for National Geographic News
About 1,100 years ago a space rock the size of a big tree stump slammed into western Canada, carving an amphitheater-like crater into the ground and littering it with meteorites, a new study found.
The rock that made the newly identified crater might have created a sky show similar to the one that tore across northern Alberta's skies in the early evening hours of November 20 (watch video above).
But unlike the recent fireball—which broke apart as it streaked through Earth's atmosphere—the meteorite that carved the newly announced crater would have stayed solid until impact.
"You need to have that wallop," said study author Christopher Herd, an associate professor of earth and atmospheric sciences at the University of Alberta in Edmonton.
"You need to have that big mass still going fast in order to make the crater."
(Related: "Giant Meteor Fireball Explodes Over Northwest U.S." [February 21, 2008].)
Meteorites, objects from space that hit Earth, often come from asteroids.
Only about 175 impact craters are known worldwide, and when a space rock does slam into Earth with enough force to create a crater, the rock almost always evaporates on impact.
"Here we have a crater and we also have meteorites associated with it," Herd said. "There are only a dozen impact craters in the world that have that association."
Until recently, the Canadian crater was little more than a dip in a thicket of aspen trees known among local hunters as a good spot to bag a deer.
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