Related by context. Frequent words. (Click for all words.) 65 distant galaxies 65 galaxy cluster 64 infrared wavelengths 64 XMM Newton 64 magnetosphere 63 galaxy clusters 63 interstellar medium 63 infrared radiation 63 ionosphere 63 cosmic rays 62 corona 62 interstellar dust 62 quasar 62 cosmic microwave background 62 gamma ray burst 61 gravitational waves 61 distant galaxy 61 supernova explosion 61 extrasolar planets 61 quasars 61 heliosphere 61 gamma rays 61 extrasolar planet 61 Saturn rings 60 galaxies 60 redshift 60 neutron star 60 NASA Cassini spacecraft 60 astrophysical 60 nebula 60 comet 60 spectroscopic 60 cosmic ray 60 Enceladus 59 HD #b [002] 59 cometary 59 supernovae 59 magnetic fields 59 brown dwarfs 58 comets 58 supernova 58 Solar System 58 gamma ray bursts 58 solar flares 58 ringed planet 58 unaided eye 58 neutrino 58 nebulae 58 THEMIS 58 terrestrial planets 58 exoplanets 58 astronomers 58 planets 58 supermassive black hole 57 CMEs 57 Martian atmosphere 57 exoplanet 57 celestial objects 57 sunspot 57 rocky planets 57 spectra 57 lunar surface 56 Iapetus 56 polar regions 56 brown dwarf 56 neutrinos 56 auroras 56 planet orbiting 56 aurora 56 Spitzer Space Telescope 56 spacetime 56 wavelengths 56 spatial resolution 56 supernovas 55 dwarf galaxies 55 Planck 55 troposphere 55 Milky Way galaxy 55 gamma ray 55 pulsars 55 Milky Way Galaxy 55 laser pulse 55 galaxy 55 outer planets 55 planets orbiting 55 laser pulses 55 MESSENGER 55 elliptical galaxies 54 orbits 54 dynamical 54 interstellar space 54 organic molecules 54 HiRISE 54 spiral galaxy 54 photons 54 Cassini 54 spectroscopy 54 GLAST 54 Betelgeuse 54 convective 54 pulsar