Moons Worth Exploring

Jupiter's moon Europa hides a global ocean of liquid water beneath its icy crust, kept warm by tidal heating from Jupiter's gravity. That ocean may contain more water than all of Earth's oceans combined. It is one of the most promising places in the solar system to search for extraterrestrial life.

A Tale of Two Moons

Saturn's moon Titan is wrapped in a thick atmosphere — denser than Earth's — and has lakes and rivers of liquid methane and ethane on its surface. Enceladus, another Saturn moon, is far smaller but just as intriguing: it shoots geysers of water ice from its south pole.