This is an electron microscope image of a small chip from the ALH84001 meteorite. In the centre are several tiny structures that are said to be possible microscopic fossils of primitive, bacteria-like organisims that may have lived on Mars more than 3.6 billion years ago. The largest of these fossils are less than 1/100 th of the diameter of a human hair while most of them are ten times smaller. ( NASA)

Poly aromatic hydrocarbons (PHAs) were found concentrated in the vicinity of the carbonate. Which is consistent with terrestrial fossilization processes.