther 36 supernova 36 gamma ray bursts 36 cosmic microwave background 36 orbiting 36 pulsars 36 supermassive black hole 36 kilometers 36 equator 35 quasar 35 furthest 35 Hubble Telescope 35 Uranus 35 asteroid 35 moon 35 galactic 35 brown dwarf 35 starlight 35 moon Titan 35 Halley Comet 35 neutron star 35 rocky planets 34 comets 34 constellation 34 supernovae 34 Astronomers 34 Tempel 1 34 comet Tempel 1 33 meteor 33 cosmos 33 supernovas 33 asteroids 33 cosmic ray 33 Earth orbit 33 celestial objects 33 neutron stars 33 gamma rays 32 sunspot 32 Earth 32 Martian surface 32 celestial bodies 32 particle accelerator 32 suns 32 cosmologists 32 Enceladus 32 universe 32 supermassive black holes 31 cosmic rays 31 Spitzer Space Telescope 31 Einstein theory 31 astrophysicists 31 meteors 31 earth 31 dwarf planet 31 outer reaches 31 Cassini 31 Pluto 31 reaching 31 km 31 ionosphere 30 impactor 30 Pleiades 30 cosmic 30 corona 30 celestial 30 magnetosphere