Other sources of organic molecules

We also know that a considerable enrichment of prebiotic moieties may have come from submarine vents and other hydrothermal sources (see, for example, Miller and Bada, 1988 Holm and Andersson, 1998 Stetter, 1998). Let s start with the 1979 discovery of deep-sea vents with black smokers, which are associated with an extraordinary abundance of the most phylogenetically primitive organisms on Earth. This ecosystem is sulphur based, and is distinct from the more familiar, photosynthetically-based ecosystem that dominates Earth s surface. Corliss et al. (1981) were struck by the richness of the vent biota, based on chemosynthesis, and proposed that these were the origin of life. 

University of California at San Diego, La Jolla, CA 92093-0212 Carbon and organic compounds in the universe 

Star formation and the formation of star systems with planets around them, constantly takes place in dense interstellar clouds. The material present in these clouds is incorporated into the objects that are formed during this process. Pristine or slightly altered organic matter from the cloud from which our solar-system was formed is therefore present in the most primitive objects in the solar system comets, asteroids, and outer solar-system satellites. Pieces of asteroids (and perhaps comets) can be investigated with regards to these components through the analyses of meteorites (and eventually in samples returned from these bodies by spacecraft) in laboratories on Earth. The infall of asteroid and comet material from space may have contributed to the inventory of organic compounds on primordial Earth. 

Indeed, the similarity of the molecules from space and the molecules of Earth is striking. For example, several aliphatic carboxylic acids up to Cg were detected, (Knenvolden et al, 1970), as well as alkyl phosphonates (Yuen and Knenvolden, 1973 Cooper et al, 1992 Pizzarello, 1994) and also heterocyclic pyrimidines (Hayatsu et al, 1975 Stocks and Schwarz, 1982). 

As rich as the Murchinson and other meteorites are, comets are perhaps the most generous source of organic compounds. They are particularly rich in HCN (Miller, 1998) which appears to be very common in space and it has for this reason been investigated by several authors (Ord, 1961 Ferris and coworkers, 1973,1974, and 1978 Matthews, 1975). 

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