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Hot Topic Solar System Meteorites, Comets and Asteroids Life in Comets
 
Life in Comets
Based on a Cardiff University news release
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Meteorites, Comets and Asteroids
Posted:   08/19/07

Summary: A new scientific paper claims that recent probes inside comets show it is overwhelmingly likely that life began in space.

Comet Probes Reveal Evidence of Origin of Life, Scientists Claim

Deep Impact probe.
Credit: NASA

Researchers at Cardiff University believe that recent probes inside comets show it is overwhelmingly likely that life began in space.

Professor Chandra Wickramasinghe and colleagues at the University’s Centre for Astrobiology have long argued the case for panspermia - the theory that life began inside comets and then spread to habitable planets across the galaxy. It is a controversial topic, but highly relevant for astrobiologists trying to understand the origin of life and potential for life on other planets. A recent BBC Horizon documentary traced the development of the theory.

The team from Cardiff claims that findings from space probes sent to investigate passing comets reveal how the first organisms could have formed.

This spectacular image of comet Tempel 1 was taken 67 seconds after it obliterated Deep Impact's impactor spacecraft.
Credit: NASA/JPL-Caltech/UMD

The 2005 Deep Impact mission to Comet Tempel 1 discovered a mixture of organic and clay particles inside the comet. One theory for the origins of life proposes that clay particles acted as a catalyst, converting simple organic molecules into more complex structures. The 2004 Stardust Mission to Comet Wild 2 found a range of complex hydrocarbon molecules - potential building blocks for life.

The Cardiff team suggests that radioactive elements can keep water in liquid form in comet interiors for millions of years, making them potentially ideal “incubators” for early life. They also point out that the billions of comets in our solar system and across the galaxy contain far more clay than the early Earth did. The researchers calculate the odds of life starting on Earth rather than inside a comet at one trillion trillion (10 to the power of 24) to one against.

Professor Wickramasinghe said: “The findings of the comet missions, which surprised many, strengthen the argument for panspermia. We now have a mechanism for how it could have happened. All the necessary elements - clay, organic molecules and water - are there. The longer time scale and the greater mass of comets make it overwhelmingly more likely that life began in space than on earth.”

An artist impression of Stardust's close encounter with Wild-2.
Credit: JPL

The new paper, The Origin of Life in Comets, by Professor Wickramasinghe, Professor Bill Napier and Dr Janaki Wickramasinghe is to be published by the International Journal of Astrobiology.


Related Web Sites

Comets R Us
In the Beginning there was Dust
Daughters of Deep Impact
Seeing Comets Clearly
Comet Cookbook
Cardiff Centre for Astrobiology


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