Tracing life back into space: a difficult task

摘要

Precambrian microfossils were used for a comparison in the study of the microstructures in carbonaceous meteorites. As a result, three morphological categories could be distinguished in the meteorite materials. Category 1- morphologies are such simple spheres and filaments that we can hardly be confident about biological assignments. Category 2-morphologies closely resemble structures known from laboratory experiments and thus should continue to be treated as non-biogenous. Morphologies of the third category are quite comparable to terrestrial microfossils in their preserved features and thus might be biogenous. Our observations suggest that carbonaceous meteorites are heterogenous in composition and contain particles from different extraterrestrial sources and of different ages.