Related by context. Frequent words. (Click for all words.) 66 ecliptic 56 poleward 56 infrared wavelength 56 solstices 55 perihelion 55 photosphere 55 constellation Gemini 54 counterclockwise direction 54 planet Uranus 54 latitudinal 54 tropospheric 54 mesosphere 54 Cepheids 54 innermost planet 53 tropopause 53 heliosheath 53 gaseous planets 53 constellation Leo 53 substorm 53 equinoxes 53 Jupiter Saturn 53 coronal hole 53 optical wavelengths 52 longitudes 52 equator 52 occultation 52 Kuiper belt 52 constellation Orion 52 Oort Cloud 52 Olympus Mons 52 constellation Sagittarius 51 aurorae 51 exosphere 51 metallicity 51 galaxy NGC 51 auroral 51 southwestward 51 orbiting planets 51 anisotropy 51 gravitational lens 51 ellipse 50 Eurasian continent 50 circular orbits 50 southeasterly direction 50 faintly visible 50 solar corona 50 polar vortex 50 anticlockwise 50 Carina Nebula 50 circular orbit 50 constellation Perseus 50 diffraction pattern 50 equatorial 50 highly elliptical orbit 50 heliosphere 49 cm -1 49 eastern equatorial Pacific 49 erosional 49 Fomalhaut 49 coronal 49 heavily cratered 49 Martian dust 49 Earth magnetosphere 49 southeasterly 49 geomagnetic 49 Mauna Kea Hawaii 49 lithosphere 49 magnetic reconnection 48 outermost 48 Lagrangian 48 obliquity 48 anticyclone 48 northeasterly direction 48 counter clockwise direction 48 ITCZ 48 Tharsis 48 Eagle Nebula 48 ultraviolet wavelengths 48 mid latitudes 48 Apennines 48 perpendicularly 48 Valles Marineris 47 southwesterly direction 47 ellipsoid 47 z = 47 electron spins 47 Andromeda galaxy 47 electron density 47 X ray emission 47 celestial object 47 comet tail 47 equatorial Pacific Ocean 47 umbra 47 redshifts 47 polarizations 47 Cosmic rays 47 upper troposphere 47 polar caps 47 Fig. 1A 47 Comet McNaught 47 interplanetary spacecraft