Related by context. Frequent words. (Click for all words.) 60 vapor trail 59 contrails 54 plume 50 vapor cloud 47 plumes 46 meteor 46 gamma ray burst 45 ash plume 45 waterspout 45 fireball 44 sonic boom 44 planet orbiting 43 distant galaxy 43 Iapetus 43 X #B 42 NASA Cassini spacecraft 42 sky 42 clouds 42 corona 42 comet 42 meteor shower 42 quasar 42 funnel cloud 42 Saturn rings 42 supermassive black hole 42 nebula 42 supernova 42 aurora 41 crater 41 meteors 41 orb 41 Cassini spacecraft 40 gamma rays 40 auroras 40 sunspots 40 Perseids 40 sunspot 40 alien spacecraft 40 sonic booms 40 Thick smoke 40 galaxies 39 lava flows 39 Halley Comet 39 moon Titan 39 flyby 39 pulsar 39 troposphere 39 partial eclipse 39 planets orbiting 39 optical illusion 39 water vapor 39 neutron star 39 mushroom cloud 39 Saturn moon 39 orange glow 39 haze 39 exoplanets 39 bluish 38 lava flow 38 blobs 38 nebulae 38 vortices 38 ionosphere 38 orbits 38 brown dwarf 38 Betelgeuse 38 droplets 38 microburst 38 astronomers 38 molten rock 38 cloudiness 37 flying saucers 37 UFO sightings 37 extrasolar planets 37 crescent moon 37 galaxy clusters 37 gamma ray bursts 37 Lunar Crater Observation 37 billowing smoke 37 whitish 37 total lunar eclipse 37 UFO 37 Milky Way galaxy 37 blob 37 amateur astronomer 37 magnetosphere 37 gravitational waves 37 distant galaxies 37 supernovae 37 ash cloud 37 yellowish 37 funnel clouds 37 planets 37 astrophysicists 37 comets 36 fog 36 cloudy sky 36 craters 36 convective 36 flybys 36 grayish