Flexi Says: Scientists think that some of Jupiter's largest moons could possibly harbor life forms. Europa, Ganymede, and Callisto all show evidence of oceans under their icy surfaces, and each has a thin atmosphere. However, any life forms on these moons would have evolved adaptations to some rather extreme conditions. The surface temperatures of the moons are far colder than even the coldest places on Earth. Jupiter emits a large amount of radiation that bombards its inner moons. Any life would most likely be in the underground oceans. Humans are not adapted to live in these types of environments.