Europa is the sixth largest satellite in our Solar System and the smallest of Jupiter’s four Galilean moons. Discovered by ...

Astronomers have uncovered new evidence that Jupiter’s moon Callisto likely harbors a massive underground ocean, potentially ...

In the 1990s, however, NASA's Galileo spacecraft captured magnetic measurements near Callisto that suggested that its ice shell surface—much like that of Europa, another moon of Jupiter—may ...

NASA's Galileo mission, which launched into space ... If true, that would make Callisto a close sibling to Europa, another moon of Jupiter. Though the existence of an ocean remains inconclusive ...