New scientific evidence reveals that primitive life in the form of bacteria could have existed on Mars. Now, a team of scientists reports it has isolated crystals of magnetite, an iron oxide, from the meteorite and examined the crystals with electron microscopy. Among the crystals are some ranging in size from 10 to 200 nanometers across that have an unusual shape. The scientists determined that these magnetite crystals from the meteorite resemble magnetite crystals produced on Earth by biological processes. There is currently no known method of synthesizing these types of particles, and therefore, they may prove to be an excellent biomarker.
Magnetite is produced both biologically and inorganically on Earth.
Magnetotactic bacteria, which are common in aquatic environments, produce the crystals within their cells. The cells behave like miniature compass needles, using the crystals and the Earth's magnetic field to find conditions that promote their growth and survival in water and sediment. The magnetite crystals produced by magnetotactic bacteria are chemically pure and distinct in size and shape from crystals of nonbiological origin. The crystals from the Mars sample share the same characteristics of size, shape and chemical composition as those produced by the bacteria. The results will be published in the December issue of Geochimica et Cosmochimica Acta, the journal of the international Geochemical Society and Meteoritical Society.