Just One Question

Why do scientists think the meteorite that sparked speculation about life on Mars came from the red planet?

The rock has an unusual mix of minerals: shergotite, nakhlite, and chassignite, or SNC—"snick" for short. Very different from the vast majority of stony meteorites that have fallen to earth, SNC meteorites are quite like what we believe to be the surface composition of Mars. Moreover, most snicks are about 1.3 billion years old, making them much younger than other types. Their youth implies an origin from a relatively geologically active parent body—such as a large planet. This particular meteorite, with its possible evidence of primitive life, is about 3.6 billion years old, making it the oldest known snick sample around. The greater age makes astrogeologists believe it was blasted from rocks well below the Martian surface, which is where the other, younger Mars meteorites originated. It may be only in these older, deeper rocks that one can find evidence for early life on Mars.

Fesen

associate professor of physics and astronomy