From Nature, 390, 454 (1997)

No 'nanofossils' in martian meteorite

The 'martian fossils' found in the meteorite ALH84001 appear to be too small to be fossilized bacteria. Can these structures be explained in less spectacular terms than as the remains of unknown past life forms? Yes, according to the authors who suggest that artefacts of electron microscopy can combine with inanimate magnetite whiskers to produce a 'nanofossil' effect. The authors of the original paper, however, disagree.

J P Bradley, R P Harvey & H Y McSween Jr; Reply - D S McKay, E Gibson Jr, K Thomas-Keprta & H Vali