It was only discovered four days before its nearest approach.
Phew! Asteroid's passing was a cosmic near-miss
PASADENA, Calif. – An asteroid about the size of one that leveled more than 800 square miles of forest in Siberia a century ago just buzzed the Earth. The asteroid named 2009 DD45 was about 48,800 miles from Earth when it zipped past early Monday, NASA's Jet Propulsion Laboratory reported.
That is 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.