By Xinhua,
Washington : An asteroid as big as a 10-storeyed building flew past Earth Tuesday, the US space website has said.
The space rock was perhaps a bit larger than one thought to have created a colossal explosion in the air above Siberia in 1908 that flattened 500,000 acres (2,000 square km) of forest.
Asteroid 2009 DD45 was closest to Earth Tuesday at about 8.40 a.m. It was some 72,000 km away, which is twice the height of a geostationary communications satellite.
Astronomers had known the asteroid was coming and said there was no risk of collision. Other asteroids have been known to pass by closer to our planet.
Asteroids as big as the 1908 Tunguska object that devastated the Siberian forest might strike Earth as often as once every two centuries, scientists speculate.
As space rocks enter Earth’s atmosphere, smaller ones can break apart or explode before hitting the surface.