Biological Activity in the Early Solar System in Its Outer Regions (University College Cardiff Press, 1985)

Abstract

Chemoautotrophic microorganisms were able to replicate and evolve in the interiors of some10¹¹ cometary bodies that occupied the outer regions of the solar system some 4 billion years ago. The requirement of a liquid condition within comets was maintained for an initial epoch through the energy released in radioactive decays. When such energy sources eventually became exhausted inward freezing led to the production of multi-cracked, fragile cometary structures.