Titan is Saturn's biggest moon and second-largest natural satellite. Titan has a thick atmosphere and rock-hard water ice. It presumably possesses a subsurface ocean of liquid water.
Ganymede is Jupiter's biggest moon. Ganymede is bigger than Mercury, Pluto, and Mars. Ganymede presumably harbors a saltwater ocean underneath its frozen surface, making it habitable.
Pan, Saturn's innermost moon, resembles ravioli. This tiny moon was found in 1990 and named after a Greek satyr.
NASA's Hubble Space Telescope observed water vapor on Europa, the solar system's sixth-largest moon and Jupiter's fourth-largest satellite. Under Europa's frozen surface may be a water ocean.
Scientists believe Phobos, the inner and bigger of Mars' two moons, is in a "death spiral" The natural satellite is named after the Greek deity Phobos, the origin of phobia.
Enceladus is Saturn's sixth-largest moon. It's an active moon that conceals a worldwideocean of liquid salty water under its crust.