When will Io's volcanoes stop?

[Tom Mazanec]

I don't believe in perpetual motion, so when will Io's volcanoes run out?

[phunk]

I don't know if we have enough info to answer that. I'd assume Io would start to settle down once it's tidally locked with jupiter, since the volcanoes are thought to be powered by tidal forces.

[Arneb]

Io is already tidally locked with Juptiter. The tidal forces and thus the volcanism stems from the fact that the orbit is not circular.

I suppose this should keep the volcanism going for longer than the Solar system is likely to last.

[Tom Mazanec]

Jupiter's orbit will expand as the sun loses mass. "Roasters" prove that Jupiter should survive the sun's red giant phases, and so should Io, since it is not composed of ice. They should last a LONG time.

[Arneb]

Then probably Io's volcanism is going to outlast Earth's - or even Earth herself

[tony873004]

If Io were the only moon around Jupiter, the tide Io pulls on Jupiter would tend to circularize Io's orbit. Then the volcanoes would not have a source of energy and they would stop.

But Europa and Ganymede are in resonance with Io and this resonance restores any eccentricity lost by the circularization process. As a result, Io, Europa and Ganymede migrate out from Jupiter. One day Ganymede's 2:1 exterior resonance will cross the orbit of Callisto, and Callisto will join the 3 inner Galilean moons in their resonance. As the Galilean moons spiral out, the tidal force will weaken and at some point, it will cross a certain threshold and Io will no longer receive enough energy for its volcanoes.

[Arneb]

Fascinating. To come back to TMs OP - Will that be before the end of the Solar ssystem as we know it, or is this happening over really large time spans?

[George]

Io, IIRC, is withing Jupiter's strong magnetic field which causes trillions of watts of energy to be generated. This might contribute as well, but I am not sure.

[Peter Wilson]

If Io were the only moon around Jupiter, the tide Io pulls on Jupiter would tend to circularize Io's orbit. Then the volcanoes would not have a source of energy and they would stop.

But Europa and Ganymede are in resonance with Io and this resonance restores any eccentricity lost by the circularization process. As a result, Io, Europa and Ganymede migrate out from Jupiter. One day Ganymede's 2:1 exterior resonance will cross the orbit of Callisto, and Callisto will join the 3 inner Galilean moons in their resonance. As the Galilean moons spiral out, the tidal force will weaken and at some point, it will cross a certain threshold and Io will no longer receive enough energy for its volcanoes.

The resonance part is correct, but if gravitational energy is powering the volcanos, then the satellites will be spiraling in, not out. Io is "falling," and dragging the others with it.

[pghnative]

The resonance part is correct, but if gravitational energy is powering the volcanos, then the satellites will be spiraling in, not out.

Why would that be true? The earth is transfering energy to the moon by tidal forces, and the moon is spiralling out. Why would Io be any different?