By Sid Perkins
Scientists have crunched the numbers for the September 2007 meteorite that landed in the Andes and suggest that the larger than normal impact crater resulted from the object’s unusually high speed.
Most stony objects that blaze through Earth’s atmosphere are blasted to bits by air resistance at high altitude (SN: 11/23/02, p. 323). Because the meteorite that struck eastern Peru on September 15 landed intact, its minerals must have been stronger than those typically found in similar extraterrestrial objects, says Peter Brown, an astronomer at the University of Western Ontario in London, Ontario. He and his colleagues report the first comprehensive analysis of the 2007 impact in an upcoming Journal of Geophysical Research–Planets.
Data gathered by infrasonic sensors — part of the worldwide system designed to detect atmospheric pressure waves from nuclear explosions — indicate that the object entered the atmosphere from the east-northeast at a speed of around 12 kilometers per second.