is the designation of a meteorite
fragmented, generally regarded as originating on Mars
. It was discovered in December 1984
by a meteorite-search expedition of the ANSMET[?]
program, as one of 7000 others. 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 3.7 billion years ago. Roughly 13000 years ago, ALH84001 impacted on earth.
ALH84001 became known because of certain microscopic
structures that were for some time considered the remains of bacteria
-like lifeforms. This would have been the first proof of extraterrestrial life and, eventually, panspermia
theory. Today, the actual origin of the tube-like structures is still subject of disputes.
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