Planetary scientists know that some of Jupiter's and Saturn's moons likely possess subsurface liquid-water oceans. These "ocean worlds," such as the Jovian moon Europa and the Saturnian moon ...

LITTLETON, Colorado — A university-led lunar orbiter designed to pinpoint the location of ice or liquid water trapped in rocks on the moon's surface is nearly ready for takeoff. The Lunar Trailblazer ...

And while Earth, of course, has plenty of active volcanoes of its own, eruptions on the Jovian moon have ... heat within the moon, keeping its subsurface crust in liquid magma form that seeks ...