Related by context. Frequent words. (Click for all words.) 69 supernovae 68 supernovas 66 gamma ray bursts 65 globular clusters 64 gamma ray burst 64 quasars 64 supernova 63 pulsars 62 galaxy clusters 62 elliptical galaxies 62 galaxies 61 brown dwarfs 61 spiral galaxies 60 nebulae 60 neutron stars 59 dwarf galaxies 58 XMM Newton 58 neutron star 58 distant galaxies 58 supernova explosion 58 quasar 58 astrophysicists 58 astronomers 57 cosmologists 57 redshift 57 planets 57 distant galaxy 56 supermassive black holes 56 gamma rays 56 CMEs 56 galaxy cluster 56 comets 56 moons 56 gravitational waves 55 Saturn rings 55 extrasolar planets 55 nebula 55 Betelgeuse 55 nuclei 55 celestial objects 54 brown dwarf 54 cosmological 54 planets orbiting 54 general relativity 54 astrophysical 54 X ray Observatory 54 galaxy 53 luminosity 53 NASA Chandra 53 comet 53 gravitational lensing 53 rocky planets 53 pulsar 53 solar flares 53 exoplanets 53 cosmic rays 53 terrestrial planets 53 positrons 53 meteors 53 Milky Way 53 sunspot 53 auroras 52 corona 52 asteroids 52 planet orbiting 52 spacetime 52 Milky Way galaxy 52 Astronomers 52 WMAP 52 neutrino 52 cosmic microwave background 51 spiral galaxy 51 supermassive black hole 51 infrared wavelengths 51 Cassiopeia 51 gamma ray 51 fainter 51 wavelengths 51 HD #b [002] 51 magnetic fields 50 Milky Way Galaxy 50 interstellar medium 50 neutrinos 50 spectroscopic 50 aurora 50 cosmic ray 50 laser pulses 49 exoplanet 49 extrasolar planet 49 sunspots 49 Einstein theory 49 Earths 49 photons 49 subatomic particles 49 meteor showers 49 atomic particles 49 constellations 49 orbits 48 Perseids 48 spectra 48 meteor