Both tropical and polar temperatures on Mars daily.

[exoscientist]

This site discusses that at the MER rover landing sites the maximum Summer-time air temperatures reached 30 C, 86 F, while the temperature swings from day to night reach a 100 C , 180 F, change:<br /><br />Extreme Planet Takes Its Toll.<br />June 12, 2007<br />Like Sun Belt retirees who complain about cold weather, NASA's Mars rovers are becoming less tolerant of temperature changes with age.<br />http://marsrovers.jpl.nasa.gov/spotlight/20070612.html<br /><br /> On this same page is discussed the observations of frost on the Opportunity rover. <br /> It had been known for some time that daytime, Summer temperatures can exceed the melting point of water at equatorial locations on Mars but it was believed the equator was desiccated.<br /> We now have visual evidence that the equator on Mars is not desiccated, in addition to the GRS/HEND instrument readings on Mars Odyssey showing this.<br /> The errors of the report of "puddles" at the Opportunity rover site have been legitimately criticized. But the observation of frost on the Opportunity rover occurred 3 years ago.<br /> Is not the refusal to investigate the possibility of liquid water at the Opportunity site when the environmental conditions suggest it should be possible an even greater error of omission by the scientific community at large?<br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>

 

[alexblackwell]

<i>Is not the refusal to investigate the possibility of liquid water at the Opportunity site when the environmental conditions suggest it should be possible an even greater error of omission by the scientific community at large?</i><br /><br />Don't you ever get tired standing on your soapbox?<br /><br />First of all, your question is based on a false premise. There is no "refusal to investigate the possibility of liquid water at the Opportunity site," especially given that the remote sensing instruments on the rovers are quite capable of indicating the <i>actual presence</i> of liquid water. The fact that liquid water is metastable on the martian surface has been known for quite some time. And in three years of observations at Meridiani, no data have shown current liquid water, a discovery that would have MER team members tripping over themselves to get to the podium.

 

[exoscientist]

There has been no theoretical investigation into the possibilities of liquid water specifically at the rover sites and the possible means it could be detected.<br /> Because it is expected to be metastable it would require a more incisive investigation to detect than a mere gross observation of a puddle. <br /> It is the fact that no such investigation has been proposed that I argue is an error of omission.<br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Thanks for the post. But it is well known by Mars scientists that at some low lying locations both the pressures and daytime temperatures are within the range to permit liquid water.<br /> The MER rover landing sites are within such zones.<br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>

 

[jaxtraw]

This is no doubt a stupid question, but I'm going to open myself to ridicule anyway-<br /><br />The fascination with liquid water ISTM is a proxy for fascination with current life on Mars. If there's water there may be life. But of course even if there is water, it doesn't mean there's life, so even discovery of a river running across Meridiani wouldn't tell us any more than that a river runs through it <img src="/images/icons/smile.gif" /> So while water would be an exciting discovery, it would only be a bit exciting.<br /><br />ISTM that the current vogue is looking for markers of- proxies for- life. Methane, for instance, but such things can never be conclusive. Viking's life experiment taught us that even when such a chemical reaction based experimental positive is found, it may not be life- and indeed virtually everybody agrees that that was a false positive.<br /><br />So- here's the naive question bit- why not stop looking for proxies- chemicals, basically- and instead look for life itself? Is there a reason that we can't fit a rover with a technologically feasible apparatus that digs up a soil sample and looks at it under a microscope? If it has cells in it (and surely any life must be composed of something like our own Earth life's cells) then we've got confirmation. If we can feed such microbial life some nutrients and watch it grow and even reproduce, so much the better!<br /><br />I know this is a naive question, but it seems to me it's the only way there'll ever be some kind of reliable confirmation, beyond speculation. <br /><br />What I'm getting at here is that while the chances may be small, it's at least an experiment wherein you only need to see one cell, and you've got proof positive...

 

[centsworth_II]

<font color="yellow">"Is there a reason that we can't fit a rover with a technologically feasible <br />apparatus that digs up a soil sample and looks at it under a microscope?"</font><br /><br />The Phoenix lander will be sitting on the surface of Mars doing exactly this<br />one year from now -- and in an area of the planet <b>known</b> to have large<br />amounts of (frozen) water. Granted, the purpose of the microscopic <br />investigations is to study the microscopic morphology of dust and crystals,<br />but that won't stop folks from looking for other things. <div class="Discussion_UserSignature"> </div>

 

[h2ouniverse]

And I hope that Exomars will find something too, after Phoenix, in 2013...

 

[centsworth_II]

Don't leave out MSL, landing in 2010. <div class="Discussion_UserSignature"> </div>

 

[h2ouniverse]

Oops<br />Sorry. <br />A hard thing for poor engineers on this side of the pond to be recalled that for any ESA spacecraft, there are 5 NASA ones. <br />If only I could cross this ocean...

 

[3488]

Hi Bob & AlexBlackwell.<br /><br />i think that you were referring to MER B Opportunity on the morning of Sol 257 (1), <br />& Sol 257 (2) just prior to sunrise.<br /><br />Yes it was an interesting observation.<br /><br />It does clearly show that the atmosphere in Meridiani, sometimes reaches the dew point.<br /><br />Do not forget, Viking 2 imaged frost at the Utopia Planitia site too.<br /><br />That is very true centsworthII. After all, that is partly the reason for why Mars Phoenix Lander is to <br />land in Scandia Colles.<br /><br />Lets hope it goes well, we can expect some real revelations from that site.<br /><br />I hope that a final landing site will be decided soon.<br /><br />Thank you Bob for starting this.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[exoscientist]

The microscopes on the Phoenix, Exomars, and MSL landers still would not be able to resolve individual microbes though. After a web search the Phoenix microscope will have a 16 micron resolution, the Exomars microscope, a 6 micron resolutions, and the MSL, a 4 micron resolution.<br /> To resolve microbes you would want to have at least 500 nm resolution.<br /><br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

<i>"The atomic force microscope will provide sample images down to <br /><b>10 nanometers</b> - the smallest scale ever examined on Mars. <br />Using its sensors, the AFM creates a very small-scale "topographic" <br />map showing the detailed structure of soil and ice grains."</i>]<br />http://phoenix.lpl.arizona.edu/science_meca.php<br /><br />I don't know what these "topographic maps" will look like, but topography<br />including sphere or rod shapes is sure to stimulate a lot of discussion.<br />The image at right below is about 4 micrometers or 4000 nanometers <br />wide. The 10 nanometer scale advertised for the Phoenix AFM would fit<br />400 times across that image! (If all my math is right.)<br /><br /><br /><br />http://www.nsf.gov/od/lpa/news/03/tip030103.htm<br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Attached below is a graph I use that shows the dates for solar longitude on Mars from 1997 to 2007. I copied this from some online report but now can't remember which one it was. Solar longitude tells the position of Mars in its orbit, 0°-90° is northern Spring; 90°-180° is northern Summer; 180°-270°, northern Autumn; and 270°-360°, northern Winter.<br />It is notable that Spirit landed in January, 2004 at the end of the period that the HEND instrument on Mars Odyssey indicates is the highest period of H2O deposition, Ls=270°-330°, which is early to mid Summer in the southern hemisphere:<br /><br />47 - EVIDENCE OF THE SEASONAL REDISTRIBUTION OF WATER<br />IN THE SURFICIAL MARTIAN REGOLITH BASED ON ANALYSIS OF<br />THE HEND MAPPING DATA.<br />R.O. Kuzmin, E.V. Zabalueva, I.G. Mitrofanov,<br />M.L.Litvak, A.V.<br />Parshukov, V.Yu.Grin'kov, W. Boynton, R.S. Saunders.<br />"As it well seen from fig.1b,c,d, two distinctive<br />"hollows" of neutrons flux reduction have been appeared<br />in the northern hemisphere during northern summer at<br />Ls=130°-170° and in first half of northern winter at<br />Ls=270°-330°, being extended from high to low<br />latitudes. At that, later "hollow" (Ls=270°-330°) is<br />characterized by much stronger reduction of the<br />neutrons flux and it traces from northern polar region<br />up to low latitudes in the southern hemisphere. The<br />first "hollow" is related with periods of the northern<br />middle summer, while the second one - with of the<br />southern middle summer. In both case the residual<br />polar caps serve as main source of the water in the<br />Martian atmosphere."<br />p. 2<br />http://www.geokhi.ru/~planetology/theses/47_kuzmin_et_al.pdf<br /><br />This is important because shortly after landing the Spirit rover observed material that might have been liquid water related, the famous "magic carpet":<br /><br />Mystery at Gusev Crater.<br /> <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

SULFATE-RICH SOILS EXPOSED BY SPIRIT ROVER AT MULTIPLE LOCATIONS IN GUSEV CRATER ON MARS.<br />Alian Wang1, Jim Bell III2, Ron Li3, Jeffrey R. Johnson4, William Farrand5, Raymond E. Arvidson1, Larry Crumpler6, Steven W. Squyres2, Ken Herkenhoff4, Amy Knudson1, Wei Chen3, and Athena team.<br />Seventh International Conference on Mars.<br />http://www.lpi.usra.edu/meetings/7thmars2007/pdf/3348.pdf<br /><br />This report gives evidence this time through PANCAM visible light wavelengths that sulfates are seasonally hydrated and dehydrated at the Spirit site.<br /><br />Bob Clark <div class="Discussion_UserSignature"> </div>

 

[3488]

Thanks Bob,<br /><br />When I get time later, I will read through your posts & links properly.<br /><br />Very interesting.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>