Possible present day habitats for life on Mars (Including potential Mars special regions): Difference between revisions
Possible present day habitats for life on Mars (Including potential Mars special regions) (edit)
Revision as of 10:09, 6 March 2021
, 3 years ago→Solid state greenhouse effect model
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[[File:JoekullsarlonBlueBlockOfIce.jpg|thumb|JoekullsarlonBlueBlockOfIce| 400px| Blue wall of an Iceberg on [[Jökulsárlón]], Iceland. On the Earth, [[Blue ice (glacial)|Blue ice]] like this forms as a result of air bubbles squeezed out of glacier ice. This has the right optical and thermal properties to act as a solid state greenhouse, trapping a layer of liquid water that forms 0.1 to 1 meters below the surface. In Möhlmann's model, if ice with similar optical and thermal properties forms on Mars, it could form a layer of liquid water centimeters to decimeters thick, which would form 5 - 10 cm below the surface.]]
In his model, first the ice forms a translucent layer - then as summer approaches, the solid state greenhouse effect raises the temperature of a layer below the surface to 0 °C, so melting it. This is a process familiar on the Earth for instance in Antarctica. On Earth, in similar conditions, the surface ice remains frozen, but a layer of liquid water forms from 0.1 to 1 meters below the surface. It forms preferentially in "blue ice".<ref>Nl, K., and T. SAND. [https://web.archive.org/web/20170322112720/http://www.igsoc.org:8080/journal/42/141/igs_journal_vol42_issue141_pg271-278.pdf "Melting, runoff and the formation of frozen lakes in a mixed snow and blue-ice field in Dronning Maud Land, Antarctica."], Journal of Glaciology, T'ol. 42, .\"0.141, 1996</ref>
On Mars, in his model, the melting layer is 5 to 10 cm below the surface. The liquid water layer starts off millimeters thick in their model, and can develop to be centimeters thick as the season progresses. The effect of the warming is cumulative over successive sols. Once formed, the liquid layer can persist overnight. Subsurface liquid water layers like this can form with surface temperatures as low as -56 °C.
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If the ice covers a heat absorbing layer at the right depth, the melted layer can form more rapidly, within a single sol, and can evolve to be tens of centimeters in thickness. In their model this starts as fresh water, insulated from the surface conditions by the overlaying ice layers - and then mixes with any salts to produce salty brines which would then flow beyond the edges to form the extending dark edges of the flow like features.
Later in the year, pressure can build up and cause formation of mini water geysers which may possibly explain the "white collars" that form around the flow like features towards the end of the season - in their model this is the result of liquid water erupting in mini water geysers and then freezing as white pure water ice.
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