LIFE ON MARS?
Possible similarities between Earth and ancient Mars beg the question: if life emerged here, why not on Mars?
Maybe it did. A recently discovered meteorite that came from Mars may contain traces of life. This meteorite, designated ALH84001, is believed to have been blasted off Mars by a comet or asteroid impact, after which it wandered through space before crashing to Earth. ALH84001 contains gas bubbles whose chemistry matches the Martian atmosphere that was sampled by the Viking landers.
What excited scientists was the presence of curious structures, thought to be the fossilized traces of microscopic, bacteria-like organisms. Whether or not these features are actually Martian fossils will probably not be clear until more samples are collected directly from Mars. But even if the features in this particular meteorite fail the test, the question of ancient life on Mars remains a tantalizing possibility.