ALH84001 is a meteorite found in Antarctica in December 1984 by a team of US meteorite hunters from the ANSMET project, among 7000 others. Like other members of the group of SNC s, ALH 84001 is almost certainly from Mars, blasted off of the surface some 3.6 billion years ago in a meteorite impact.

On discovery, its weight was 1.93 kg. According to NASA, it was formed on Mars from molten lava about 4 billion years ago, then came to Earth as another meteorite impacted on Mars, throwing ALH84001 off Mars' surface as debris, about 15 million years ago. Roughly 13,000 years ago, ALH84001 impacted on Earth.

In 1996 ALH 84001 became newsworthy when it was announced that it was believed that the meteorite contained traces of life from Mars, as published in an article in Science by Dr. David McKay of NASA.

Certain microscopic structures that were for some time considered to be the remains of bacteria-like lifeforms. The structures found on ALH84001 are 20-100 nanometres in diameters, similar in size to the hypothetical nanobacteria, but smaller than any non-hypothetical earthly lifeform. If the structures are really fossilized lifeforms, they would be the first proof of extraterrestrial life and, potentially, the panspermia theory.

This caused a considerable stir at the time and opened up interest in Martian exploration. As of 2003 however, most experts agree that the microfossils are not indicative of life.

See also

• Martian meteorite

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External links

• http://www.jpl.nasa.gov/snc/alh.html
• http://www-curator.jsc.nasa.gov/curator/antmet/mmc/84001.pdf
• Mars Meteorite ALH 84001 – An Illustrated History