Meteor Crater

Meteor Crater, also known as Barringer Crater, is a massive impact crater located in the desert of northern Arizona. It sits between the cities of Flagstaff and Winslow. This site is famous because science institutes, such as the American Museum of Natural History, call it the best-preserved meteorite crater on Earth.

The crater has a unique, somewhat squared-off outline. Scientists believe this shape was caused by regional jointing, which are natural cracks in the layers of rock at the site. Today, the land remains privately owned by the Barringer family through the Barringer Crater Company.

The formation of the crater began about 50,000 years ago during the Pleistocene epoch. At that time, the climate on the Colorado Plateau was much cooler and damper than it is today. The area was an open grassland with woodlands, home to animals like mammoths and giant ground sloths. The event was caused by a nickel-iron meteorite that was approximately 50 meters across.

As the meteorite entered the atmosphere, about half of its bulk was lost to vaporization, which is when a solid turns into gas. The impact released an estimated 10 megatons of TNT energy. While early models suggested the object struck at speeds of 20 kilometers per second, more recent research suggests the impact was actually slower, at about 12.8 kilometers per second.

Since the impact, the crater has undergone some natural changes. The rim has lost some of its original height due to natural erosion. Inside the basin, there is a layer of rubble sitting above the crater bedrock. This floor contains roughly 30 meters of post-impact sedimentation. This sedimentation includes material from old lake sediments and alluvium, which is soil moved by water.

Despite these changes, the dry Arizona climate has helped preserve the crater's shape. Most other impact craters on Earth have been erased by geological processes like wind and water erosion.

For many years, the true cause of the crater was a subject of scientific debate. In 1891, the mineralogist Albert E. Foote presented the first scientific paper about the meteorites in Northern Arizona. He had analyzed an iron rock and realized it was a meteorite. He led an expedition that collected samples ranging from small fragments to pieces over 100 kilograms. He even found microscopic diamonds within the meteorites.

However, other scientists disagreed. In November 1891, Grove Karl Gilbert, the chief geologist for the U.S. Geological Survey, investigated the site. He concluded that the crater was formed by a volcanic steam explosion rather than an impact. Gilbert believed the meteorite fragments found nearby were just a coincidence.

Daniel M. Barringer was one of the first people to argue strongly for the impact theory. He believed a large iron meteorite had created the hole. Barringer was so convinced that he spent 27 years and much of his fortune trying to find a massive deposit of iron under the crater floor. He even drilled to a depth of 120 meters, but he never found a significant deposit. He did not realize that most of the meteorite had actually vaporized during the impact.

By 1928, he had spent roughly $500,000, which would be worth millions of dollars today. His efforts eventually helped shift scientific opinion toward the impact hypothesis.

In the 1930s and 1940s, Harvey H. Nininger helped bring widespread interest to the study of meteorites. He conducted research at the crater and discovered impactite, which are rocks changed by the impact. He also found iron-nickel spherules, which are tiny droplets created when the asteroid vaporized. Nininger's work helped the scientific community accept the impact theory. He also wanted the crater to become a national monument. This led to a disagreement with the Barringer family, who ended his exploration rights after he tried to have the crater nationalized.

Today, the site is a significant place for studying space history. The largest piece of the meteorite ever found is the Holsinger fragment. It is about 0.8 meters across and is displayed at the visitor center.

Fragments from the event are officially called Canyon Diablo meteorites. This name comes from the nearby Canyon Diablo, which is where the closest post office was located. In November 1967, the site was officially designated as a National Natural Landmark. The crater remains a vital link to understanding how celestial bodies interact with planets like Earth.