Related by context. Frequent words. (Click for all words.) 72 galaxies 70 brown dwarf 70 brown dwarfs 70 galaxy 69 quasars 68 neutron star 68 Milky Way galaxy 68 nebula 68 quasar 67 supernovae 67 neutron stars 67 Milky Way 66 spiral galaxy 66 dwarf galaxies 66 supermassive black hole 66 supernova 66 distant galaxy 65 planet orbiting 65 galaxy clusters 64 gamma ray burst 64 nebulae 64 rocky planets 64 planets orbiting 64 gamma ray bursts 63 astronomers 63 pulsars 63 distant galaxies 63 exoplanets 62 exoplanet 62 supermassive black holes 62 redshift 62 astrophysicists 61 planets 61 pulsar 61 supernovas 60 extrasolar planets 59 Kuiper Belt 59 Astronomers 58 XMM Newton 58 Betelgeuse 57 comets 57 orbits 56 X ray Observatory 56 Spitzer Space Telescope 56 galactic 55 astrophysical 55 Sedna 55 cosmic microwave background 55 nuclei 55 Enceladus 55 cosmological 54 celestial objects 54 comet 54 spectra 54 infrared wavelengths 54 Saturn rings 54 gamma rays 54 Gliese 54 gravitational waves 53 cosmologists 53 neutrino 53 Galaxies 53 Cassiopeia 53 spectroscopic 53 asteroid belt 53 UB# [003] 53 asteroid 53 fainter 53 corona 53 orbiting 53 Pleiades 52 GRB 52 positrons 52 cosmic ray 52 atoms 52 habitable zone 52 Solar System 52 moons 52 neutrons 52 WMAP 52 asteroids 52 magnetosphere 51 constellation 51 dynamical 51 Andromeda 51 deuterium 51 subatomic particles 51 neutrinos 51 Very Large Telescope 51 cosmic rays 51 sunspot 51 universe 50 gravitational 50 quark 50 planetary 50 impactor 50 heliosphere 50 Astrophysical Journal 50 Iapetus 49 NASA Chandra 49 magnetic fields