Do Martians exist?

Minerals may provide an answer

Published: Saturday 04 July 2015

-- (Credit: NASA)evidence suggests that Mars once had water on its surface, a denser atmosphere and a mild climate -- conditions favourable for life. But Viking Landers (i and ii) could not find any organic molecules when they studied Mars' soil in the 1970s. Now, researchers led by Fabien Stalport of Universit Paris XII in France contend that analysis of minerals would be a better approach. They say that inorganic compounds tend to survive longer than their organic counterparts and may also act as "tracers of biological activity" (Geophysical Research Letters, Vol 32, No 24, December, 2005).

The researchers studied the properties of calcite -- crystallised form of carbonate -- which could be expected on Mars because of presence of water and carbon dioxide. Calcite can be produced by abiotic as well as by biological activity. But biotic samples start degrading at a temperature 40 c lower than the abiotic ones. "This result is encouraging for a possible preservation of mineral biotic calcite structures on Mars for billions of years," the authors wrote. Consequently, future probes can be equipped for in situ study whether minerals had been formed by biological activity. The us plans to launch the Mars Science Laboratory in 2009.

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