Structure in the meteorite ALH 84001.The tiny piece of
carbon found in meteorites from Mars were formed by the cooling of volcanic
emission, were not left there by ancient space germs. This is good news and bad
news for astrobiologists.
The discovery in 1996
of carbonate structures in the meteorite ALH 84001, which traveled from Mars to
Earth 13,000 years ago, was hailed at the time as evidence that
extraterrestrial microbes have ever lived on the Red Planet. However, further
studies of both the carbonate structures as tiny bits of macromolecular carbon
(MMC) in the meteorite cast doubt on those claims.
