Mars may not be lifeless, say scientists
MEXICO CITY. September 7. KAZINFORM Carbon-rich organic molecules, which serve as the building blocks of life, may be present on Mars after all, say scientists - challenging a widely-held notion of the Red Planet as barren; Kazinform refers to BBC.
When Nasa's two Viking landers picked up and examined samples of Martian soil in 1976, scientists found no evidence for carbon-rich molecules or biology.
But after the Phoenix Mars Lander discovered the chlorine-containing chemical perchlorate in the planet's "arctic" region in 2008, scientists decided to re-visit the issue.
They travelled to the Atacama Desert in Chile, where conditions are believed to be similar to those on Mars.
After mixing the soil with perchlorate and heating it, they found that the gases produced were carbon dioxide and traces of chloromethane and dichloromethane - just like the gases released by the chemical reactions after the Viking landers heated the Martian soil more than three decades ago.
They also found that chemical reactions effectively destroyed all organic compounds in the soil.
"Our results suggest that not only organics, but also perchlorate, may have been present in the soil at both Viking landing sites," said the study's lead author, Rafael Navarro-González of the National Autonomous University of Mexico, Mexico City.
When scientists originally examined the data from the Viking probes, they interpreted the chlorine-containing organic compounds as contaminants from cleaning fluids carried on the spacecraft.
It is not yet clear whether the organic molecules are indigenous to the Red Planet or have been brought by meteorites.
This will be one of the goals of upcoming missions to Mars. In 2011, Nasa is planning to kick off its Mars Science Laboratory (MSL) mission, with the Curiosity rover designed to search for organic material on the planet; Kazinform cites BBC. See www.bbc.co.uk for full version.