It has been 100 years since Wells penned his well-known story of our first contact with extraterrestrial life. Now, at the end of the 20th century, some scientists are convinced that what was the domain of science fiction writers and prophets has become the stuff of science. Today, a meteorite from Mars is being keenly and closely scrutinized by earthly intelligences. We wouldn't, if it weren't for atmospheric data taken by the Viking spacecraft in the 1970s. The data make it possible to know that gases trapped inside these twelve rocks exactly match the martian atmosphere.
Meteorites are pieces of rock that enter Earth's atmosphere from space.
A lot of material entering in this way never even makes it to the ground. Instead, it burns up in the atmosphere. Scientists speculate that the Allan Hills meteorite was first chipped off of Mars about 15 million years ago by an asteroid or comet. The rock apparently tumbled through the solar system for a few million years, and finally reached Earth about 13,000 years ago. Romanek, who is now a geologist at the University of Georgia, was studying tiny pancake-shaped blobs of carbonate, a form of carbon, in ALH84001.