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Martian Hydrology
ngunn
post Nov 23 2010, 08:46 PM
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An interesting article from Space Daily today: http://www.marsdaily.com/reports/Shallow_G...n_Mars_999.html
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ZLD
post Dec 7 2010, 08:06 PM
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And most people forget that the ground has pressure as well. wink.gif

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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Den
post Dec 8 2010, 02:19 AM
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QUOTE (ZLD @ Dec 7 2010, 09:06 PM) *
And most people forget that the ground has pressure as well. wink.gif

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

Attached Image


I know it is far from being scientific, but still...
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ZLD
post Dec 8 2010, 03:47 AM
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QUOTE (Den @ Dec 8 2010, 03:19 AM) *
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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Den
post Dec 8 2010, 05:19 AM
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QUOTE (ZLD @ Dec 8 2010, 04:47 AM) *
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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Posts in this topic
- ngunn   Martian Hydrology   Nov 23 2010, 08:46 PM
- - marsbug   How big would such an aquifer need to be to be pic...   Nov 27 2010, 08:53 PM
- - ngunn   I'm curious about this too, and my ignorance o...   Nov 27 2010, 09:18 PM
- - marsbug   A very quick bit of reading tells me that SHARAD h...   Nov 27 2010, 09:45 PM
- - ngunn   We know that Mars has plenty of H2O, and that like...   Nov 27 2010, 10:14 PM
|- - Den   QUOTE (ngunn @ Nov 27 2010, 11:14 PM) We ...   Dec 7 2010, 06:39 PM
- - ZLD   Quoting the Wikipedia entry on Martian Climate: Q...   Dec 7 2010, 07:15 PM
|- - Den   QUOTE (ZLD @ Dec 7 2010, 08:15 PM) Quotin...   Dec 8 2010, 02:00 AM
- - djellison   Den and ZLD - you're both forgetting one vital...   Dec 7 2010, 07:26 PM
|- - Den   QUOTE (djellison @ Dec 7 2010, 08:26 PM) ...   Dec 8 2010, 02:03 AM
- - ZLD   And most people forget that the ground has pressur...   Dec 7 2010, 08:06 PM
|- - Den   QUOTE (ZLD @ Dec 7 2010, 09:06 PM) And mo...   Dec 8 2010, 02:19 AM
|- - ZLD   QUOTE (Den @ Dec 8 2010, 03:19 AM) Water ...   Dec 8 2010, 03:47 AM
||- - Den   QUOTE (ZLD @ Dec 8 2010, 04:47 AM) That i...   Dec 8 2010, 05:19 AM
|- - ElkGroveDan   QUOTE (Den @ Dec 7 2010, 06:19 PM) Meltin...   Dec 8 2010, 05:11 AM
- - djellison   That paper is 10 years old, and many other studies...   Dec 7 2010, 08:54 PM
- - ZLD   I remember a while back spirit recording a tempera...   Dec 8 2010, 05:53 AM
|- - Den   QUOTE (ZLD @ Dec 8 2010, 06:53 AM) I reme...   Dec 8 2010, 11:21 AM
- - machi   Phase transitions (for example melting) of all che...   Dec 8 2010, 03:44 PM
- - sariondil   For those with access to 'Icarus': Articl...   Dec 8 2010, 04:15 PM
- - Fran Ontanaya   Is brine lost so fast to evaporation in those cond...   Dec 8 2010, 06:00 PM
- - ZLD   QUOTE Conclusions - The presence of salts on and i...   Dec 8 2010, 07:48 PM
- - ngunn   Thanks for the link. A good read indeed.   Dec 8 2010, 08:32 PM
- - marsbug   Thanks for that, its a good resource for anyone tr...   Dec 9 2010, 01:38 AM
- - sariondil   Another paper on modelling of subsurface water. Ag...   Dec 9 2010, 09:23 PM
|- - ngunn   QUOTE (sariondil @ Dec 9 2010, 09:23 PM) ...   Dec 9 2010, 09:45 PM
|- - djellison   QUOTE (sariondil @ Dec 9 2010, 01:23 PM) ...   Dec 9 2010, 09:48 PM
- - ngunn   The way we are just now I supose censorhip is an i...   Dec 10 2010, 12:11 AM
- - helvick   Much as I might be rabidly opposed to Elsevier...   Dec 10 2010, 12:43 AM
- - ElkGroveDan   I have to agree with Helvick.   Dec 10 2010, 01:19 AM
- - imipak   A reminder of the the discussion of the notorious...   Dec 17 2010, 02:30 PM


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