Posted: Mon, Aug 5, 2002, 8:38 AM ET (1238 GMT)
A team of scientists has published evidence that one quarter of the magnetite found in Martian meteorite ALH84001 could only have been created organically, the latest claim in the debate over whether the meteorite contains evidence of past Martian life. The study, led by NASA JSC scientist Kathie Thomas-Keprta and published in the journal Applied and Environmental Microbiology, found that 25 percent of the magnetite found in the meteorite had "remarkable physical and chemical similarities" to magnetite created by bacteria on Earth. A comprehensive study confirmed that the magnetite matched a Magnetite Assay for Biogenicity (MAB) used to determine if terrestrial magnetite is formed by bacteria; no magnetite crystals formed inorganically have met the MAB criteria. The magnetite crystals were one of the lines of evidence put forward in the original announcement, almost exactly six years ago, that ALH84001 contains evidence of past Martian life. Other researchers have argued since then that the magnetite was most likely formed by inorganic processes.

Related Links:

•  NASA press release