MORE than a decade after the furore over a Martian meteorite that some claimed contained fossil microbes, a new analysis suggests the rock鈥檚 environment on Mars was conducive to life.
In 1996, some scientists argued that ALH 84001, a Martian rock found in Antarctica, contained complex carbon-based molecules and some microscopic markings shaped like bacteria. Sceptics said that the shapes were ambiguous and that the molecules could have been formed at temperatures of 650 掳C or so. Even the hardiest known microbes on Earth die above about 120 掳C.
But an analysis of the other mineral deposits in ALH 84001 鈥� such as those containing calcium and iron 鈥� by Paul Niles of NASA鈥檚 Johnson Space Center in Houston, Texas, and his team suggests that water surrounded the rock and had been cool enough for life to thrive. 鈥淭hese minerals were formed in what is very likely to have been a habitable environment,鈥� says Niles.
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This keeps open the possibility that the meteorite does indeed contain fossils (Earth and Planetary Science Letters, ).