Most of the space boulder that smashed to Earth to create Meteor Crater in Arizona melted upon impact 50,000 years ago and sprayed molten material in every direction.
A study appearing Friday in the journal Science concludes that an iron meteor 100 feet in diameter and weighing about 60,000 tons sailed in from space at almost 45,000 m.p.h. and smashed into the desert floor near Winslow, Ariz.
The collision erupted with the force of a 20-megaton bomb and sprayed molten rock for miles around the crater, says Elisabetta Pierazzo, co-author of the study and a researcher at the University of Arizona Lunar and Planetary Laboratory.
Left behind was a bowl-shaped crater about 4,000 feet wide and 570 feet deep. It was the first crater on Earth to be identified, by earlier studies, as being caused by a meteoroid.
Pierazzo and her co-authors used a computer simulation developed at Sandia National Laboratories in New Mexico and chemical analysis of bits of the space boulder to determine that about 85 percent of the meteor melted upon contact. Only the back 15 percent of the 100-foot space rock did not melt, but, instead, broke into bits of that have been called Canyon Diablo meteorites.
The melted portion turned into grain-size particles called spheroids that were spread far and wide by the impact. Only a small bit of the spheroids and bits of unmelted meteor have been found.
Earlier estimates had put the impact speed of the meteor at about 33,000 miles per hour, but Pierazzo said that the new study confirms the faster 45,000 mile-per-hour speed.
Co-authors of the study included researchers from Rutgers University, the University of Rhode Island, the University of California, Berkeley, and the Australian National University in Canberra.