Which planet has a moon with active volcanoes?
1 Answer
Jupiter has a moon with lots of active volcanoes. That moon is Io.
Explanation:
The volcanoes on Earth are driven by tectonic motion, but on Io they are driven by the powerful tidal action of nearby Jupiter.
Aren't tides relatively gentle phenomena? On Earth the tides appear that way because we have only weak tidal sources to contend with. The Moon is relatively small and the Sun is relatively far away. Io has Jupiter which is both massive and close at the same time. The Jovian tides heave Io's body back and forth, generating tremendous frictional hearing that melts the rock and forces that constantly propel this magma to the surface.
The resulting volcanic activity far exceeds that on Earth and -- unlike most bodies in the outer Solar System -- it has driven off all the water. Io is incredibly dry, even compared with our own quiescent Moon.
On some other outer-planet moons, where tidal forces are not as strong, ice remains on the surface but can be melted internally and driven to the surface in "cryovolcanoes" ("cold volcanoes"). Saturn's moon Enceladus is an example of this modified form of volcanism.
