Ceres Geology |
Ceres Geology |
Jan 22 2014, 06:14 PM
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#1
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Rover Driver Group: Members Posts: 1015 Joined: 4-March 04 Member No.: 47 |
Paper out tomorrow: http://www.bbc.co.uk/news/science-environment-25849871
Very exciting that we will visit this world soon! |
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Mar 13 2015, 03:30 PM
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#2
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Member Group: Members Posts: 495 Joined: 12-February 12 Member No.: 6336 |
Nice work there Gerald, really good even.
I really tried to find a mistake there, but you seem to have made a good estimate. A layer of liquid water might be possible, especially if there's small amounts of other radioactive elements adding to the energy budget as well. Before reading the paper mcgyver linked, I never did take the pressurisation into account, so I capitulate to the idea that Ceres indeed could have one subsurface ocean - but I still not saying it's there, even though I bet 'some' website featuring space related news quite likely will make a bold statement of 'discovery' any day after this. =) |
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Mar 13 2015, 03:59 PM
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#3
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
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Mar 14 2015, 01:56 PM
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#4
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Member Group: Members Posts: 495 Joined: 12-February 12 Member No.: 6336 |
Thanks a lot for the review! There is always a risk to make a mistake with this lot of numbers. So you thank me for trying to show you're wrong. Well serious, it's a good back-of-the-envelope kind of calculation to show the idea is worth considering. To actually get to the bottom of things (silly pun intended) one have to go quite further to include the pressure of the water down there, some numbers provided in the paper. That gives how the water might rise in the tube even in the very low gravity of Ceres. It is at that point these guys from the Planetary Science Institute, CIT and JPL adds the fact that there should be heavier material on top of the ice sheet covering Ceres that increase the pressure further. Then adding at least a partial melting of ice, at the highest part the tube. Here I am lazy and enter my own calculations made for the aquifers in a lime rock environment that keeps flowing trough the winter in sub arctic conditions. the flow of water here is a magnitude lower in general, and the strongest flow I got just barely is the same ballpark (4 litres/s) as the measurements made by Herschel. But I still don't get this to work, if water have frozen out and it ended up with one of a handful of pockets with water of very high salinity - perhaps. Or more heat is needed, meaning the presence of heat produced by the decay of some other long lived elements. Salts also would prevent freezing in the tube, and even melt some ice of lower salinity in the lower parts. And at that point I realise that some press releases have been mentioning salts and not ice as one explanation for the bright spots. They certainly have done the calculations better than me, even so it was one interesting exercise to get a glimpse of how the planetary scientists have been thinking. |
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