An asteroid about the size of the one that leveled the forest in Tunguska, Siberia, a century ago flew past Earth on Monday – well within the Moon’s orbit. The risk of a future impact with the object is not yet known.
The asteroid, dubbed 2008 DD45, whizzed just 72,000 kilometers above the Earth’s surface. That is less than a fifth of the distance to the Moon and just twice the distance to geosynchronous satellites. http://www.newscientist.com/article/dn16697-tunguskasized-space-rock-buzzes-earth.html?DCMP=OTC-rss&nsref=online-news