Europa Subsurface Ocean |
Europa Subsurface Ocean |
Nov 22 2005, 10:53 AM
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
Regarding the very real possibility Europa harbors an ocean underneath the ice, I'm wondering whether there have been any estimates on how long such an ocean might have been sustained (I'm assuming it's still there today). Are we talking about the entire history of Europa, billions of years or a much more recent thing, only a few millions? I know Enceladus, which recently turned out to be much warmer inside than expected, could have been periodically heated, but not on very long timescales.
I'm primarily interested because of the habitability factor, obviously an ocean which freezes out every once and a while would not make for a good incubator to possible life. Also, supposedly all tidal heating on Europa would cease now, how long would it take for the subsurface to freeze out, that is, what are the thermal conductive properties of the surface ice? Admittedly, I haven't done much research on the subject and if the question was already asked before, I apologize. -------------------- |
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Nov 22 2005, 03:36 PM
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#2
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Member Group: Members Posts: 509 Joined: 2-July 05 From: Calgary, Alberta Member No.: 426 |
The history of Europa has to be very closely tied to its orbital resonances with Io and Ganymede. These resonances are what keep Europa's orbit around Jupiter slightly elliptical. Without the resonances, tidal dissipation would cause Europa's orbit to become circular (as it did with Triton) and heating would cease.
So the question is really: Have Io, Europa and Ganymede always been in these resonances (perhaps also with Callisto at one time)? If they have, you can bet that Europa's subsurface ocean has always been at least as warm as it is now. I say "at least" because, like all "regular" satellites, the Galileans are slowly moving away from their parent planet, which means that tidal effects would've been stronger in the past when Europa was a bit closer to Jupiter. |
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