The Astronomy Thread
- Thread starter Araxen
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Guest, it's time once again for the massively important and exciting FoH Asshat Tournament!
Go here and give us your nominations!Who's been the biggest Asshat in the last year? Give us your worst ones!
opiate82
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I readily admit my ignorance but as I understand it they still believe the ocean is down there, but likely void of life.
Big Phoenix
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I guess because it means it doesnt interact at all with the surface thus no chance for surface material to get into the water to seed it with life?
Big Phoenix
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iannis
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It ain't easy to drill through a few miles of ice on earth. I think at the very least it puts the oceans out of reach.
The theory favoring life, as far as I remember it, was that life would most likely exist in the vents and crevasses rather than the giant ocean. Fewer to no vents makes that theory more difficult to unpossible. An ocean capped by a few miles of ice would be a closed system.
The theory favoring life, as far as I remember it, was that life would most likely exist in the vents and crevasses rather than the giant ocean. Fewer to no vents makes that theory more difficult to unpossible. An ocean capped by a few miles of ice would be a closed system.
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So if it does have hydrothermal vents spewing minerals and shit, would the ice just gather and disperse all that heat easily or would it 'find' a way out? A single shaft through the ice to the surface as a way of opening the system?
Where's tad?
Where's tad?
Tolan
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All else being solid ice, a hydrothermal vent could create a perpetual chamber of liquid water. The size of which would depend on the amount of heat energy coming from the vent, the ambient temperature of the ice surrounding it, and salts in the water. Vents aren't necessarily required to create a subsurface ocean, if the core of Europa outputs enough heat energy to melt some thickness of the ice.
Specifically hydrogen in particular is very good radiation shielding (against fast neutrons) which makes wateramazingshielding. This is also why neutrons do a lot more damage to living beings than alpha or beta particles - we're sacks of hydrocarbons mostly full of water so the same physics which makes water good at absorbing that radiation also makesusgood at absorbing it, to the detriment of biological structures.
opiate82
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I think that pretty much nails it, except now they think that the water blasting 200km into the sky was caused by a regular old meteor strike instead of super-awesome hydrothermal vents. Plus since they now figure Europa's atmosphere is apparently made up with a bunch of shit it picked up from Io thanks to newly analysed data from Cassini, that apparently has something to do with nerfing the possibility of life there as well.
Big Phoenix
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iannis
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It's a fair question that I don't know the answer to. I'll hazard a few guesses though. 1) It's the best shot because we've now looked at the other wild guess best shots and, while we've had some remarkable discoveries (not just water on mars, but small amounts of liquid water which perceptibly flows, just very slowly) we haven't had that one particular discovery. b) It's harder to land at a pole than it is to plunk down in the middle of a big fat crater. ?) These have been general geological missions, and the poles are of less varied interest for initial surveys.