Water ice in crater at Martian north pole.

[exoscientist]

Water ice in crater at Martian north pole.<br />http://www.esa.int/SPECIALS/Mars_Express/SEMGKA808BE_0.html<br /><br /> This is at 70 degrees North latitude. Temperatures can reach the melting point of water at 70 degrees South latitude:<br /><br />South Polar Cap Recession.<br />http://www.mars-ice.org/sp99.php<br /><br /> But how warm can it get at 70 degrees North latitude?<br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>

 

[robnissen]

Very cool. So where does this ice come from. It can't be left over from the wet period billions of years ago, at some time it would have melted. So is it comng up from an underground acquifer? Mars just keeps getting more interesting every day.

 

[bobvanx]

According to <br /><br />http://www-star.stanford.edu/projects/mgs/sum/s0503142140.html<br /><br />Not very warm. But I'm not finding the gloabl temp maps from THEMIS that I thought I'd be able to.

 

[bad_drawing]

What a fantastic pic.... There's something very intriguing about this.

 

[silylene old]

JonClarke first posted about this crater about 2 months ago, including the picture. We had a real good thread. I suggest searching back for it, it's a good read and will answer a lot of questions. <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>

 

[yurkin]

But the ESA article does have a nice little observation that was absent in the original story.<br /><br />That the ice may be on top of a layer of sand and the depth of the ice isn’t deep. That makes a lot more sense then the 30 feet deep layer of ice seems a lot more incredible then what might be just a millimeter or two of water ice on top of a large sand drift.<br />

 

[silylene old]

Yurkin, we speculated and discussed about just that possibility in the old thread a couple months ago. <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>

 

[exoscientist]

bobvanx, that link showed the radio occultation temperatures, which have greater error bars than infrared measurements. It gives the temperature as -91C. This is at 75 degrees North latitude though, rather than 70 degrees North.<br /> I'd like to see what the max temperature is at the crater's location.<br /><br /><br /> Bob Clark<br /> <div class="Discussion_UserSignature"> </div>

 

[bobvanx]

I don't know if you'll be able to get this ASU link to open:<br /><br />link to THEMIS map<br /><br />but it shows this crater in a global context. <br /><br />(edit)<br /><br />Here, this is better, but you can't tell there's any ice in it:<br /><br />http://themis-data.asu.edu/img/-V02381004.html

 

[bobvanx]

Here's a pic from the THEMIS site that <i>looks</i> like you can see "through" the surface, as though this were water.

 

[exoscientist]

This report shows modeled maximal temperatures on Mars according to latitude: <br /><br />Title: On the possibility of liquid water on present-day Mars. <br />Journal: Journal of Geophysical Research, Volume 106, Issue E10, p. 23317-23326 (JGR Homepage) <br />Publication Date: 10/2001 <br />http://www.agu.org/pubs/crossref/2001/2000JE001360.shtml <br /><br />It appears in Fig. 4 on page 23,231. The maximal temperature at 70 degrees North latitude is given as 250 C. <br />This is below the freezing point of pure water but is in the range for liquid water brines: <br /><br />Making a Splash on Mars. <br />"On a planet that's colder than Antarctica and where water boils at ten degrees above freezing, how could liquid water ever exist? Scientists say a dash of salt might help." <br />... <br />"One thing we have to be careful of is our everyday experience that <br />water always freezes at zero degrees," noted Hoover. "It doesn't. <br />Water containing dissolved salts freezes at a significantly lower <br />temperature. Don Juan Pond in Antarctica is a good example. It's a <br />high salinity pond with liquid water at temperatures as low as -24 ° <br />C." <br />http://science.msfc.nasa.gov/headlines/y2000/ast29jun_1m.htm <br /><br />Some images of Don Juan Pond: <br /><br />http://www.science.siu.edu/microbiology/Antarctica/images/DJP.view.JPeG <br /><br />http://www.science.siu.edu/microbiology/Antarctica/images/M2JC.DJP.JPEG <br /><br />Some reports argue there is no life in Don Juan Pond but this article discusses life on its periphery: <br /><br />An extraterrestrial habitat on Earth: the algal mat of Don Juan [correction of <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Bobvanx, do you have a link for that THEMIS image where the ice appears to be melted?<br /><br /><br /> Bob C. <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Some reports found active life at -20 C beneath Siberian permafrost in brines kept liquid by high salt content. This is within the maximal temperature range of the ice crater on Mars: <br /><br />It's A Cold Cruel Life. <br />"Summary (Dec 18, 2003): A microbe that exists in the coldest temperatures on Earth might provide clues about how a similar organism could survive beneath the Martian polar ice caps. In Siberian permafrost, the bacteria, named Psychrobacter cryopegella, can grow at -10 Celsius and can stay alive and even keep metabolizing at an astonishing -20 Celsius." <br />http://astrobio.net/news/article726.html <br /><br />Subfreezing Activity of Microorganisms and the Potential Habitability of Mars' Polar Regions. <br />Bruce M. Jakosky, Kenneth H. Nealson, Corien Bakermans, Ruth E. Ley, Michael T. Mellon <br />Astrobiology. Jun 2003, Vol. 3, No. 2: 343-350 <br />http://www.liebertonline.com/doi/abs/10.1089/153110703769016433 <br /><br />Supercooled Water Brines Within Permafrost - An Unknown Ecological Niche for Microorganisms: A Model for Astrobiology. <br />D. Gilichinsky, E. Rivkina, V. Shcherbakova, K. Laurinavichuis, J. Tiedje <br />Astrobiology. Jun 2003, Vol. 3, No. 2: 331-341 <br />http://www.liebertonline.com/doi/abs/10.1089/153110703769016424 <br /><br /><br />Bob Clark <div class="Discussion_UserSignature"> </div>