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The surface of Mars might be rid of organic compounds.  (Source: Scrape TV)
Scientists propose new theory as to why we can't find organic organisms on the 'red planet'

The ongoing question as to why scientists cannot find organic material on the surface of Mars may be answered after all.

Published in the journal Astrobiology, the article is titled "Photocatalytic Decomposition of Carboxylated Molecules on Light-Exposed Martian Regolith and its Relation to Methane Production on Mars." Written by Ilya Shkrob, Sergey Chemerisov, and Timothy Marin, from Argonne National Laboratory and Benedictine University in Illinois, the three conclude that there may be no 'safe haven' for such organic molecules on Mars.

On Earth, plant-like organisms use photosynthesis to covert carbon and water into carbon dioxide. However, the opposite is proposed to happen on mars. The iron oxides, well known for giving the planet its red color, are photocatalysts. They use the ultraviolet light, absorbed through the Mars' thin atmosphere, as energy to oxidize organic compounds trapped in soil particles, thereby converting them to gases such as carbon dioxide and methane.

"This is an interesting result and may be an important step in solving the enduring mystery of organics on Mars," says Christopher McKay, "We see organics in many places in the solar system but have not been able to detect them on Mars--the planet that we think had the most Earth-like conditions. Why? Could it be our instrument approach has been wrong? Or could it be that there is some chemistry on Mars that is actively destroying organics? This work points toward this latter explanation."

He goes on to explain that Mars might have, in fact, a self cleaning surface, which means to find any evidence of carbon-containing molecules, astronauts will have to dig deep. McKay is the Senior Editor of Astrobiology and a Research Scientist at NASA Ames Research Center.

The authors suggest that instead of looking for organic organisms to prove life on Mars, other methods for determining life may have to be employed. In essence, many have been looking for something (proteins, amino acids, organic compounds) that was never there to begin with. It is now reasonable to suggest deep drilling tactics, that will dig up rocks and soils that have retained the preserved organics. With this new study, many hope we are one step closer to determining if life is, or ever was, present on the Martian planet.

Astrobiology is a peer-reviewed journal published by Mary Ann Liebert, Inc. The article is available online for free at The journal is published ten times a year in print and online.

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Hypothesis != Theory
By oTAL on 6/14/2010 11:32:21 AM , Rating: 2
I know this isn't a clear cut and it's not even very important.
But, the way I studied it, you propose an hypothesis, you and your colleagues test it out experimentally, and then if it holds up it becomes a theory.

Correct me if I'm wrong.

RE: Hypothesis != Theory
By geddarkstorm on 6/14/2010 1:47:02 PM , Rating: 3
Yes, that is exactly the scientific process. However, in layman language, hypothesis and theory are often interchanged, even if this is technically incorrect.

That said, it's already known that iron oxides destroy organics, and this can be done any time in a lab. For instance, this is part of why stepping on a rusty nail leads to tetanus (the iron oxide rust kills your surrounding tissues, into which the anaerobic bacteria Clostridium tetani can enter and surrvive, and begin producing toxin).

The fact it took so long for someone to propose this is what's kinda silly -- it's blatantly obvious chemistry and accounts for all known observations.

RE: Hypothesis != Theory
By JediJeb on 6/14/2010 4:30:33 PM , Rating: 2
Similar to a test we use in the laboratory to monitor for organic compounds, where you expose a sample to UV light and Sodium persulfate(strong oxidizer, others can be used) and the organic material turns into CO2 and you monitor the amount of CO2 released to calculate the amount of organic carbon present. It works in the lab under conditions I imagine are less severe than those on the Martian surface to this explanation makes perfect sense as to why we have not found organic molecules on Mars yet.

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