Related by context. Frequent words. (Click for all words.) 67 Gamma ray bursts 66 magnetars 65 planetary nebulae 63 active galactic nuclei 62 planetary nebula 62 X ray emission 61 Cepheids 61 GRBs 60 supernova explosions 60 Crab Nebula 59 globular clusters 59 dwarf galaxies 59 haloes 59 supernova remnants 59 Gamma rays 59 Kuiper Belt objects 59 elliptical galaxies 59 supernovae 59 Pulsars 58 globular cluster 58 Betelgeuse 58 Eta Carinae 58 dwarf galaxy 58 supernova explosion 58 brown dwarfs 57 WASP #b 57 star Gliese 57 Type Ia supernovae 57 magnetar 57 supernova 57 supernovas 57 nebulae 57 photometer 57 fluorescing 57 super Earths 56 olivine 56 pulsars 56 brown dwarf 56 moonlets 56 planet orbiting 56 supernova remnant 56 hot Jupiters 56 baryons 56 Cancri 56 XMM Newton 56 Cosmic rays 56 radial velocity 55 spiral galaxies 55 auroral 55 galaxy clusters 55 quasar 55 quasars 55 habitable planets 55 GRB # 55 colliding galaxies 55 WIMPs 55 Hawking radiation 55 morphologies 55 aurorae 55 astronomical objects 55 Orion Nebula 54 redshifts 54 Andromeda Galaxy 54 particle detectors 54 terrestrial planets 54 HD #b [002] 54 supermassive black holes 54 rocky planets 54 galaxy cluster 54 Galaxy Evolution 54 ionized gas 54 neutron stars 54 microlensing 54 gamma ray burst 54 Astrophysicists 54 interferometers 54 extrasolar planet 53 accretion disk 53 planets orbiting 53 distant galaxies 53 subatomic particle 53 planetesimals 53 silicates 53 exoplanets 53 optical wavelengths 53 excitations 53 Higgs particle 53 planet orbits 53 solar flares 53 solar corona 53 nebula 53 colliders 53 optical telescopes 53 starbursts 53 ejecta 52 Andromeda galaxy 52 Fig. 1A 52 fluorophores 52 unaided eye 52 gravitational lensing 52 planets circling