Percolation clusters of organics in interstellar ice grains as the incubators of life.
Biomolecules can be synthesized in interstellar ice grains subject to UV radiation. I show that the large dose of UV radiation per molecule over sufficiently long time scales leads to the creation of large percolation clusters of organic molecules. Such clusters will have large network of pores traversing their entire lengths, which eventually collapse into small local networks. Some of these clusters would have ended up in proto-planets where large, loosely bound aggregates of clusters (superclusters) could have formed. The interior regions of such superclusters provided for micro-environments that are filtered versions of the outside environment. Biochemical systems present inside such micro-environments would be subject to cold-warm cycles. Models of abiogenesis where such cold-warm cycles play an important role, can then also be considered inside such superclusters.
The filtered nature of the micro-environment makes such models more likely to work. As the supercluster gradually breaks up, the biochemical system gradually becomes subject to a less filtered environment, allowing it to get adapted to the more complex outside environment. A particular system originating from a particular location on some supercluster would have been the first to get adapted to the raw outside environment and survive there, thereby becoming the first microbe. A collision of a microbe-containing proto-planet with the Moon could have led to fragments veering off back into space, microbes in small fragments would have been able to survive a subsequent impact with the Earth.
Publisher URL: http://arxiv.org/abs/1711.01945
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