Meteor Crater, Arizona This crater is 1.2 kilometers in diameter and was probably produced 15,000 to 40,000 years ago when a lump of iron 25 meters across impacted the Earth at a speed of 15 kilometers per second. The energy released was roughly equivalent to that of a 4-megaton nuclear explosion.
So-called Meteor Crater Arizona is only about 25,000 years old (see preceding page)...