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Originally Posted by Northwind
Same process as Jupiter's interaction with Io?  |
Exactly the same process, yes.
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guess they forgot the
How many watts to "boil" water ?
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No, because there isn't a flux tube between Saturn and Enceladus.
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eccentricity??? Now I read somewhere bodies moving on eccentric orbits displayed some unusual properties.
surely they couldn't be saying they may have a common cause for both phenomena? Are they? Is it tidal flexing, radioactive core maybe mixed in with some "organic stuff" or indeed the same as Io?
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Yes, they are. The eccentric orbit is what causes the heating - it's all down to the fact that the satellite is repeatedly getting closer and further from its massive primary. It doesn't matter if the primary is Jupiter, Saturn, or anything else - so long as that eccentricity is maintained, the heating will continue. In extreme cases, it's enough to melt significant amounts of the rocky material inside the planet (as it does on Io) - in less extreme cases it just melts ice (like on Enceladus and the other Galileans satellites).
To answer dhd40's question, the key is that the eccentricity must be
maintained. Left on its own, the heating would cause the satellite's orbit to circularise, and when it's fully circular there'd be no more tidal heating. But in a system with other satellites (like Jupiter's or Saturn's), those satellites can give eachother regular gravitational tugs (particularly if they're in resonances) that keep the orbit eccentric.
It's like being on a swing in a playground. If just give one push, then the swing eventually stops swinging. But if you keep on pushing, the swing continues to swing as long as that's maintained. If you keep on pushing
regularly, then that's similar to what an orbital resonance is.
Other things like electrical heating from flux tubes, or radioactive heating from decay in the interior also contribute, but tidal heating can be and often is much greater than either of these contributions.