Origem da vida é mais fácil do que se imaginava: basta uma colisão de cometa contra a Terra no ângulo certo

segunda-feira, março 29, 2010

Published online 26 March 2010 | Nature | doi:10.1038/news.2010.152

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Comet crash creates potential for life

Shock waves could force amino-acid forming chemistry.

Katharine Sanderson

Striking a glancing blow to a planet could create the perfect conditions in a comet's icy core to create amino acids — molecules that are vital to forming life on Earth.

This shock-compression theory for making amino acids has been developed by Nir Goldman and his colleagues at the Lawrence Livermore National Laboratory in Livermore, California. Goldman presented their results on 24 March at the American Chemical Society meeting in San Francisco, California.


Hitting a planet at the right angle could trigger the formation of molecules necessary for life on Earth.
NASA

The researchers wanted to find out what chemical events might occur in an ice grain trapped inside a comet glancing off a planet. They used around one million computer hours on the powerful Atlas computer cluster at Lawrence Livermore to simulate the possible chemical processes occurring in a single ice grain during such an impact. In particular, they were looking for amino acids — markers of potential life.

Previous theories for how amino acids on Earth might have come into being include lightning strikes on a primordial soup of simple molecules or the ultraviolet irradiation of interstellar dust grains, but none of the theories proposed so far is definitive.

Goldman's simulations included 210 molecules: a mixture of water, methanol, ammonia, carbon dioxide and carbon monoxide. This mix is commonly used by scientists to represent ice in comets.
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