Science News | Earth | 22 July 2010
Pristine Impact Crater Discovered in Egypt DesertEgyptian impact crater first spotted on Google EarthCredit: Museo Nazionale dell'Antartide Università di Siena
Researchers poring over Google Earth images have discovered one of Earth’s freshest impact craters — a 45-meter-wide pock in southwestern Egypt that probably was excavated by a fast-moving iron meteorite no more than a few thousand years ago.
Although the crater was first noticed in autumn 2008, researchers have since spotted the blemish on satellite images taken as far back as 1972, says Luigi Folco, a cosmochemist at the University of Siena in Italy. He and his colleagues report their find online July 22 in Science.
The rim of the Egyptian crater stands about 3 meters above the surrounding plain, which is partially covered with distinct swaths of light-colored material blasted from the crater by the impact. These rays, which emanate from the impact site like spokes from the hub of a wheel, are what drew researchers’ attention to the crater, says Folco. While such “rayed craters” are common on the moon and other airless bodies of the solar system, they are exceedingly rare on Earth because erosion and other geological processes quickly erase such evidence.
During expeditions to the site early in 2009 and again this year, scientists found more than 5,000 iron meteorites that together weigh more than 1.7 tons. The team estimates that the original lump of iron weighed between 5 and 10 metric tons when it slammed into the ground at a speed of around 3.5 kilometers per second, with most of the material vaporizing during the collision.
Analyses of soil samples from the site and of sand fused into glass by the impact’s intense heat and pressure may help the team estimate when the event occurred. Preliminary analyses suggest that it happened sometime during the last 10,000 years, probably no more than 5,000 years ago, Folco says.
The Kamil Crater in Egypt - L Folco et al
[list]Science (online 22 Jul 2010) DOI: 10.1126/science.1190990[/list]
Space.com | Science | 22 July 2010
"Fresh" Crater Found in Egypt; Changes Impact Risk?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.
"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.
National Geographic News | 22 July 2010
A small impact crater discovered in the Egyptian desert could change estimates for impact hazards to our planet, according to a new study.
One of the best preserved craters yet found on Earth, the Kamil crater was initially discovered in February during a survey of satellite images on Google Earth. Researchers think the crater formed within the past couple thousand years.
The Italian-Egyptian team that found the crater in pictures recently visited and studied the 147-foot-wide (45-meter-wide), 52-foot-deep (16-meter-deep) hole. The team also collected thousands of pieces of the space rock that littered the surrounding desert.
Based on their calculations, the team thinks that a 4.2-foot-wide (1.3-meter-wide) solid iron meteor weighing 2,267 to 4,535 pounds (5,000 to 10,000 kilograms) smashed into the desert—nearly intact—at speeds exceeding 2.1 miles (3.5 kilometers) a second.
Went right past me. How about (1,000 to 2,000 kilograms)?
