Potentially habitable flow-like features from Martian dry ice geyser dune spots: Difference between revisions
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Potentially habitable flow-like features from Martian dry ice geyser dune spots (edit)
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For details see the Dark Dune Spots section of Nilton Renno's paper<ref name="MartínezRenno2013DarkDuneSpots"/> which also has images of the two types of feature as they progress through the season.
==Earlier hypotheses==
[[Image:DDS MSO.jpg|thumb|right|200px|DDS-MSO hypothesis.]]
IN 2003 a team of Hungarian scientists proposed that the dark dune spots and channels may be colonies of [[photosynthesis|photosynthetic]] Martian microorganisms, which over-winter beneath the ice cap, and as the [[sunlight]] returns to the pole during early spring, light penetrates the ice, the microorganisms photosynthesise and heat their immediate surroundings. A pocket of liquid water, which would normally evaporate instantly in the thin Martian atmosphere, is trapped around them by the overlying ice. As this ice layer thins, the microorganisms show through grey. When it has completely melted, they rapidly desiccate and turn black surrounded by a grey aureole.<ref name=Andras /><ref>{{Cite book| author=Pócs, T. |author2=A. Horváth |author3=T. Gánti |author4=Sz. Bérczi |author5=E. Szathmáry |title=ESA SP-545 - Possible crypto-biotic-crust on Mars?| publisher=European Space Agency| date=2003| url=http://www.colbud.hu/esa/publications/28CBC8ESASP-545pp265-266.pdf| format=PDF| accessdate=24 November 2008 }}</ref><ref>{{cite journal|title=Dark Dune Spots: Possible Biomarkers on Mars?|journal=Origins of Life and Evolution of Biospheres|date=31 October 2003 |first=Tibor|last=Gánti|author2=András Horváth |author3=Szaniszló Bérczi |author4=Albert Gesztesi |author5=Eörs Szathmáry |volume= 33|issue=s 4–5|pages=515–557|doi=10.1023/A:1025705828948|url=http://www.springerlink.com/content/ut8r78131173254n/|accessdate=18 November 2008 }}</ref><ref>{{Cite journal|author=Pócs, T. |author2=A. Horváth |author3=T. Gánti |author4=S. Bérczi |author5=E. Szathmáry |title=38th Vernadsky-Brown Microsymposium on Comparative Planetology - Are the dark dune spots remnants of the crypto-biotic-crust of Mars? |place=Moscow, Russia |date=27–29 October 2003 |url=http://www.colbud.hu/esa/publications/26MosCBC10color.pdf |format=[[PDF]] |accessdate=7 September 2009 |deadurl=yes |archiveurl=https://web.archive.org/web/20110721104952/http://www.colbud.hu/esa/publications/26MosCBC10color.pdf |archivedate=21 July 2011 |df=dmy }}</ref> The Hungarian scientists think that even a complex sublimation process is insufficient to explain the formation and evolution of the dark dune spots in space and time.<ref name=Planetary /><ref>{{cite web|url=http://www.monochrom.at/dark-dune-spots/ |title=Dark Dune Spots – Could it be that it’s alive? |accessdate=4 September 2009 |author=András Sik |author2=Ákos Kereszturi |publisher=Monochrom }} (Audio interview, MP3 6 min.)</ref>
Science fiction writer [[Arthur C. Clarke]] promoted these formations as deserving of study from an [[astrobiology|astrobiological]] perspective.<ref name=Orme>{{cite journal|title=Marsbugs |journal=The Electronic Astrobiology Newsletter |date=9 June 2003 |first=Greg M. |last=Orme |author2=Peter K. Ness |volume=10 |issue=23 |page=5 |url=http://www.lyon.edu/projects/marsbugs/2003/20030609.pdf |accessdate=6 September 2009 |deadurl=yes |archiveurl=https://web.archive.org/web/20090327135109/http://www.lyon.edu/projects/marsbugs/2003/20030609.pdf |archivedate=27 March 2009 }}</ref>
In 2009 a multinational European team suggested that if liquid water is present in the spiders' channels during their annual defrost cycle, the structures might provide a niche where certain microscopic life forms could have retreated and adapted while sheltered from [[Ultraviolet|UV]] solar radiation.<ref name=Manrubia /> British and German teams also consider the possibility that [[organic matter]], [[microbe]]s, or even simple plants might co-exist with these inorganic formations, especially if the mechanism includes liquid water and a [[Geothermal gradient|geothermal]] energy source.<ref name=Ness /><ref>{{cite journal|title=Temporary liquid water in upper snow/ice sub-surfaces on Mars? |journal=Icarus|date=13 November 2009 |last1=Möhlmann |first=Diedrich T.F. |doi=10.1016/j.icarus.2009.11.013 |url=https://www.sciencedirect.com/science/article/pii/S0019103509004539|volume=207 |pages=140 |bibcode=2010Icar..207..140M}}</ref> However, they also remarked that the majority of geological structures may be accounted for without invoking any organic "life on Mars" hypothesis.<ref name=Ness /> (See also: [[Life on Mars (planet)|Life on Mars]].)
== See also==
* [[Possible present day habitats for life on Mars]]
==References==
{{Reflist}}
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