Landsat spacecraft made orbital imagery of Earth readily accessible to the public in the 1970s, and ever since then space-age prospectors have pored over satellite photos in the hope of identifying new impact craters on our planet's surface. Usually these "discoveries" prove to be false alarms — Mother Nature has lots of ways of making circular holes in the ground.But the search goes on, and in February 2009 Vincenzo De Michele (Istituto Gemmologico Italiano) hit paydirt, both figuratively and literally. He used Google Earth aerial-survey imagery to identify an astrobleme in southern Egypt's East Uweinat Desert, near the Sudan border. (For the curious, the exact coordinates are 22° 1′ 6″ north, 26° 5′ 16″ east.; click here for a Google's-eye view.)
The aerial photography and De Michele's search were part of a year-long cooperative science effort among Italian and Egyptian researchers. Last February a field expedition visited the site, where team members found not only a remarkably fresh impact crater but also a scene littered with tons of meteorites. Score!
Owing to erosion by wind, water, and geologic mayhem, it's a rare to find evidence of cosmic collision on our planet. Only about 175 confirmed craters are known, and most of them retain little of their original character. But the new Kamil crater is so fresh that bright-hued splashes of ejected debris still paint the desert surface. The researchers, led by Luigi Folco (Museo Nazionale dell'Antartide, Siena, Italy), are still analyzing the details they gathered on site; a quick status report appears in July 22nd's edition of Sciencexpress.
The Kamil crater has a classic bowl shape, with a blocky, upraised rim about 10 feet (3 m) high. It's about 50 feet deep, though a thick layer of sand blankets the interior floor. Folco and his team estimate that the cosmic cannonball was an iron mass about 5 feet (1.3 m) across, weighing roughly 10 tons, that struck the desert at 2.2 miles (3.5 km) per second.The original meteoroid might have been up to four times more massive and traveling five times faster before it crashed through the atmosphere. In any case, when that whittled-down chunk of iron hit, it exploded with the power of 13 tons of TNT, spraying thousands of pieces around the scene. Folco's team identified 5,178 meteoritic fragments totaling 1.7 tons — the biggest single specimen weighs 183 pounds (83 kg) — but undoubtedly far more await discovery.
Officially named Gebel Kamil, the meteorites have already made news among collectors. The shiny, metallic interiors don't show the regular pattern of interlocking crystals typical of many other iron meteorites, likely due to the high nickel content (20%).
Well-connected dealers are already offering Gebel Kamil slices for about $10 per gram — pricey for a common iron meteorite but perhaps understandable given the heady buzz surrounding this new find.
I'm tempted to grab one, but for now I'll just window-shop. All the Kamil Gebel pieces now on the market have been collected illegally, according to expedition member Giancarlo Negro. "In fact, after our February 2010 mission, all the area was declared off limits by military authorities," and since then no one has been given permission to collect meteorites there.
The research team's website showcases many photos from their desert conquest.