SNC achondrite. Stony meteorite. Al Buhayrah, Egypt. 1911.
Of the circa 40,000 meteorites currently known, fewer than a hundred come from Mars. Nakhla is one of these extremely rare Martian meteorites.
DOG STRUCK DEAD?
Many people witnessed the fall on 28 June 1911 of some 40 fragments of the Nakhla meteorite, 40 kilometers east of Alexandria, penetrating up to one meter into the ground – the total weight was around 10 kilograms, although most fragments were significantly less than one or two kilograms in weight. One of these fragments allegedly hit and killed a dog, although there is no proof of this story.
The NHM acquired two fragments from this meteorite shower immediately after its fall, together weighing about 0.5 kg – only three museums in the world have more mass of Nakhla.
Most stony meteorites are fragments of asteroids, which date back to the origin of our Solar System, and are around 4.5 billion years old. Only a few have a different origin. The most famous of these exceptions are Shergotty, Nakhla, and Chassigny. These gave their names to the “SNC meteorites”. The NHM has fragments of all three of these meteorites.
The origin of the SNC meteorites was finally resolved in the 1980s. Three observations together put scientists on the right track. Many SNC meteorites are less than 1.3 billion years old. This means they must originate from a planet that was “recently” geologically active. The composition of the SNC meteorites is also very similar to that of the surface of Mars, as revealed by spacecraft. In addition, many of the SNC meteorites have inclusions containing gas with the same chemical and isotopic composition as the Martian atmosphere.