How Life Originated In Space
Life has probably existed on earth for about 3.5 billion years and ever since people could wonder, they have tried to understand its origins. From the first glimmerings of life it is thought that organisms as complex as bacteria had emerged within 0.5-1 billion years. But, this to some seems a rather short timescale for such an important step and suggest that a germ of life may have reached Earth from space.
Natalia Gontareva and E.A. Kuzicheva of the Institute of Cytology, Russian Academy of Sciences, in St. Petersburg, have identified an abiotic process that results in complex organic compounds, the monomeric units of nucleic acids, on the surface of comets, asteroids, meteorites, and cosmic dust particles. They reckon the synthesis of these monomers in space and their subsequent ferrying to earth on a meteorite or in another impact may have seeded life on earth and so significantly reduced the time of the early evolutionary steps.
Organic molecules, such as amino acids, organic acids, and sugars have been observed in material from extraterrestrial sources in the solar system. But, to confirm the possibility of nucleic acid bases also being synthesised under these conditions,the researchers have replicated the synthesis of 5'-adenosine monophosphate (5'-AMP, the predominant reaction product) under interplanetary conditions. The reaction must proceed under solvent-free conditions and incident ultraviolet radiation in a vacuum.
After 7-9 hours of reaction time the team could detect 5'-AMP. The chemical evolution of life may have started in space as well, they suggest. "There are two ways for life to emerge - terrestrial and extraterrestrial - both are possible. We are not neglecting the endogenous origin of life but suggest extraterrestrial delivery of organics could accelerate all the processes on Earth and thus reduce the early evolution period," explains Gontareva. "It is presumed that these space-made organic molecules could be safely transported to Earth's vicinity by being associated with mineral grains [which would protect them from UV degradation]," say the researchers. Their experiments utilized moon dust as a protector and successfully shielded the monomeric products from decomposition by UV.
Gontareva told Reactive Reports that the team has obtained more results concerning abiotic synthesis of polypeptides and nucleotides in the presence of meteorite dust; these are the same kind of experiments but using different extraterrestrial material. So, it seems, the Earth's primordial soup was primed with the monomers for making the polymeric components of primitive life.
More information on astrobiology investigations by Kuzicheva and Gontareva on the Mir spacecraft can be found at http://biospace.nw.ru/astrobiology/thesis/kuzicheva.htm
