Interiors of Icy Bodies

Explanation: Many bodies in our solar system may contain oceans. Jupiter's ice-coated moons (Europa, Ganymede, and Callisto) probably contain internal saltwater oceans. The more distant large and medium-sized icy moons, the icy dwarf planets, and tiny Enceladus may contain colder ammonia-water oceans. Oceans in icy satellites could be a common feature throughout the universe, while Earth's surface ocean may be the more unusual case. These interior models were developed by many geophysicists from data about the sizes, densities, and orbital characteristics of each body.

Pluto

Image credit: Doug Ellison, Emily Lakdawalla, and Bob Pappalardo.