Related by context. Frequent words. (Click for all words.) 65 solar flares 62 gamma ray burst 61 comet 60 neutron star 58 supermassive black hole 58 gamma rays 58 supernova 58 meteor 58 magnetosphere 58 quasar 57 sunspot 56 cosmic ray 56 auroras 55 impactor 55 asteroid 54 cosmic rays 54 nebula 54 #/#Z 54 supernovae 53 aurora 53 supernovas 53 pulsar 53 meteor shower 53 planet orbiting 53 volcanism 53 comets 52 Saturn rings 52 gamma ray bursts 52 distant galaxy 52 STEREO 52 asteroids 52 quasars 51 convective 51 corona 51 protons 51 interstellar space 51 galaxies 50 meteors 50 geomagnetic field 50 ionosphere 50 gravitational waves 50 spiral galaxy 50 Enceladus 50 galaxy clusters 49 sunspots 49 waterspout 49 neutron stars 49 astronomers 49 heliosphere 49 Iapetus 49 orbiting 49 Halley Comet 49 positrons 49 supermassive black holes 48 particles 48 lava flows 48 comet Tempel 1 48 Sensing Satellite 48 brown dwarf 48 magnetic fields 48 galaxy 48 molten rock 48 orbits 48 magma 48 Tempel 1 48 volcanic eruptions 48 fireball 47 Betelgeuse 47 Lunar Crater Observation 47 vortices 47 Uranus 47 plume 47 meteorite 47 planets 47 laser pulse 47 Cassiopeia 47 microburst 47 X ray Observatory 47 neutrinos 47 eruption 46 convection 46 exoplanets 46 subatomic particles 46 water vapor 46 rocky planets 46 neutrino 46 infrared radiation 46 lava 46 Perseids 46 brown dwarfs 46 nuclei 46 NASA Chandra 46 crater 46 dwarf galaxies 46 Sedna 45 NASA Cassini spacecraft 45 cosmic microwave background 45 planets orbiting 45 LCROSS 45 eyewall 45 spacecraft