From the plains beside it, the rim of Meteor Crater looks like a low hill, giving no hint of the immense hollow it surrounds. Blasted out when a giant meteorite struck the ground here around 50, 000 years ago, the crater is about 3/4 mile (1.2km) across and 600ft (180m) deep, with a rim rising 150ft (45m) above the plain. Its floor is so like the moon’s terrain that Apollo astronauts trained there, and it was a testing ground for lunar vehicles.
Scientists estimate the meteorite’s speed as 45,000mph (72, 000km/h), and that on the impact it exploded with a force a thousand times greater than the nuclear bomb dropped on Hiroshima in 1945. It sent 5 or 6 million tons of rock and earth hurtling heavenwards and blocking out the sunlight. After the impact, the meteorite – a mass of nickel-iron reckoned to be some 130ft (40m) across and more than 300,000 tons in weight – disintegrated and melted. Remnants have been found within a 6-mile (10km) radius.
The crater was once thought to be volcanic, but a Philadelphian mining engineer named Daniel Barringer was one of the first to recognise it as a meteorite crater. In the belief that it was rich in nickel and iron, he staked a claim there in 1902 and spent a fortune trying unsuccessfully to mine it. Today the crater is also known as the Barringer Crater and is still owned by this family.
On average, large meteorites fall to Earth about once every 1300 years. The world’s largest intact meteorite, which probably also fell in prehistoric times, weighs 60 tons and lies near the town of Grootfontein in Namibia. The second largest, 30 tons, fell in west Greenland.