Oceans inside Jupiter's moons

摘要

For almost 50 years, exploration of the large Galilean moons of Jupiter has delivered a continuing stream of surprises. The four moons — Io, Europa, Ganymede and Callisto — have increasingly come to appear as an exotic and remarkably diverse planetary system in their own right. In 1979 we had the discovery of the most dramatic volcanism known in the Solar System, on the innermost Galilean satellite Io, during the Voyager space mission; and in 1996 the Galileo spacecraft revealed that Ganymede has a strong magnetic field, probably stemming from an internal dynamo.