Asteroid Dust : “Meteorite’s Ancient Origins Confirmed”

Saturday, August 27th 2011. | Science News

Last year, a Japanese spacecraft brought asteroid dust back to Earth for the first time, and now researchers analysing the dust report that most meteorites on Earth originate from stony S-type asteroids like the one sampled, confirming what scientists have long theorized, but hadn’t been able to prove. Through actual, physical sampling of the dust particles, less than four thousandths of an inch in length, researchers were able to confirm that the dust is identical to material that makes up meteorites.

This and other findings are published in a set of six papers in the current issue of the journal Science. The asteroid dust was gathered by Hayabusa, a spacecraft launched by the Japan Aerospace Exploration Agency in 2003. It arrived on the surface of an Stype asteroid known as Itokawa more than two years later, and then re-entered the Earth’s atmosphere and landed in southern Australia previous summer.

Meteorites that hit the Earth are thought to be among the oldest objects in the solar system, and the research confirms that S-type asteroids are indeed ancient, said Tomoki Nakamura, a scientist at Tohoku University in Sendai, Japan, and an author on each of the studies. They are “primitive planetary bodies that record the history of the early solar system,” Nakamura said. He and his colleagues made other discoveries about the asteroid. They believe that the dust had been lying on the asteroid’s surface for about eight million years.

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