The traditional thinking is that life on Earth began… on Earth. At some point in our distant past, some mixture of amino acids made the jump from a pool of organic molecules to something more lifelike. But maybe the source of life on Earth came from space, hitching a ride aboard balls of ice and dust: comets.
This is the controversial theory proposed by Chandra Wickramasinghe, an astrobiologist at Cardiff University in the United Kingdom. Wickramasinghe is one of the long time proponents for the theory of panspermia; that life on Earth originated from space or another planet.
Wickramasinghe and his team are claiming that new evidence gathered by space probes reveals how these first organisms could have gotten started.
When NASA’s Deep Impact spacecraft ended its life in 2005, crashing into Comet Tempel 1, it discovered a mixture of organic and clay particles inside the comet. One theory about the origins of life is that clay particles act as a catalyst, allowing simple organic molecules to get arranged into more and more complex structures. The 2004 Stardust mission found a range of complex hydrocarbon molecules when it collected particles from Comet Wild 2.
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The Cardiff team think that radioactive elements inside comets could make pockets warm and toasty enough to keep water in its liquid form for millions of years. These iceballs could serve as the perfect incubators for early life. And when one finally crashes into a planet, it delivers this life to its new home.
There are so many comets out there, with potentially so many liquid pockets inside, that Wickramasinghe and team calculated that the likelihood is far greater that life got started in comets, and not here on Earth.
With any controversial theory, there are many scientists who think this is just too speculative. Without actual evidence for one of these oases inside a comet, it’s just an interesting idea. Perhaps ESA’s Rosetta mission, currently on its way to Comet 67P/Churyumov-Gerasimenko, and equipped with a lander will be just to tool to gather this kind of evidence.
Original Source: Cardiff News Release