Related by context. Frequent words. (Click for all words.) 77 gamma ray burst 67 XMM Newton 67 gamma ray bursts 66 distant galaxy 65 supernova 65 galaxy cluster 65 quasar 64 redshift 63 GRB 62 planet orbiting 62 brown dwarf 62 neutron star 62 supernovae 62 supermassive black hole 61 quasars 61 exoplanet 60 pulsar 60 X ray Observatory 59 distant galaxies 59 galaxies 59 Milky Way Galaxy 59 spiral galaxy 59 galaxy clusters 59 exoplanets 59 globular clusters 58 gamma rays 58 comet 58 pulsars 58 neutron stars 58 gravitational waves 57 extrasolar planets 57 cosmic microwave background 57 sunspot 57 cosmic ray 57 brown dwarfs 57 dwarf galaxies 57 neutrino 56 astronomers 56 Sedna 56 supernovas 56 nebula 56 planets orbiting 56 gamma ray 56 spiral galaxies 56 NASA Chandra 56 NASA Cassini spacecraft 55 Milky Way galaxy 55 Milky Way 54 supermassive black holes 54 galaxy 54 positrons 54 rocky planets 53 interstellar dust 53 Astronomers 53 solar flares 53 Betelgeuse 53 comets 53 Saturn rings 53 Gamma Ray 53 Gliese 53 Iapetus 52 Space Telescope 52 meteor shower 52 interstellar medium 52 Enceladus 52 asteroid 52 Spitzer Space Telescope 52 ringed planet 52 Cassini spacecraft 51 Big Bang 51 infrared wavelengths 51 starlight 51 aurora 51 corona 51 Mars Reconnaissance Orbiter 51 Perseids 51 laser pulse 51 nebulae 51 Cassini 51 cosmic rays 51 astrophysicists 51 WMAP 51 neutrinos 50 AGN 50 photons 50 auroras 50 spacetime 50 spectroscopic 50 unaided eye 49 Solar System 49 meteor 49 infrared radiation 49 Very Large Telescope 49 Cassiopeia 49 cometary 49 astrophysical 49 spectra 49 celestial objects 49 Astrophysical Journal Letters 49 photon 49 Saturn moon