Martian Hydrology |
Martian Hydrology |
Nov 23 2010, 08:46 PM
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#1
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
An interesting article from Space Daily today: http://www.marsdaily.com/reports/Shallow_G...n_Mars_999.html
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Dec 7 2010, 08:06 PM
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#2
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Member Group: Members Posts: 555 Joined: 27-September 10 Member No.: 5458 |
And most people forget that the ground has pressure as well.
Edit: I guess I overlooked your last line. Yes, in this sense, it would be rare for liquid water to ever exist on the surface of Mars. However, honestly I have no idea what temperature water would need to be to exist as liquid. I will have to calculate that out. Edit 2: Heres and interesting link. I found this on a quick search. Looks like a good read for this thread. -------------------- |
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Dec 8 2010, 02:19 AM
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#3
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Junior Member Group: Members Posts: 59 Joined: 12-November 09 Member No.: 5039 |
And most people forget that the ground has pressure as well. Edit: I guess I overlooked your last line. Yes, in this sense, it would be rare for liquid water to ever exist on the surface of Mars. However, honestly I have no idea what temperature water would need to be to exist as liquid. I will have to calculate that out. Water needs 0 C or 273 K to become liquid. Even on Mars. Melting temp depends only weakly on pressure. QUOTE Edit 2: Heres and interesting link. I found this on a quick search. Looks like a good read for this thread. Here is an photo example of mini-gullies on Earth which definitely are not formed by water: http://uploaded.fresh.co.il/2007/03/16/46040681.jpg I know it is far from being scientific, but still... |
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Dec 8 2010, 03:47 AM
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#4
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Member Group: Members Posts: 555 Joined: 27-September 10 Member No.: 5458 |
Water needs 0 C or 273 K to become liquid. Even on Mars. Melting temp depends only weakly on pressure. That isn't really all that true. Pressure can play a large part in the melting point, especially when you consider other factors such as water purity. Seawater for instance, freezes at -2C which is quite a big difference. Also, as pressure increases, melting points definitely do decrease, which is what allows Lake Vostok to remain (likely) in liquid form. Similarly, aquifers could exist at somewhat shallow (>1km) depths under Martian soil so long as the pressure exists. What would need to be determined then is, at what depth does this pressure exist? Secondly, I never brought up the gullies. I am fully aware of the current hypothesis surrounding them. I was at work when I posted that link and didn't have a chance to fully read it. I only posted it because it seemed to have some information that related to this topic and I apologize for it not suiting that goal entirely. -------------------- |
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Dec 8 2010, 05:19 AM
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#5
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Junior Member Group: Members Posts: 59 Joined: 12-November 09 Member No.: 5039 |
That isn't really all that true. Pressure can play a large part in the melting point, especially when you consider other factors such as water purity. Seawater for instance, freezes at -2C which is quite a big difference. Also, as pressure increases, melting points definitely do decrease, which is what allows Lake Vostok to remain (likely) in liquid form. I know. *In the context of current discussion*, though, +/- 2-3 degrees Celsius are not a big deal. Martian subsurface, even at equator, is at least -40 C, which is a deep freeze for water at any possible pressure or salinity. (BTW, I arrived at the figure of -40 C by googling up various data on internet, picking the highest one, and adding some margin, - I want to err on a safe side in this argument. The real figure may easily be -60 C). |
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