Calcite differences on Mars

Differential thermal analysis of calcite samples is aiding the hunt for life on Mars. 

Differential thermal analysis involves heating a sample and an inert reference material to compare the temperature differences at which each degrades. Calcite from non-living sources degrades at a temperature 40?C higher than calcite produced by microorganisms, report researchers in France. The researchers hypothesise that analysing rocks collected on Mars could confirm the existence of life on the planet.

The researchers led by Fabien Stalport of the University of Paris analyzed a variety of calcite samples taken from around the globe representing specimens formed by microorganisms and also through non-living natural processes. 

’This method seems to be promising in the case of the search of past life on Mars because it does not require finding organic molecules that may have been destroyed over geologic time,’ said Stalport.

Robert Lodder, professor of chemistry at the University of Kentucky, US, has doubts about the technique being used on Mars. ’First of all, it depends on the likelihood of finding calcite on Mars, something that has not yet been shown,’ said Lodder. ’Also there is no evidence in their paper to support the hypothesis that a statistically significant difference exists between calcite that is biotic or abiotic in origin.’

Meanwhile, Stalport and his team continue to accumulate new data and will publish a paper later this year. 

Barry DiGregorio