Signs of life found on Saturn moon

Readings suggest microbes with unusual diet

NASA scientists have found evidence that could indicate life on one of Saturn's moons.

According to a report published today in New Scientist, the signatures have been spotted by the Cassini space probe – although scientists at NASA were quick to point out that they could also be the result of non-biological chemical reactions.

The scientists' interest stems from infra-red mapping of Titan's surface, which has revealed a lack of acetylene in the atmosphere. Readings also indicate lower-than-expected levels of hydrogen on Titan's surface.

In theory, the ultraviolet in sunlight should constantly trigger the production of acetylene in the moon's dense atmosphere. Scientists are now suggesting that it may be being 'eaten' by exotic microbes that swim about in the pools of methane and ethane on the moon's surface, breathing hydrogen.

Chris McKay of NASA's Ames Research Center in Moffett Field, and Heather R. Smith of the International Space University in Strasbourg, France, first calculated that microbes could survive in this way in 2005.

The readings now provided by the Cassini spacecraft suggest that their predictions may be borne out.

McKay told New Scientist that Cassini's measurements pointed to, "very unusual and currently unexplained chemistry", adding that it was "certainly not proof of life, but very interesting".