Problem
Despite being smaller than any of the planets, Jupiter's moon Io experiences intense volcanism, and another of its moons, Europa, has a very young surface and (most likely) a liquid water ocean under its icy shell.
1. What process provides the heat and energy that drives the geological activity on these satellites?
2. What would happen to their level of geological activity if they were taken away from Jupiter and placed on their own orbits around the sun? Explain your reasoning.