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#26 2004-02-21 07:00:33

Shaun Barrett
Member
From: Cairns, Queensland, Australia
Registered: 2001-12-28
Posts: 2,843

Re: 'smoking gun evidence that water was on Mars'

[color=#000000:post_uid4]One of Arthur C. Clarke's first books was called "The Sands of Mars". It's still one of my favourite books even though it is hopelessly dated now, portraying Mars as considerably more hospitable than we know it to be these days.
    In the book there were hardy leathery martian plants with pods, and slow moving animals which grazed on them. It turned out the pods were full of oxygen and the animals absorbed it by ingestion rather than inhalation.

    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.
                                         ???[/color:post_uid4]


The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

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#27 2004-02-21 08:55:05

Rxke
Member
From: Belgium
Registered: 2003-11-03
Posts: 3,658

Re: 'smoking gun evidence that water was on Mars'

[color=#000000:post_uid0]You have a point... Esp since Mars reeives a lot less insolation, energy must be conserved (and to make free O2, you need energy, so conserving that O2 as errr... fuel, would make sense, too...

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...[/color:post_uid0]


ExoMars' launcher's 2nd stage is probably en route to Mars. Unsterilised... yikes

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#28 2004-02-21 19:37:47

Shaun Barrett
Member
From: Cairns, Queensland, Australia
Registered: 2001-12-28
Posts: 2,843

Re: 'smoking gun evidence that water was on Mars'

[color=#000000:post_uid4]When I signed off on that last post, Rxke, I had a premonition you might mention Viking!
    I don't have a coherent hypothesis about the possible metabolic pathways in martian bacteria (assuming there are any, and I still think there are) because I simply don't know enough about microbiology.

    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?
                                             ???   smile[/color:post_uid4]


The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

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#29 2004-02-23 22:47:27

rgcarnes
Member
From: In the country near Rolla Miss
Registered: 2002-02-04
Posts: 111

Re: 'smoking gun evidence that water was on Mars'

[color=#000000:post_uid0]As Spirit is presently at the half way point to a real crater in a region where there are many land forms suggesting water, don't give up hope that there are interesting things which may be found by this probe yet. 

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.  [/color:post_uid0]


Rex G. Carnes

If the Meek Inherit the Earth, Where Do All the Bold Go?

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#30 2004-02-24 01:08:50

Shaun Barrett
Member
From: Cairns, Queensland, Australia
Registered: 2001-12-28
Posts: 2,843

Re: 'smoking gun evidence that water was on Mars'

[color=#000000:post_uid4]Fascinating idea, Rex.    smile

    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'.
                                                  cool[/color:post_uid4]


The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

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#31 2004-02-24 10:06:30

cassioli
Member
From: Italy
Registered: 2004-02-23
Posts: 218

Re: 'smoking gun evidence that water was on Mars'

[color=#000000:post_uid0]

[...]

    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?[/quote:post_uid0]

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?
[img:post_uid0]http://www.lyle.org/mars/imagery/thumbn … 61R1M1.JPG[/img:post_uid0]  (zoom)[/color:post_uid0]

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