Comet impact on Earth are synonymous with great extinctions, but now research presented at the Goldschmidt geochemistry conference in Prague shows that early comet impact would have become a driving force to cause substantial synthesis of peptides -- the first building blocks of life. This may have implications for the genesis of life on other worlds.
Dr Haruna Sugahara, from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) in Yokahama, and Dr Koichi Mimura, from Nagoya University performed a series of experiments to mimic the conditions of comet impacts on the Early Earth at the time when life first appeared, around 4 billion years ago.
They took frozen mixtures of amino acid, water ice and silicate (forsterite) at cryogenic condition (77 K), and used a propellant gun to simulate the shock of a comet impact. After analyzing the post-impact mixture with gas chromatography, they found that some of the amino acids had joined into short peptides of up to 3 units long (tripeptides).
Based on the experimental data, the researchers were able to estimate that the amount of peptides produced would be around the same as had been thought to be produced by normal terrestrial processes (such as lighting storms or hydration and dehydration cycles).
According to Haruna Sugahara: "Our experiment showed that the cold conditions of comets at the time of the impacts were key to this synthesis, as the type of peptide formed this way are more likely to evolve to longer peptides.
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