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Amino acids in space
10 January 2007
Complex biomolecules could be produced by low-energy electrons on icy dust particles in space.
In an effort to understand how amino acids might form under irradiation in space, scientists have mimicked reactions that might play a role. They looked at the reaction of a mixture of ammonia and acetic acid on a diamond film when it is irradiated at 25 Kelvin with low-energy electrons.
Their results show that glycine, the simplest amino acid, was formed. This, say the researchers, demonstrates that low-energy electrons, which are abundant in interstellar ice systems, can initiate chemical modifications of complex ices at very low temperatures.
Low-energy electrons, which are abundant in space, can be used to make the amino acid glycine from a mixture of ammonia and acetic acid
Anne Lafosse at Paris-Sud University, France, and colleagues used vibrational high resolution electron energy loss spectroscopy to detect the amino acid.
'It is believed that the principal source of extraterrestrial organic matter, including the building blocks of life on Earth, is the product of thermal and radiation processing of molecules accreted on dust grains in the interstellar medium,' explained Lafosse. These results, she asserts, suggest that complex biomolecules can be produced by low-energy electrons acting on molecules in icy dust particles in space.
'The ultimate challenge,' said Lafosse, 'is to check whether such reactions could account for a significant budget of biochemicals delivered ready-made to the early Earth.'
Reactivity induced at 25 K by low-energy electron irradiation of condensed NH3-CH3COOD (1:1) mixture
A Lafosse, M Bertin, A Domaracka, D Pliszka, E Illenberger and R Azria, Phys. Chem. Chem. Phys., 2007