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Year in Review: Methane shortage on Mars

Trace of gas not enough to be sign of life

By
10:00am, December 26, 2013

A LITTLE GAS  The concentration of methane in the Martian atmosphere measured by the rover Curiosity is one ten-thousandth that on Earth. High levels of methane on Mars would have been a compelling indication of life there.

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After months of searching, the NASA rover Curiosity detected no appreciable methane in Mars’ atmosphere, disappointing scientists who had hoped to find a strong sign of life on the Red Planet.

On Earth, microbes have churned out as much as 95 percent of all atmospheric methane, so finding that gas in Mars’ air would have been solid circumstantial evidence of life. Instead, the rover measured no more than a trace of methane, with an average concentration of a mere 0.18 parts per billion (SN: 10/19/13, p. 7).

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