Asteroid's path predicted for the first time

Scientists for the first time predicted the arrival of an asteroid before it entered Earth's atmosphere.

The asteroid, 6 to 15 feet in diameter, entered the atmosphere over Sudan early Tuesday, providing a brilliant light show in East Africa as it burned up. Scientists said it posed no threat to people on the ground, though some tiny pieces of the object may have reached Earth's surface.

The important thing, scientists said, was not the discovery, but the prediction of its trajectory.

The object was first seen early Monday by the Catalina Sky Survey telescope near Tucson, Ariz. At the time, the object was outside the moon's orbit. Information from the observation was shipped to the Near-Earth Object Program Office at the Jet Propulsion Laboratory in La Canada Flintridge, Calif.

"We did an impact analysis and saw that it would indeed hit" the Earth, or at least its upper atmosphere, said Don Yeomans, director of the office charged with monitoring space rubble.

Space observers, including the Department of Defense, were alerted.