Arizona
The meteorite that blasted Meteor Crater was about the size of three school buses lined up end to end. However, the hole it created is nearly 4000 feet wide and more than 500 feet deep.
Each year, Earth is struck by an average of five to ten meteorites that make it all the way through our protective atmosphere. Most of these events are small, causing no damage or injuries. But a few times in our planet’s 4.5-billion-year history, meteorite impacts have been catastrophic, including the impact that likely played a role in the global extinction of dinosaurs.
Only a small number of meteorite impact craters are visible on Earth’s surface today, because of the erasing power of erosional forces over millions of years. Meteor Crater is young enough, however, that it appears almost the same today as it would have looked when it was blasted into the planet 50,000 years ago. From the air, it is easy to spot: a round hole in the ground surrounded by a raised rim of rock, just south of Interstate 40 in east central Arizona.
For a long time, scientists weren’t sure whether Meteor Crater was indeed a crater made by a meteorite, or a volcanic crater linked to the San Francisco Volcanic Field just forty miles to the west. It wasn’t until the 1960s that the crater was conclusively confirmed as being caused by meteorite impact—the planet’s first scientifically recognized meteorite impact crater. The breakthrough came with the discovery at the site of the minerals coesite and stishovite, two rare forms of silica that can be formed only by a large impact or nuclear explosion.
Today Meteor Crater is 3900 feet in diameter, 560 feet deep, and surrounded by a rim of rock that rises 150 feet above the landscape. In the past 50,000 years, the crater rim is thought to have lost about fifty feet from its original height, while the bottom of the crater has been filled in with around a hundred feet of sediments shed from the unstable crater walls. Otherwise, its size and shape are very much the same as just after the dust settled.
One of the longstanding mysteries of Meteor Crater is the seemingly missing meteorite. The object that created the crater was probably an iron-nickel meteorite about 160 feet across that generated more than ten megatons of explosive energy upon impact—over three times the combined energy released by the Hiroshima and Nagasaki atomic bombs in World War II. Most of the meteorite was likely vaporized, leaving little evidence behind in the crater.
Because the collision that created it was a relatively recent 50,000 years ago, Meteor Crater still looks very much like it did just after impact. Most of the meteorite was destroyed on impact; only small pieces of the estimated 160-foot-long impactor have been recovered from the crater.
You might fly over Meteor Crater en route to Flagstaff, Arizona, which lies just forty miles to the west.
