Tuesday, March 3, 2009

10-story-building-sized asteroid flies past Earth

WASHINGTON, March 3 (Xinhua) -- An asteroid of the size of a 10-story building flew past Earth on Tuesday about twice the distance as the highest Earth-orbiting satellites, the U.S. space website said on Tuesday.

The space rock was about 115 feet (35 meters) wide, 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 kilometers) of forest

Asteroid 2009 DD45 was closest to Earth on Tuesday at about 8:40 a.m. ET. It was some 44,740 miles (72,000 km) away. That's twice the height of a geo-stationary 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.

Terri, Events Coordinator
Phoenix Astronomical Society