ARIZONA'S METEOR CRATER

Some 50,000 years ago, an asteroid sped through space at 30,000 miles per hour, headed straight for planet Earth.

- STEVE VOYNICK

Measuring about 150 feet in diameter and weighing 300,000 tons, it entered the Earth’s atmosphere at an altitude of 60 miles where the intense heat of atmospheric friction and compression caused it to glow. As its surface heated to 5000°F. (twice the melting point of iron), it began to melt, vaporize and fragment. Seconds later the remnants of the asteroid, preceded by a monumental atmospheric shock wave, slammed into Earth.

THE CRATER

At the time, no humans were around to witness the impact. But today a quarter-million people each year visit the Arizona Meteor Crater, which is located in northern Arizona 35 miles east of Flagstaff and just south of the “Meteor Crater” exit on Interstate 40.

Seen from a distance, the crater rim appears as a barely noticeable low ridge. But from atop the rim, the view into and across the crater dramatically conveys the cataclysmic nature of the event that created it—a meteoric impact that released the energy of a 20-megaton hydrogen bomb.

This impact instantaneously ejected some 175 million tons of limestone and sandstone, leaving a crater three-quarters of a mile in diameter, a rim rising 200 feet above the surrounding plain, and a crater floor extending 700 feet below the plain. Erosion has since reduced the rim’s height by about 60 feet, while sedimentation has filled in 100 feet of the crater floor.

A WOULD-BE IRON MINE