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, 11:06 PM
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Junior Member Group: Members Posts: 40 Joined: 29-December 11 Member No.: 6295 |
Liquid water is almost impossible under the current conditions:
The enclosed phase diagrams of water and carbon dioxid state clearly that the triple point of H2O is around 6 mbar and 0 deg Celsius, while for CO2 it is 5.1 bar (not mbar !) and -56.5 deg Celsius. This means: below 0 deg Celsius water is solid (ice) at 6 mbar and CO2 is a gas. At 7 deg Celsius as on sol 52 and 6.9 mbar air pressure water theoretically could be a liquid but it is most probably a gas. And CO2 is a gas always. Cheers, Udo -------------------- But to be a lament on the lips of the loved one is glorious, For the prosaic goes toneless to Orcus below. (Friedrich Schiller: Naenie)
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