Related by context. Frequent words. (Click for all words.) 61 sunspots 58 auroral 57 Sunspot 56 solar flares 56 substorms 55 aurora 54 X ray emission 54 auroras 54 sunspot activity 54 sunspot 53 Lunar Eclipse 52 geomagnetic storms 52 Meteorites 51 Orion Nebula 51 Perseids 51 magnetic fields 50 mid latitudes 50 CMEs 49 magnetosphere 49 volcanism 49 Neutrinos 49 cosmic ray 49 coronal mass ejections 49 polar caps 49 Geminids 49 meteor showers 48 geomagnetic 48 vortices 48 nebulae 48 Saturn moon Enceladus 48 Saturn rings 48 convective 48 Perseid meteor shower 48 dust devils 48 cirrus clouds 48 volcanic activity 48 Eruptions 47 cosmic rays 47 landforms 47 constellation Perseus 47 Leonids 47 Solar System 47 Volcanic eruptions 47 Earth magnetosphere 47 oscillations 47 moons 47 meteors 47 supermoon 47 equatorial regions 47 meteor shower 47 cumulus clouds 47 Black Holes 47 supernova explosions 47 ionized gas 47 Enceladus 47 aurora borealis 46 XMM Newton 46 gamma ray bursts 46 equinoxes 46 gamma ray burst 46 albedo 46 brown dwarfs 46 Kuiper belt 46 gamma rays 46 HD #b [002] 46 ENSO 46 meteoroids 46 infrared wavelengths 46 Andromeda Galaxy 46 lunar eclipses 46 starbursts 46 Aurora Borealis 46 constellation Leo 46 corona 46 ionosphere 46 El Ninos 46 extrasolar planets 45 GRBs 45 Iapetus 45 volcanoes 45 irradiance 45 Antimatter 45 latitudes 45 vortexes 45 unaided eye 45 galaxy clusters 45 Galaxies 45 gravitational waves 45 equatorial 45 supernovas 44 supernovae 44 Eta Carinae 44 volcanic eruptions 44 storminess 44 Astronomers 44 Uranus 44 comets 44 geomagnetic field 44 geologically active 44 geomagnetic storm 44 optical telescopes