A meteorite from Mars that landed on Earth in 2011 contains a carbon compound that is biological in origin
NASA rover Curiosity is beavering away up on Mars, examining rocks, drilling holes, checking out the weather — but it’s not just up there to look at the planet’s hospitability for humans. It’s also looking for conditions favourable for life; not now, but in the past, when Mars may have been home to extraterrestrial microbes.
But maybe the answer is right here on Earth, after all — in the form of a meteorite.
Tissint landed in the desert of Guelmim-Es Semara, Morocco, on July 18, 2011. It was thrown from the surface of Mars by an asteroid collision some 700,000 years ago — and there is no other meteorite quite like it. The 7-11 kilogram grey rock — seared glassy black on the outside by the heat of entry, called a fusion crust — showed evidence of water. It was riddled with tiny fissures, into which water had deposited material.
This material, on analysis, turned out to be an organic carbon compound — one that was biological in origin. It is not the only meteorite in which organic carbon has been found, but the debate has always centered on whether the carbon was deposited before or after the meteorite in question landed on Earth — to wit, whether it is terrestrial or extraterrestrial in origin. . . .