Fish-eye picture of the 45-m-diameter Kamil Crater, southern Egypt. Full story.
Credit: Museo Nazionale dell'Antartide Università di Siena
What may be the best-preserved small impact crater ever seen on Earth has been discovered in the remote Egyptian desert, scientists announced Thursday.
The crater, called Kamil, is positively pristine when compared to most holes in the Earth gouged by impacting meteorites. Where many craters on our planet are partially eroded, this one retains much of its structure, down to even the rays of ejected material that were shot from the center when the space rock hit. [Photo of the new impact crater]
"This crater is really a kind of beauty because it's so well-preserved that it will tell us a lot about small-scale meteorite impacts on the Earth's crust," said study leader Luigi Folco, meteorite curator at the Museo Nazionale dell'Antartide in Siena, Italy. "It's so nice. It's so neat. There is something extraordinary about it."
Generally, craters this immaculate are found only on the moon or Mars, where there are fewer environmental and atmospheric processes to destroy them, he said.
Holes in the Earth
The Kamil crater ? 148 feet (45 meters) wide ? was first spotted in Google Earth satellite photographs by Vincenzo de Michele, a former curator of the Civico Museo di Storia Naturale in Milan, Italy.
Based on the size and characteristics of the bowl-shaped crater, the researchers think it was caused by the impact of an iron meteorite about 4.3 feet (1.3 meters) in diameter traveling at 7,920 mph (11,732 kph).
To verify the discovery, a team of geophysicists, including Foldo, descended on the site in southern Egypt's Sahara desert in February 2010.
"The first real impression when we were in the field ? we could see with our eyes that it was really well preserved and a potential source of detailed information about this kind of event," Folco told SPACE.com.
Folco is lead author on a paper published in the July 23 issue of the journal Science announcing the find.
The scientists can't be sure how long ago the Kamil meteorite crash occurred, but they estimate it was roughly a few thousand years ago ? in other words, relatively recent, in geological terms.
There are only about 175 confirmed Earth impact craters, even though the planet is barraged by space rocks slamming into it relatively often. Yet most craters are worn away easily on the ever-changing surface of Earth.
"This is important because small impacts are rather frequent on Earth ? on the order of one event every 10 to 100 years," Folco said. "So studying this crater is a good opportunity for scientists to get to a correct assessment of the hazard small impacts pose to the Earth and to devise mitigation strategies."
Objects about the size of washing machines typically fall into Earth's atmosphere every month, but most burn up before they can reach the ground. Many of the resulting fireballs are not seen because they occur over remote areas or over the ocean. The Earth is more than two-thirds ocean.
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