Potentially habitable flow-like features from Martian dry ice geyser dune spots: Difference between revisions
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[[File:Flow-like-features detail.gif|thumb|Flow-like-features detail|Flow-like features on Dunes in Richardson Crater, Mars [http://www.google.co.uk/mars/#q=Richardson%20crater&zoom=2 (Richardson crater in Google Mars)]. They form around the dark dune spots, in the debris of the hypothesized [[Martian Geysers]]. The dark material at the end of the flows moves at between 0.1 and 1.4 m/day in late spring / summer on Mars. This example moves approximately 39 meters in 26 days between the last two frames.<br><br>The two main models involve liquid water - either interfacial layers, or else layers of water created through the solid state greenhouse effect. <ref name="MartínezRenno2013">{{cite journal|url=https://link.springer.com/article/10.1007%2Fs11214-012-9956-3/fulltext.html|last1=Martínez|first1=G. M.|last2=Renno|first2=N. O.|title=Water and Brines on Mars: Current Evidence and Implications for MSL|journal=Space Science Reviews|volume=175|issue=1-4|year=2013|pages=29–51|issn=0038-6308|doi=10.1007/s11214-012-9956-3}}</ref><ref name=Kereszturi2008>Kereszturi, A., et al. [http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1555.pdf "Analysis of possible interfacial water driven seepages on Mars"], Lunar and Planetary Science Conference. Vol. 39. 2008.</ref><ref name="MartínezRenno2013">{{cite journal|url=https://link.springer.com/article/10.1007%2Fs11214-012-9956-3/fulltext.html|last1=Martínez|first1=G. M.|last2=Renno|first2=N. O.|title=Water and Brines on Mars: Current Evidence and Implications for MSL|journal=Space Science Reviews|volume=175|issue=1-4|year=2013|pages=29–51|issn=0038-6308|doi=10.1007/s11214-012-9956-3}}</ref><br><br>Animation centered on {{coord|72.02|S|179.408|E|globe:Mars}} [http://www.google.co.uk/mars/#lat=-72.02&lon=179.408&zoom=7 (location in Google Mars)]. Displayed region 188.5 meters by 172 meters. Dates of sequence: 19 January (sol 396), 24 January (sol 401), 29 January (sol 406), 10 February (sol 418), and 09 March (sol 444), all in 2009. All taken between 4.10 pm and 4.28 pm in Mars local time.]] |
[[File:Flow-like-features detail.gif|thumb|Flow-like-features detail|Flow-like features on Dunes in Richardson Crater, Mars [http://www.google.co.uk/mars/#q=Richardson%20crater&zoom=2 (Richardson crater in Google Mars)]. They form around the dark dune spots, in the debris of the hypothesized [[Martian Geysers]]. The dark material at the end of the flows moves at between 0.1 and 1.4 m/day in late spring / summer on Mars. This example moves approximately 39 meters in 26 days between the last two frames.<br><br>The two main models involve liquid water - either interfacial layers, or else layers of water created through the solid state greenhouse effect. <ref name="MartínezRenno2013">{{cite journal|url=https://link.springer.com/article/10.1007%2Fs11214-012-9956-3/fulltext.html|last1=Martínez|first1=G. M.|last2=Renno|first2=N. O.|title=Water and Brines on Mars: Current Evidence and Implications for MSL|journal=Space Science Reviews|volume=175|issue=1-4|year=2013|pages=29–51|issn=0038-6308|doi=10.1007/s11214-012-9956-3}}</ref><ref name=Kereszturi2008>Kereszturi, A., et al. [http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1555.pdf "Analysis of possible interfacial water driven seepages on Mars"], Lunar and Planetary Science Conference. Vol. 39. 2008.</ref><ref name="MartínezRenno2013">{{cite journal|url=https://link.springer.com/article/10.1007%2Fs11214-012-9956-3/fulltext.html|last1=Martínez|first1=G. M.|last2=Renno|first2=N. O.|title=Water and Brines on Mars: Current Evidence and Implications for MSL|journal=Space Science Reviews|volume=175|issue=1-4|year=2013|pages=29–51|issn=0038-6308|doi=10.1007/s11214-012-9956-3}}</ref><br><br>Animation centered on {{coord|72.02|S|179.408|E|globe:Mars}} [http://www.google.co.uk/mars/#lat=-72.02&lon=179.408&zoom=7 (location in Google Mars)]. Displayed region 188.5 meters by 172 meters. Dates of sequence: 19 January (sol 396), 24 January (sol 401), 29 January (sol 406), 10 February (sol 418), and 09 March (sol 444), all in 2009. All taken between 4.10 pm and 4.28 pm in Mars local time.]] |
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These |
These features near the Martian polar regions are associated with the [[Geyser (Mars)|Martian Geysers]]. Before they were well understood, there was a lot of speculation about what they might be. They resemble trees and vegetation, and in 2001 looking at the Mars Global Surveyor images, Arthur C. Clarke called them "Banyan trees"<ref name=Foulke2001>Nicole Foulke, [https://www.popsci.com/military-aviation-space/article/2001-12/banyan-trees-mars The Banyan trees of Mars], Popular science e-mail interview with Arthur C. Clarke, December 17, 2001</ref>, saying, only half joking "I'm now convinced that Mars is inhabited by a race of demented landscape gardeners,"<ref name=ClarkeSmithsonian2001>Arthur C. Clarke, speaking by teleophone for the [http://www.martianspiders.com/Sir%20Arthur%20C_%20Clarke%20at%20the%20Smithsonian,%20June%202001.htm Wernher von Braun Memorial Lecture], Smithsonian institute's National Air and Space Museum, June 6, 2001 - reported by John C. Sherwood</ref> [[File:High resolution image of Arthur C. Clarke's "Banyam tress of Mars".jpg|100px|In 2001 Arthur C. Clarke speculated that this was Martian vegetation similar to banyan trees. They are now thought to be dust carried in CO2 from dry ice Martian "geysers"]] |
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These are probably dry ice effects. Subsurface layers of dry ice are heated by the sun through the solid state greenhouse effect, and erupt as CO2 gas. The dark streaks and spots are thought to be debris from the geysers. |
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However, later in the year dark streaks |
However, later in the year dark streaks gradually extend down the slopes from the dark spots, sometimes at a rate of meters per day. These are the "flow-like features" that may be associated with liquid brines. There are streaks in both hemispheres but the details of how they form differ. |
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In the Southern hemisphere, both of the current models for this part of the process involve liquid water. In one of these models the features from initially as fresh water at 0 °C below clear ice in a solid state greenhouse effects. The other model involves thin layers of ULI water (undercooled liquid water) which form on the surface of solar heated grains, then flows downwards, supplying several litres of water per day to the features. In both cases they then pick out salts which let them remain liquid in the cold near surface conditions as they flow down the slopes. |
In the Southern hemisphere, both of the current models for this part of the process involve liquid water. In one of these models the features from initially as fresh water at 0 °C below clear ice in a solid state greenhouse effects. The other model involves thin layers of ULI water (undercooled liquid water) which form on the surface of solar heated grains, then flows downwards, supplying several litres of water per day to the features. In both cases they then pick out salts which let them remain liquid in the cold near surface conditions as they flow down the slopes. |
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