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Your point about the lack of chemical evidence for a martian biosphere is a very good one and it's bothered me for a long time. A strong sequence of logical steps has led me to believe a sterile Mars is virtually an impossibility. But if there is life, and if it is essentially made of the 'same stuff' as terrestrial life, where are the chemical markers of its existence?
Each time I look at the outcrop Opportunity is looking at, I ask myself: what evidence of a past life (even civilzed form) could remain on a planet with atmosphere, after about 1 or 2 million (billion?) years later?
Maybe no direct evidence of lifeforms, but... what would it look like a modern cement building on the earth, after 2 million of years?
Just like... this?
[http://www.lyle.org/mars/imagery/1P1296 … 1.JPG.html](zoom)
I've been anxious to see the inside of that big crater for quite a while now but you've raised the excitement levels a few notches with your 'micro-climate hypothesis'.
Consider that an atmosphere boundary layer containing water vapor only a meter or so thick, if present, would imply that something as low as a crater wall could contain a small localized climate(potentially biosphere) and separate it from the area outside such a barrier.
I'm still holding out hope for an optically detectable surface layer. After all, with earth's atmosphere having a rule of thumb index of refraction of about 1.003, and vacuum having an index of 1.0000... (by definition), one can still see the reflective mirages over a sun warmed highway on earth caused by boundary conditions which must be changes within that .003 difference.
There are still images from the panorama camera which seem to me to indicate near surface currents in the atmosphere at least similar in magnitude to those observed by pathfinder when it detected the "dust devils" as seen in some of it's enhanced images in NASA's archives. It doesn't seem to be provable yet, but its very tantalizing to me.
]]> Your point about the lack of chemical evidence for a martian biosphere is a very good one and it's bothered me for a long time. A strong sequence of logical steps has led me to believe a sterile Mars is virtually an impossibility. But if there is life, and if it is essentially made of the 'same stuff' as terrestrial life, where are the chemical markers of its existence?
I can't abandon the concept of a martian biosphere because, at least to me, the logic is just too compelling. So that leaves me with the task of finding an explanation for the lack of tell-tale metabolites in the martian environment.
Maybe the metabolites are actually there but in low concentrations due to the population of bacteria in the regolith being very small by Earthly standards. Maybe we simply haven't looked hard enough(?).
A second possibility is the one I mentioned in my last post, that the organisms on Mars are extraordinarily frugal, guarding and conserving every scrap of carbon, oxygen, hydrogen and nitrogen they can find.
But then, Dr. Gilbert Levin's (in)famous Labeled Release Experiment (LR) on both Viking landers produced data consistent with a flurry of metabolic activity by martian soil bacteria. The evidence took the form of a large release of radioactively-labelled volatiles.
If my martian organisms are so economical and thrifty with such compounds, why did they release such large amounts with such frivolous abandon?!
Perhaps the answer lies in what you suggested, Rxke. The sudden introduction of so much relatively hyposaline water, may have disrupted the organisms' metabolism and cell structure fatally. But maybe they first gorged themselves on the fresh water and nutrient, uncharacteristically releasing large volumes of volatiles, before sef-destructing(?).
I realise what a long line of baseless speculation my arguments represent but I think it's a good thing to put hypotheses 'out there' for others to criticise.
Have we looked hard enough for trace amounts of gaseous metabolites in the martian air? Is there perhaps a scaled-down version of Gaia at work in the martian regolith? Can exotic superoxides exist in soils which are moist with brine, or were the Viking LR results our first data on martian metabolism at work? Did we effectively 'drown' a few thousand dry-adapted halophilic martian organisms in fresh water?
Any thoughts?
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another thing i think about: Viking didn't find conclusive evidence for life. But if this is a 'brine-world,' the Viking 'nutritional soup' used in the experiments could've killed organisms (halophiles) by adding not enough salt... Halophiles on erath start swelling and rip apart after a while in clean water, (membrane principle) this could've happened on Mars, too... the initial results showed activity, but it stopped...
]]> The point I'm making is in response to Rxke's comment about the lack of gaseous signatures of life in the martian air, though I'm not yet certain such signatures are entirely absent.
Is it not possible that organisms on Mars have gradually adapted to a situation in which the waste of volatiles like oxygen, methane, etc., is simply not an option? Perhaps the surviving life forms, used to long periods of deprivation, have developed metabolisms which store almost everything in order to 'trade' it in symbiotic relationships with other organisms.
We really should avoid the temptation to assume that the habits of terrestrial organisms will necessarily be duplicated by any we find on Mars. The conditions are very different between the two planets and we must be ready for surprising survival adaptations.
We are fortunate to live on a bountiful planet where the living is easy and we can afford to throw things away. I doubt martian microbes can afford to be as cavalier.
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One remark: if all these things turn out to be true, would that not kind of prove there is *no* life? If there is so much liquid water near the surface, and yet no traces of life to be seen... Or metabolisation gasses, like free O2, methane...
]]>One of the first (other than those seen during the Viking missions) images of these streaks was of the interior of a crater about 6 degrees south of the martian equator. They made an anaglyph image made up from an image made during the Mars Global Surveyor air braking period and an image made somewhat later.
I became convinced that the streaks were water based when I noticed that there were subtle indications of significant meandering features at the ends of some of the streaks, and also structures, similar to the hot spring deposited canopies found at Sitting Bull Falls in Lincoln National Forest in New Mexico, were noticable at or near their origins high on the crater walls.
]]>had to rotate it 180 deg to get it 'right' again (something wrong with my brain, i see hills instead of craters, and can't make the switch, mentally...)
lower down on the pic there are similar things like that, longer, a bit more sinuous. On the 'opposite side of another pit, so it is not a shadow (?)
Amazing landscape, those pits... Remember having seen something like that in real life in Germany, a giant depression, stripped of all plant life... eerie silence, now and then you could hear bits of rock tumbling down... was too young then to remember today what causes this.
there must be 'something' taking away material down those pits, but what? Most logical explanation would be water, but i really don't know?
Where are the rock-hounds in this forum?
]]>If you look at the upper portion, about 3/4 of an inch (2-3cm) from the top, you will see a long dark splotch running down the side of a hill. The coloration is unique when compared to the rest of the landscape, and it seems to be running downhill.
If I had to guess, I would say it was water, or the marks of water... or is it just shadows?
[http://images.spaceref.com/news/2004/20 … 300250.gif]http://images.spaceref.com/news/2004/20 … 300250.gif
I think I have seen other pictures like this, or at least others have made claims that similar signs have been found elsewhere on Mars. Am I just seeing this?
]]>All the science aboard seems like the Odyssey science payload, exception of the 3d color camera, but I think the most exciting instrument might be MARSIS :
(taken from MArs express web site)
MARSIS Sub-Surface Sounding Radar Altimeter
MARSIS will map the sub-surface structure to a depth of a few kilometres. The instrument's 40-metre long antenna will send low frequency radio waves towards the planet, which will be reflected from any surface they encounter.
For most, this will be the surface of Mars, but a significant fraction will travel through the crust to be reflected at sub-surface interfaces between layers of different material, including water or ice....
probing the first kms of martian subsurface with a 40 meters long antenna, wow !
Imagine, some people have argued that the martian crust is spongious, made of bubbles or huge caves, filled with water maybe...
Brief terminology question:
How can a petrified and exumed "gun" be still smoking?
Cause it's that cool.. d'uh! :-)
Just because it's old it still likes Camels.
hmm, I would try to think up 8 more, but I can guarantee they would only get worse, and considering how bad these are.... I will stop.
Good point, Rex.
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