for National Geographic News
For the first time, astronomers have been able to track down meteorites from an asteroid spotted before it broke up in Earth's atmosphere—and the space rocks are among the rarest known.
Automated telescopes at the Catalina Sky Survey in Arizona first sighted the truck-size asteroid 2008 TC3 barreling toward Earth in early October 2008.
Astronomers around the world soon trained several telescopes on the asteroid, tracking it for about 20 hours until it disappeared into Earth's shadow just before impact.
The asteroid was predicted to slam into the skies over Sudan and get blown to dust 23 miles (37 kilometers) over Earth. Meteor astronomer Peter Jenniskens decided to find out for sure.
"Meteorites have never been collected from something [that disintegrated] that high up in the atmosphere," said Jenniskens of the SETI (Search for Extraterrestrial Intelligence) Institute. "We didnt know whether we were going to find something."
On a long shot, Jenniskens and astronomer Muawia Shaddad of Sudan's University of Khartoum took students on a meteorite hunt.
The group struck gold, recovering dozens of fist-size or smaller black rocks made of "a material so fragile it was not previously represented in meteorite collections," Jenniskens said.
The unusual finds come from a rare type of asteroid and may offer new clues to the origins of the solar system.
"For the first time, we have a complete evidence chain," Michael Zolensky, cosmic mineralogist at NASA's Johnson Space Center in Houston, said during a press conference.
"This meteorite is the key to a much greater understanding of asteroids."
As predicted, 2008 TC3 had lighted up the sky over northern Sudan on October 6 at 5:45 a.m. local time, during the predawn hour of Arabic prayer.
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