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ICLazeru t1_j2cpfly wrote

In the case of a moon orbiting a much more massive body, it's also possible that the gravitational tide of the larger body keeps the core molten. This would only work for so long as Pandora had rotational momentum of course, and over time the body would become tidally locked with the same side always facing its larger partner.

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The_Solar_Oracle t1_j2cqtx9 wrote

Pandora is probably tidally locked, but the kind of tidal forces responsible for prolonged geological activity for moons like Io also require special resonance orbits with other satellites. Europa and Ganymede have a 2:1 and 4:1 orbital resonance with Io respectively, and these resonances maintain Io's orbital eccentricity. Without this elegant dance of moons, the same tidal forces that physically distort Io would also circularize its orbit.

Interestingly, though, Pandora is also reliably depicted as being fairly close to Polyphemus (a planet that is itself slightly less massive than Jupiter). While there doesn't appear to be a canon figure available on the internet in regards to its orbital period (and, thus, lengths of its days), there is no doubt in my mind that James Cameron has figures to this end for use by the production team.

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