Saturn's Moon Enceladus Has Global Subsurface Ocean 72
An anonymous reader writes: NASA's Cassini probe has made another fascinating discovery: Enceladus, one of Saturn's moons, has an underground ocean spanning its entire globe. Researchers were trying to explain why the moon wobbles as it orbits Saturn, and they eventually came to the conclusion that its outer shell must be completely detached from its core. "The mechanisms that might have prevented Enceladus' ocean from freezing remain a mystery. Thomas and his colleagues suggest a few ideas for future study that might help resolve the question, including the surprising possibility that tidal forces due to Saturn's gravity could be generating much more heat within Enceladus than previously thought."
Slashdot ads (Score:3, Insightful)
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Well at least it's the sort of ad we might be inter... oh wait? It's for the "Must Consult Someone Experienced" cert?
Really, Slashdot, what would any of us do with that piece of crap? That sort of trash cert is more likely a reason to reject a resume than hire someone.
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True. But at least my company checks just what kind of certs you have before promoting. Having a "Minesweeper Consultant / Solitaire Expert" Cert usually means that you might be qualified for a janit... facility management position.
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Shhh... don't say that name. It's worse than with Hastur and Beetlejuice combined.
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You are clicking the check-box wrong. -Steve J.
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Oh, that's not an ad, it's a special offer.
Look, it's Dice, what did you expect? Giving a crap about the users?
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"Republican corporate welfare. Children are starving to death, but they instead want to funnel money by the truckload to corporations under the excuse of 'science'"
Meanwhile, the other guys defund science because of their hippie-chick fear of everything 'radioactive' or 'biological', or because the Hawaiian volcano god might be offended. Whatever your politics, if you want those children to be fed, you need to defend science.
Perpetual energy machine (Score:3)
I'm sure I'm wrong considering the laws of thermodynamics and all, but if a moon is heated by gravitational shifting, does this go on for ever? I.e. is this a perpetuum mobile?
Re:Perpetual energy machine (Score:5, Insightful)
It's NOT obvious because it's very gradual and there are multiple potential places the energy can be transferred from, such as Saturn's spin rate, the moon's orbital momentum, the moon's (past) rotation, the rings, and/or nearby moons. Resonance based energy transfer can be quite unintuitive.
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No, the orbit eventually decays.
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Every large moon in the Solar System is tidally locked, Enceladus included.
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Look into how heating on Io works. Io is tidally locked, but in a slightly non-circular orbit which provides plenty of tidal heating (the orientation isn't perfectly locked when the speed varies over the orbit and forces change as the moon moves slightly further and closer to the planet). Io's orbit stays eccentric because of interactions with other moons, so they behave as a system slowly losing energy. Enceladus has a smaller, more eccentric orbit than Io.
Re:Perpetual energy machine (Score:5, Informative)
No. Energy is being taken out every time. At some point it will become tidally locked, just like the Moon (of earth) and then the heating will stop.
Frozen Fish (Score:1)
No. Energy is being taken out every time. At some point it will become tidally locked, just like the Moon (of earth) and then the heating will stop.
Then all the fish freeze.
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Unless the Monolith implodes the planet into an artificial star.
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Tidal heating still goes on from non-circular orbits, uneven mass distribution (e.g. the wobbling), and slightly from other moons if they get close enough.
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I betcha that the rocky core of Enceladus is radioactive, as the Earth is, and that this is the heat source we are looking for.
Unknown energy (Score:3, Interesting)
I'm just throwing spit at a wall here cause it's fun. And fascinating.
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I guess you're not very far along in your physics studies, because you seem to lack a basic grasp of how sciene works. If for some reason you wish to posit the theory that Enceladus' ocean is kept unfrozen by the cumulative effect of energy from neutrinos and cosmic rays and such (and traditionally one would first eliminate more likely theories before going for the fringe stuff), by all means do so. Do some back-of-the-napkin calculations to figure out how much energy would be required from all those trace
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It is not an unknown mechanism. Io is tidally locked but is heated from tidal forces due to orbit eccentricity (that is maintained due to other moons). Enceladus has half the orbital distance of Io and is in a more eccentric orbit, so it shouldn't be a surprise that it is tidally heated. The big thing is knowing what is made of to have some idea what that heating does.
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Haha, that's exactly my attitude too :) It's almost a running joke that you launch a probe to anything in space and find out that it has an unexpectedly large amount of energy input ;) And I agree with your assessment that there's probably no single factor, just a lot of different energy sources that people haven't thought of. Unfortunately, humans tend to go into each situation with the blinders of experience, expecting things to be like that which we've already seen. The reality can be incredibly differ
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That said, I don't think that, say, gamma rays, neutrinos, etc would ever be a relevant energy source. But things that people don't immediately think of certainly could be. For example, in the above Pluto case: if you have a heavier nitrogen ice layer over a lighter water ice layer, and a chunk of the ice breaks through and floats to the surface... that's an energy input. That's moving the system to a lower energy state. In Enceladus, one energy source that's now believed to be going on is serpentinization
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I highly doubt neutrinos would actually be a heating source as well, I was just naming off mechanisms off the top of my head, not being series. As for gamma's, not in any large manner either, I was instead imagining VERY small pockets of heating, melting a s
Pluto Pump [Re:Unknown energy ] (Score:1)
The speculation on Pluto's dynamic surface is that as it cycles closer and further from the sun, the substances on its surface change densities relative to each other, creating a kind of pumping action.
For example, at the furthest point from the sun, substance A may be denser than substance B. But it could reverse near the closest point to the sun if A expands more than B under the increased heat (at that temperature). Thus A is pushed beneath B for part of the orbit, and then B is pushed beneath A for the
I wonder if there are dead fish at the south pole? (Score:3, Interesting)
Subsurface Ocean (Score:2)
Mmmmh, aren't _all_ oceans subsurface if you really consider it?
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mars lost more than it's atmosphere, it lost it's central core heating too.
no terraforma of mars until you can figure out how to jump start it's core with nukes.
Even more bizzare sub surface ocean! (Score:5, Interesting)
This ocean of molten iron exists just 1% of the planetary radius below the surface. Most people don't realize how close they are to this bizarre weird incredible iron ocean.
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This ocean of molten iron exists just 1% of the planetary radius below the surface.
Umm, more like 45% of the radius down. The mantle is a slowly forming, more plastic like rock, while the liquid iron outer core is much further down.
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All these worlds... (Score:3)
Attempt no landings there.
What are the chances... (Score:2)