Wednesday, March 24, 2021

The Meteor Crater

Meteor Crater is probably the most famous impact crater on the Earth's surface. Located in Arizona, it has a diameter of 1200 meters and is 170 meters deep.

The crater has been known for several centuries, but until the early 1900s it was believed to be a geological structure of volcanic origin.

It was only in 1903 that mining engineer and businessman Daniel Barringer hypothesized it had a meteoritic origin. Being convinced of this Barringer managed to obtain a mining concession with the aim of looking for the remains of the asteroid from which to extract minerals. Barringer's mining company failed to achieve its purpose, but it still exists today and still owns the crater.

Going back to 1903, Barringer's hypothesis remained as such for several years, until it was confirmed in the 1960s by Eugene Shoemaker, who was able to identify some minerals inside the crater whose presence could only be explained through a meteorite impact.

Since then, various geological studies have made it possible to determine the history of the crater with great accuracy.

Meteor Crater is currently believed to have formed about 49,000 years ago following the impact of an iron-nickel asteroid with a diameter of about 46 meters.

On the other hand, it was more complicated to establish the speed of impact. The most recent estimates suggest that the asteroid hit the surface at a speed of 12 km/s. It is believed that the impacting body began to vaporize into the atmosphere and that it completely disintegrated upon impact: this would explain why Barringer's company was never able to recover its remains. It was also possible to estimate the amount of energy released during the impact, which turned out to be more than 600 times that developed by the Hiroshima atomic bomb.

image Credit: Steve Jurvetson.

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