Related by context. Frequent words. (Click for all words.) 58 galaxy NGC 57 polar vortex 57 auroral 56 X ray emission 56 visible wavelengths 55 aurorae 55 planetary nebula 54 moon Enceladus 54 ultraviolet wavelengths 53 Galileo spacecraft 53 planetary nebulae 53 Saturn moon Enceladus 53 Carina Nebula 51 CoRoT 51 NASA Cassini spacecraft 51 solar corona 51 photometry 51 galaxy cluster 51 substorm 51 noctilucent clouds 51 supernova remnant 50 planet Uranus 50 WASP #b 50 exosphere 50 tropospheric 50 GRB # 50 XMM Newton 50 supercell 50 VIRTIS 50 Cepheids 50 morphologies 49 Earthlike 49 ejecta 49 protostars 49 moonlets 49 Valles Marineris 49 SIRTF 49 magnetar 49 HAT P 49 Saturn rings 49 coronal hole 49 HiRISE camera 49 COROT 49 Gamma rays 49 infrared wavelengths 48 shorter wavelengths 48 gamma ray burst 48 Orion Nebula 48 Crab Nebula 48 excitations 48 solar nebula 48 Andromeda galaxy 48 comet tail 48 novae 48 Fig. 1A 48 interferometers 48 HD #b [002] 48 heavily cratered 48 optical wavelengths 48 cirrus 48 extrasolar planet 48 ionized gas 48 photometer 48 Mimas 48 ionised 48 supernova explosion 48 supercells 48 Opportunity rover 48 Olympus Mons 48 supergiant 48 unaided eye 47 GRBs 47 stellar nurseries 47 hydrothermal vent 47 sunspot 47 microlensing 47 GeV 47 dwarf galaxy 47 volcanic vents 47 interferometry 47 quasar 47 spatial scales 47 protoplanetary disk 47 planet orbits 47 oscillations 47 Photons 47 ionospheric 47 Eta Carinae 47 supernova remnants 47 aerosol particles 47 magnetars 47 Gliese #g 47 Saturn moon 47 planetesimals 46 supernova explosions 46 martian atmosphere 46 active galactic nuclei 46 super Earths 46 cirrus clouds 46 reddish hue 46 constellation Perseus