PASADENA, California - An asteroid about the size of one that leveled more than 2000 square km of forest in Siberia a century ago just buzzed the Earth.
The asteroid named 2009 DD45 was about 78,000km from Earth when it zipped past early Monday, Nasa's Jet Propulsion Laboratory reported.
Thatis just twice as high as the orbits of some telecommunications satellites and about a fifth of the distance to the Moon.
"This was pretty darn close," astronomer Timothy Spahr of the Harvard-Smithsonian Center for Astrophysics said Wednesday.
But not as close as the tiny meteoroid 2004 FU162, which came within 6400km in 2004.
The space rock measured between 21m and 47m in diameter. The Planetary Society said that made it about the same size as the asteroid that exploded over Siberia in 1908.
Scientists at the Siding Spring Observatory in Australia spotted 2009 DD45 and began tracking it in late February when it was about 1.6 million km away.
Spahr said he knew within an hour of that discovery that it would pose no threat to Earth.
Of the known space rocks, the next time an object will get closer to Earth will be in 2029 when a 270m asteroid called 99942 Apophis comes within 32,000km, said Donald Yeomans of Nasa's Near-Earth Object Program at the Jet Propulsion Laboratory in Pasadena.
Last year, the asteroid 2008 TC3 harmlessly burned up in Earth's atmosphere over Africa 19 hours after it was discovered. Astronomers gave a six-hour notice warning of that fiery plunge.
