Europa is the solar system's smoothest object, suggesting its surface is remade by interior processes more frequently than most other worlds besides Earth. Ganymede The largest moon in our solar system might contain several layers of rock, water and exotic high-pressure ices. IN 2005 THE CASSINI SPACECRAFT VISITING SATURN FLEW THROUGH something engineers didn't expect - a fine water mist, spraying into space at 1,290 kilometers per hour through cracks in the surface of Saturn's tiny, ice-covered moon Enceladus. [Extracted from the article]