Related by context. Frequent words. (Click for all words.) 63 X ray emission 61 XMM Newton 61 Orion Nebula 60 astronomical objects 59 luminosity 59 nebulae 59 unaided eye 58 infrared wavelengths 58 supernova remnant 58 starbursts 58 HD #b [002] 58 Saturn rings 57 GRBs 57 planet orbiting 57 Mimas 57 planets orbiting 57 nebula 57 Andromeda Galaxy 57 Eta Carinae 57 supernova explosion 57 spiral galaxy 56 Andromeda galaxy 56 cosmic microwave background 56 quasars 56 extrasolar planets 56 distant galaxy 56 iridescence 56 interstellar dust 55 gamma ray burst 55 Milky Way 55 auroral 55 luminous 55 ecliptic 55 astronomers 55 Milky Way Galaxy 55 elliptical galaxies 54 magnetar 54 spiral galaxies 54 distant galaxies 54 brightness 54 celestial object 54 extrasolar planet 54 ejecta 54 planets 54 Spitzer Space Telescope 54 rocky planets 54 Saturn moons 54 galaxy cluster 54 spectroscopic 54 Betelgeuse 54 celestial bodies 53 supernova 53 infrared 53 Milky Way galaxy 53 quasar 53 brown dwarfs 53 Jupiter moons 53 Iapetus 53 moons 53 constellations 53 constellation Leo 53 habitable planets 53 accretion disk 53 globular clusters 53 ringed planet 53 corona 53 cosmos 52 brown dwarf 52 moon Charon 52 NASA Cassini spacecraft 52 starlight 52 gravitational lensing 52 bluish 52 COROT 52 ellipse 52 aurora 52 Perseids 52 celestial objects 52 comet 52 striations 52 exoplanets 52 Geminids 52 galaxy formation 51 optical telescopes 51 muon 51 supernovas 51 galaxies 51 ultraviolet light 51 globular cluster 51 photometric 51 Saturn moon Enceladus 51 starburst 51 reddish color 51 auroras 51 Enceladus 51 speckles 51 Pleiades 51 terrestrial planets 51 Large Magellanic Cloud 51 WMAP 51 constellation Perseus