title: Planetary science. Did a battering rain of comets bring Ganymede to geologic life?
authors.forename: Richard A
authors.initials: RA
authors.lastname: Kerr
mesh_terms: D019419:Evolution, Planetary; D005118:Extraterrestrial Environment; D007053:Ice; D018538:Jupiter; D019110:Meteoroids
chemical_list: D007053:Ice