Further evidence for current liquid water near the equator on Mars.

[exoscientist]

Posted to sci.astro:<br /><br />From: rgregoryclark@yahoo.com (Robert Clark)<br />Newsgroups: sci.astro,alt.sci.planetary,sci.physics,sci.geo.geology,sci.geo.meteorology<br />Subject: Further evidence for current liquid water near the equator on Mars.<br />NNTP-Posting-Host: 141.158.40.198<br /><br />In this post to the Habitablezone.com/space/ bbs I discuss seasonal<br />changes observed by the Gamma Ray Spectrometer on Mars Odyssey in near<br />equatorial water on Mars:<br /><br />Latest Mars Odyssey observations prove free water at equator. <br />Posted by Robert Clark on 6/27/2003 8:03:48 AM.<br />http://www.habitablezone.com/space/messages/286216.html<br /><br /> A report presented to October, 2004 Vernasky/Brown Conference<br />provides further evidence of these seasonal changes:<br /><br />47 - EVIDENCE OF THE SEASONAL REDISTRIBUTION OF WATER IN THE SURFICIAL<br />MARTIAN REGOLITH BASED ON ANALYSIS OF THE HEND MAPPING DATA. R.O.<br />Kuzmin, E.V. Zabalueva, I.G. Mitrofanov, M.L.Litvak, A.V. Parshukov,<br />V.Yu.Grin'kov, W. Boynton, R.S. Saunders.<br />http://www.geokhi.ru/~planetology/theses/47_kuzmin_et_al.pdf <br /><br /> The authors note an increase in northern near equatorial regions of<br />the water content during the northern Summer and southern Summer. They<br />argue this should be due to transport of water vapor to the equator<br />from northern polar regions during northern Summer and from the<br />southern polar regions during southern Summer. Evidence for this is<br />its seasonal nature but also the fact the highest increase is shown in<br />the measurements closest to the surface. These are figures 1d and 1c,<br />which show the water content within 10cm (4 inches) and 20-30cm (8-12<br />inches), respectively. Note the highest increase in the measurements<br></br> <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Note that recent theoretical research suggests liquid water might <br />indeed be able to exist in some regions of Mars for short times:<br /><br />Meteorological Control on the Formation of Martian Paleolakes. <br />http://adsabs.harvard.edu/cgi-bin/bib_query?2000LPI....31.1509H<br /><br />Some of the areas were near the equator, however the authors ruled out equatorial areas because they were believed to be desiccated. This Mars Odyssey evidence suggests water does in fact exist near equator and therefore could become liquid for short periods seasonally:<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[silylene old]

exoscientist: The R.M. Haberle paper is actually a conservative estimate, since it assumes pure water ices and and lakes. If the water is briney or sulfurous, I would expect that the number of days with liquid water could be significantly greater with a slower evaporation rate. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[alokmohan]

Whether mars ever had water or methane is to be accurately known.We are too prone to think of life in mars.

 

[exoscientist]

Alex Blackwell posted a link to some freely available journal articles on Mars:<br /><br />Planetary and Space Science Volume 52, Issues 1-3, Pages 1-257, <br />Special issue: "Exploring Mars Surface and its Earth Analogues." <br />http://makeashorterlink.com/?C11835017<br /><br /><br />One of the articles calculates how deeply above freezing temperatures might penetrate the martian soil. This is important since it relates to whether the melting point might be reached if ice for example is several centimeters subsurface:<br /><br />Theoretical prediction of the thermal conductivity and temperature variation inside mars soil analogues. <br />F. Gori, and S. Corasaniti <br />Planetary and Space Science <br />Volume 52, Issues 1-3 , January-March 2004, Pages 91-99<br /><br />Two graphs in this paper gives the depth to temperature variations for both dry soil and frozen soil.<br /><br />The graph for dry soil is given in the first figure below. The second figure below gives the graph for frozen soil.<br />The graph for frozen soil shows above freezing temperatures can be reached more than 20cm, 8", subsurface, starting with a temperature of 298K at the surface.<br />Actually the melting point should be reached at even lower depths than this because the minimum temperature the authors use is 148K. Apparently they take this from the minimum Summer temperature anywhere on Mars. <br />However, an LPI report models the surface temperature range at the Pathfinder site, which is near the equator, and gives the range as about 190K to 290K, for a variation of 100K:<br /><br />The Martian Surface Boundary Layer. <br />Authors: Wilson, G. R.; Joshi, M. <br />Journal: 31st Annual Lunar and Planetary Science Conference, March 13-17, <br />2000, Houston, Texas, abstract no. 1678 <br />http://www.lpi.usra.edu/meetings/lpsc2000/pdf/1678.pdf<br /><br />This would b <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Graph of temperature variation for iced filled soil. <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Modeled temperatures at Pathfinder site.<br /><br />Bob Clark <div class="Discussion_UserSignature"> </div>