Images of the Earth's earliest fossils?

Abstract

Fossil remains of the most ancient, minute forms of life on Earth and other planets are hard to recognize. Schopf et al.¹ claim to have identified the biological remnant material known as kerogen in microscopic entities in rock by using Raman spectroscopic analysis. On the basis of a substantial body of published evidence, however, we contend that the Raman spectra of Schopf et al.¹ indicate that these are disordered carbonaceous materials of indeterminate origin. We maintain that Raman spectroscopy cannot be used to identify microfossils unambiguously, although it is a useful technique for pinpointing promising microscopic entities for further investigation.