Aerial view of Barringer Crater, in northeastern Arizona, USA. It is also known as Meteor Crater. The crater is some 1200 metres in diameter and about 170 metres deep. It is thought to have been formed around 50, 000 years ago by the impact of a nickel-iron asteroid some 50 metres in diameter. The crater is named for the geologist Daniel Barringer (1860-1929), who hypothesised that it had been formed by a meteorite impact after drilling in the crater while looking (unsuccessfully) for iron. Despite the large size of the impacting body, relatively little of it has been found. The fragments recovered, known as the Canyon Diablo meteorites, amount to around thirty tonnes, an estimated 0.1% of the original mass. Most is thought to have vaporised on impact.