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Article: Celestial mechanics.(asteroid observations)(Brief Article)
- Article from:
- The Economist (US)
- Article date:
- March 6, 1999
CopyrightCOPYRIGHT 1999 Economist Newspaper Ltd. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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A rock in a hard place
ON FEBRUARY 23rd an asteroid called 1999BJ8 sailed past the Earth at a distance of 5m kilometres (3m miles)-a pretty close shave by astronomical standards. This is just one of several hundred rocks, varying in size from a few metres to a few kilometres across, whose orbits around the sun cross the Earth's. A few dozen are potentially extremely hazardous, because they could one day do to humanity what one of their number did to the dinosaurs 65m years ago. So understanding their behaviour is important. But astronomers have been unable to figure out how they get from the main asteroid belt between Mars and Jupiter to the vicinity of the ...