Related by context. Frequent words. (Click for all words.) 64 planetary nebula 63 planetary nebulae 63 Crab Nebula 60 Andromeda galaxy 59 Orion Nebula 59 nebulae 59 Andromeda Galaxy 58 supernova remnant 58 nebula 58 distant galaxy 57 unaided eye 57 solar corona 57 Galaxy Evolution 57 spiral galaxy 57 XMM Newton 57 supernova remnants 56 Milky Way Galaxy 56 spiral galaxies 56 aurorae 56 Saturn rings 56 Jupiter Saturn 56 galaxy cluster 56 colliding galaxies 56 auroral 56 astronomical objects 56 magnetars 56 distant galaxies 56 cigar shaped 56 supernova explosion 56 Betelgeuse 55 NASA ESA Hubble 55 GRBs 55 gamma ray burst 55 Mimas 55 starbursts 55 celestial object 55 galaxy 55 constellation Orion 54 ringed planet 54 Kuiper belt 54 Fomalhaut 54 X ray emission 54 Gamma ray bursts 54 COROT 54 active galactic nuclei 54 Cancri 54 interferometry 54 Eta Carinae 54 comet nucleus 53 Voyager spacecraft 53 corona 53 constellation Leo 53 Astrophysicists 53 accretion disk 53 globular cluster 53 coronal 53 Comet McNaught 53 Halley comet 53 NASA Cassini 53 GRB # 53 globular clusters 53 radial velocity 53 galaxy formation 53 Iapetus 52 quasar 52 photometry 52 comet 52 meteoroid 52 magnetar 52 Oort Cloud 52 Hubble observations 52 hot Jupiters 52 star Gliese 52 Jupiter moons 52 Milky Way galaxy 52 ecliptic 52 gamma ray bursts 52 comet tail 52 planets 52 magnetic reconnection 52 dwarf galaxy 52 planet orbiting 52 occultation 52 orbiting planets 52 Sedna 52 galaxies 52 aurora 52 Type Ia supernovae 52 NASA Chandra 52 Cosmic rays 52 morphologies 52 galaxy clusters 51 planets orbiting 51 Spitzer Space Telescope 51 Large Magellanic Cloud 51 NASA Cassini spacecraft 51 meteoroids 51 Hubble Telescope 51 HD #b [002] 51 Aurora Borealis 51 supernovas