Meteorite shower clue to planets’ birth

Scientists have collected hundreds of rare space rocks that crashed to earth on a day it rained stones from the sky. The celestial bombardment happened when an 80-ton, incoming asteroid exploded in the atmosphere.

Nearly 280 meteorites were found scattered across a large area of the Nubian Desert in Africa – and they are unlike any ever found before.

Scientists believe the 4.5 billion year-old stones will provide fascinating new evidence about how the solar system and planets formed.

The rocks are fragments of a cosmic missile that was the first ever detected on a direct collision course with Earth. It was spotted just a day before impact by a robotic telescope for the Catalina Sky Survey in Arizona.

Fortunately, Armageddon was avoided because the asteroid was a small one, about the size of a bus, and hit a sparsely populated region of Sudan in October.

Scientists had thought the asteroid labelled 2008 TC3 – had disintegrated into dust in the blast, less than 25 miles above the Nubian Desert. The flash was snapped from space and seen by a KLM airline pilot 750 miles away. Its twisting trail was also photographed from the ground.

But Peter Jenniskens, a meteor astronomer with ET-hunters the SETI Institute, organised an expedition to the site with scientists from the University of Khartoum.

They collected the first ever meteorites found from such a high altitude explosion. And they are different to any known meteorites. Jenniskens, who reports on the find in the journal Nature this week, said: “This was an extraordinary opportunity, for the first time, to bring into the lab actual pieces of an asteroid we had seen in space.”

UK astronomers from Armagh and Belfast, using the giant William Herschel telescope on La Palma in the Canary Islands, got the only measure of the asteroid’s spectrum as it approached. It was found to be an F-class asteroid that may only have spent a few million years orbiting in the inner regions of the solar system.

“These observations were technically quite difficult since the object was moving fast across the sky,” said Dr Gavin Ramsay from Armagh Observatory.

Fellow researcher Rocco Mancinelli, of the SETI Institutes Carl Sagan Centre, said: 2008 TC3 could serve as a Rosetta Stone, providing us with essential clues to the processes that built Earth and its planetary siblings.

Picture: Peter Jenniskens with some of the meteorites in the desert. (Photo: NASA).

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