ALH84001
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ALH84001 (representing 'Allen Hills 1984 #001') is a meteorite found in Allen Hills, Antarctica in December 1984 by a team of US meteorite hunters from the ANSMET project, among 7,000 others. Like other members of the group of SNCs, ALH84001 is almost certainly from Mars, shocked and broken by one or more meteorite impacts some 3.6 billion years ago, and blasted off of the surface of Mars in a separate impact about 15 million years ago.
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.
ALH84001_structures.jpg
Under the scanning electron microscope structures were revealed that for some time were 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, but of contamination by earthly biofilms.
See also
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 (http://calspace.ucsd.edu/marsnow/library/science/mars_meteorites1.html)de:ALH84001