Temperature and pressure at Gale, Suitable (for short periods) for liquid water? |
Temperature and pressure at Gale, Suitable (for short periods) for liquid water? |
Sep 30 2012, 03:23 PM
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Junior Member Group: Members Posts: 62 Joined: 11-July 11 Member No.: 6058 |
Just a quick query from someone with no background in science. Obviously, MSL has AFAIK not returned evidence of recent (i.e. years/decades) liquid water in its vicinity; however, I was interested by the following graphs:
08.21.2012: First Pressure Readings on Mars http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=4501 08.21.2012: Taking Mars' Temperature http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=4502 The first indicates that the pressure between 15 Aug and 18 Aug never dropped below c. 690 millibars; the second shows that, for a period of a couple of hours on 16 Aug, the temperature rose above freezing. If water had been present on the surface, then, would it have been liquid during this brief period? The pressure and temperature seemed to satisfy the conditions for liquid water as I understand them (indeed, the pressure seems to be high enough (just) on a 24-hour basis to allow for the presence of liquid water). Thanks in advance for your opinions (corroborative or not!) on this. |
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Sep 30 2012, 03:51 PM
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
I doubt that the pressure on the surface ever exceeds 10 mb, and that would be at the bottom of Valles Marineris and some portions of the Hellas basin.
6.9 mb for Gale is probably about as good as it gets, plus or minus a few tenths...therefore, no possibility of sustaining liquid water. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Sep 30 2012, 04:50 PM
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Junior Member Group: Members Posts: 85 Joined: 5-September 12 Member No.: 6635 |
I doubt that the pressure on the surface ever exceeds 10 mb, and that would be at the bottom of Valles Marineris and some portions of the Hellas basin. 6.9 mb for Gale is probably about as good as it gets, plus or minus a few tenths...therefore, no possibility of sustaining liquid water. The maximum surface pressure on mars occurs just after southern summer solstice. This is still many months away. At the Viking 2 site the average pressure at this time was near 10.2mb. The MSL site is another 2km or so LOWER than this. Using a scale height of 11km for mars suggest we might see pressures on the order of 11+ mb at this time compared to our current 7mb. Plugging in the numbers for Hellas (-8km) you can see that pressures can be as high as ~14mb. For those interested in a good introduction to the Martian atmosphere (with Viking data ) ...... "The Surface of Mars" by Michael J. Carr (1980) Yale University Press Still one of the best in my opinion |
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