Jupiter Moons - Callisto discovered by Galileo Galilei in 1610 using a telescope. It is thought to have oceans of liquid water beneath its crust. about the size of Mercury, is the 3rd largest moon in the solar system. It is more heavily cratered than any other moon in the solar system. Callisto remains as it was when it formed, during the period of intense meteoroid bombardment that the entire solar system experienced
Enceladus, one of Saturn's moons. The Cassini spacecraft captured an image of plumes originating from the south pole of the icy moon with a very clear signature of small ice particles. There is possible evidence of Yellowstone-like geysers fed by reservoirs of liquid water.