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*I thought I was going to be posting this in the "Spirit & Opportunity *4*" thread, but nope...this particular finding is not due to either rover.
I'm copying and pasting from the text of "Science News astro bytes," a column feature for "Astronomy" magazine online (multiple short articles posted back-to-back):
"Red Planet peroxide
Thanks to the close passage of Earth and Mars's orbits in 2003, researchers were able to detect and measure the level of atmospheric hydrogen peroxide on the Red Planet. Although this confirms what scientists have long speculated, it marks the first time they have found a chemical catalyst in a non-Earth atmosphere. These observations were made using the James Clerk Maxwell Telescope atop Mauna Kea, Hawaii.
The key question now is how this finding will influence the search for life on Mars.
'Hydrogen peroxide is actually used as an antiseptic here on Earth, and so it would tend to retard any biological activity on the surface on Mars,' explains Todd Clancy of the Space Science Institute in Boulder, Colorado. 'For this reason, as well as the ultraviolet radiation, and lack of water, bacteria-like organisms are not expected to be viable on the surface.'
With this in mind, Clancy believes the search for martian life should concentrate on subsurface regions."
--Cindy
[http://www.astronomy.com/Content/Dynami … 2unvsg.asp]Link to entire "astro bytes," which contains above article
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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There's a lot of argument and counterargument on the whole peroxide issue from knowledgeable people and so I'm not certain what to think, really. While atmospheric survey scans may have detected eroxides in the atmosphere, IIRC, the levels were quite low. Also, Earth's atmosphere contains trace amounts of peroxide, expecially near cities whre photochemical interactions with smog generate it.
For a counterpoint to the preroxide arguments, go [http://mars.spherix.com/index.html]here. It's a webpage maintained by Dr. Levin, the designer of one of the original Viking life detection experiments. He's still maintaing that they detected life on Mars and presents some failry persuasive reasoning.
Personally, I'm dubious that life can survive in the upper few inches of Martian soil. There's a pretty good chance that life exists below the ground. The dust devil tracks on Olympus Mons you mentioned in another post are particularly persuasive for this as it indicates that MArs goes through periodic warmings that could have sustained microbial life.
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Is the existence of peroxides a topic for space-suit desiggn? Or is it not so aggressive for plastics?
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It depends on how much in the way of peroxide there is. It certainly doesn't pose an immediate threat. The higher UV levels certainly pose a greater threat to plastic. If peroxides do pose a threat, oxidation resistant platics such as polyethylene, polypropylene and teflon can be used.
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In response to your recent reference to Dr. Levin here, SBird, I'm glad someone else has taken his research on board and is prepared to at least doubt, if not discard, the official peroxide/superoxide hypothesis for Mars.
I've never been a fan of the official line and I tend to think the LR experiment did get a microbial reaction. I think the top few centimetres of martian soil, while not swarming with life, might still host small colonies of hardy bacteria. They may well spend most of their time in cold suspended animation, but there are probably times when liquid water and ambient temperatures allow metabolism to occur.
My guess is that the deeper you go, the more bacteria you'll find ... and more varieties perhaps as well.
I'm something of a Dr. Levin fan!
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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Having read Levin's stuff, I'm still leaning more towards the inorganic peroxide explanation. The rapid release of metabolites is much closer to what one would expect from plain chemistry than biology. However, I agree with Levin that we can't rule out life just yet.
The next mars rover is going to have an advanced amino acid detector that will also have the ability to resolve chirality. It should be able to settle things once and for all when it gets there in a few years.
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Is it even possible that there exist some life-form which can resist or even use the aggrassive peroxide-environment and even use the UV-light for a kind of fotosynthesis? I don't what are, for example, the chemical properties of silicon-derived materials in respect to this, but I could imagine some kind of life form based on SiO or maybe CF structures taht resist easily the peroxides and use the UV-light fruitfully.
And what about eg sulfur, zirkon?
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It's tough to even conveive of anything used bonds other than carbon. Si and S just are too metallic and two bulky respectively to be good at making complex molecules. Plus reactive oxygen molecules are really destructive.
Of course, that doesn't rule life out. Our own bodies handle pretty high levels of oxygen free radicals. Bacteria, however just don't deal with them very well given that there's not muc mass there to soak up the oxidative damage - we can easily lose a few skin cells but a bacteruim doesn't have that luxury.
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As far as we know, living things require carbon bonding to operate, no other atom will form stable molecules of arbitrary size easily... silicon hardly forms molecules at all except in certain cases. So, its unlikly that life exsists that operates via a totally different chemistry. The nasty UV radiation and oxygen radicals tend to attack molecules made of carbon in general, so I doubt we'll find anything in the top of the toil.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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