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 www.liebertpub.com/ast. The journal is published ten times a year in print and online.