Comet 67P/Churyumov-Gerasimenko, studied in detail by the European Space Agency Rosetta and Philae spacecraft since September 2014, is a body with distinct and unexpected features. Now two astronomers have a radical explanation for its properties -- micro-organisms that shape cometary activity. Dr Max Wallis of the University of Cardiff set out their ideas today (Monday 6 July) at the National Astronomy Meeting in Llandudno, Wales.

Rosetta data have revealed an irregular 'duck shaped' comet with about 4.3 by 4.1 km in extent. It appears to have a black crust and underlying ice and images show large, smooth 'seas', flat-bottomed craters and a surface peppered with mega-boulders. The crater lakes are re-frozen bodies of water overlain with organic debris. Parallel furrows relate to the flexing of the asymmetric and spinning double-lobed body, which generates fractures in the ice beneath.

Dr Wallis, and his colleague Professor Chandra Wickramasinghe, Director of the Buckingham Centre for Astrobiology, argue that these features are all consistent with a mixture of ice and organic material that consolidate under the sun's warming during the comet's orbiting in space, when active micro-organisms can be supported.

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