Related by context. Frequent words. (Click for all words.) 62 auroras 62 X ray emission 61 Geminids 61 ejecta 61 Orion Nebula 60 Saturn rings 59 comets 59 GRBs 59 aurora 59 distant galaxies 59 supernova explosion 59 XMM Newton 59 extrasolar planet 59 extrasolar planets 58 nebulae 58 terrestrial planets 58 rocky planets 58 astrophysical 58 globular clusters 57 elliptical galaxies 57 cosmic rays 57 HD #b [002] 57 celestial objects 57 supernovas 57 geomagnetic 57 brown dwarfs 57 supernova explosions 57 cosmic microwave background 57 Leonids 57 gravitational lensing 56 meteor showers 56 supernovae 56 Saturn moons 56 occultation 56 gamma ray bursts 56 ringed planet 56 Enceladus 55 sunspots 55 comet 55 spiral galaxies 55 gamma ray burst 55 exoplanets 55 CloudSat 55 Jupiter moons 55 Eta Carinae 55 interstellar dust 55 supernova remnant 55 quasars 55 ionosphere 55 Milky Way Galaxy 55 NASA Cassini spacecraft 54 Spitzer Space Telescope 54 sunspot 54 comet nucleus 54 Iapetus 54 infrared wavelengths 54 THEMIS 54 brown dwarf 54 equatorial regions 54 cosmic ray 54 outer planets 54 planets 54 mid latitudes 54 quark gluon plasma 54 Martian surface 54 orbiting spacecraft 54 Betelgeuse 54 albedo 54 unaided eye 54 astronomers 54 ESO Very Large Telescope 54 meteors 54 northern latitudes 53 planets orbiting 53 cometary 53 polar regions 53 spectroscopic 53 distant galaxy 53 super Earths 53 aurora borealis 53 HiRISE 53 galaxies 53 Halley Comet 53 Perseids 53 gravitational waves 53 Astrophysical Journal 53 Astrophysical Journal Letters 53 olivine 53 silicates 53 optical telescopes 53 planet orbiting 53 troposphere 53 neutrinos 53 pulsars 53 dust devils 52 galaxy cluster 52 moon Titan 52 dwarf galaxies 52 astronomical observations 52 exoplanet 52 Saturn moon