Astronomy 426 Stars 257 History 172 Cosmology 169 Astrophysics 129 Planets 82 Galaxies 72 more ... Astronomers 56 Rotation 56 Mass 53 Radiation 52 Age 49 Density 48 Seasons 48 Transits 48 Aeronautics 47 Core 47 Mantles 47 Wind erosion 47 Winds 47 Life on other planets 46 Variable stars 43 Origin 42 Spectra 42 Evolution 41 Exploration 38 Comets 35 Catalogs 33 Observations 32 Nebulae 29 less ...