Related by context. Frequent words. (Click for all words.) 65 gamma ray bursts 62 auroras 62 gamma ray burst 61 solar flares 60 cosmic ray 59 aurora 58 magnetosphere 57 oscillations 57 supernovae 56 gravitational waves 56 quasars 55 magnetic fields 55 THEMIS 55 meteor shower 55 neutrinos 55 neutron star 55 sunspots 55 aurora borealis 55 neutrino 55 galaxy clusters 55 comets 55 heliosphere 54 meteor showers 54 extrasolar planets 54 cosmic rays 54 rocky planets 53 distant galaxy 53 astronomers 53 brown dwarfs 53 supernova 53 pulsars 53 ionosphere 53 planets 53 astrophysical 53 geomagnetic field 53 neutron stars 53 distant galaxies 53 celestial objects 53 gamma rays 53 Saturn rings 53 volcanism 52 supermassive black hole 52 ringed planet 52 equinox 52 galaxies 52 laser pulses 52 brown dwarf 52 orbits 52 vortices 52 cosmologists 52 subatomic particles 52 comet 52 atomic particles 52 impactor 51 astrophysicists 51 Perseids 51 sunspot 51 quasar 51 photons 51 Solar System 51 XMM Newton 51 atmospheric circulation 51 exoplanets 51 Enceladus 50 dynamical 50 cosmic microwave background 50 NASA Cassini spacecraft 50 planet orbiting 50 protons 50 exoplanet 50 polar regions 50 laser pulse 50 Iapetus 50 supernovas 50 nuclei 50 convective 50 pulsar 50 chemical reactions 50 supermassive black holes 49 neutrons 49 infrared wavelengths 49 MESSENGER 49 WMAP 49 Astronomers 49 solar eclipses 49 Milky Way galaxy 49 atoms 49 electron spin 49 celestial bodies 49 asteroids 49 Cassini 49 oscillation 49 radioactive decay 49 greenhouse warming 48 seismic waves 48 orbiting 48 volcanic activity 48 spacecraft 48 flyby 48 X ray Observatory 48 redshift