CARDIFF, Wales, Aug. 15 (UPI) -- Welsh scientists said recent probes inside comets suggest it is likely life began in space.
Professor Chandra Wickramasinghe and colleagues at Cardiff University's Center 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.
Now the team reports findings from space probes sent to investigate passing comets reveal how the first organisms could have formed.
The 2005 Deep Impact mission to Comet Tempel 1 discovered a mixture of organic and clay particles in the comet. One theory for the origins of life proposes 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, which are considered potential building blocks for life.
The researchers calculate the odds of life starting on Earth rather than inside a comet at one trillion trillion, or 10 to the power of 24, to one against.
The study, which also involved Professor Bill Napier and Janaki Wickramasinghe, is to be published by the International Journal of Astrobiology.