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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Guest_Richard Trigaux_* |
Nov 23 2005, 07:22 AM
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Guests |
Thank you BruceMoomaw to quote papers which more or less confirm what my intuition told me.
When I was speaking of tidal heating, it was about the rocky core, when the papers you quote speak of tidal heating in the ice/water layer itself. Interesting to know that the water layer could sustain itself without the need of any volcanic activity into the rocky core. However, as far as I heard, scientists are inclined to think that Europa has some volcanic activity like Io. As much? or much less? Difficult to guess now. We can expect that there is at least some hydrothermal circulation, bringing tidal heat out of the core, and rising up into the water layer. Such a situation is interesting, as it would result into "black smokers" hydrothermal vents which could be oasis of life, with abundance of energy to feed chains of ecosystems. But this situation could also result in a sulphuric acid saturated ocean, which would avoid any form of life to exist or even to appear. If there are hydrothermal or volcanic activity in Europa ocean, we can expect it is turbulent, with plume of hot water rising up swiftly, and then falling again to the bottom when it gets colder than the 4°C barrier. If there is no such activity on Europa, we can on the countrary expect that the ocean is very still, very cold, with an unusual convection pattern due to the inverted law under 4°C. But indeed the cold source is at the top, so that a normal convection should occur at least at times. Enventually, with an inverted convection pattern, this very still ocean can be very pure of any dust, and thus reach a surfusion state. In this case, catastrophic mass freezing may occur, explaining the strange upheavals observed in many place on the surface. |
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