Beneath the distance of our geosynchronous satellites? Close but no doom.
Astronomers are gearing up to observe asteroid Apophis, which will come to within 0.1 A.U. (14,450,000 kilometers; 8,980,000 miles) of Earth on Wednesday, January 9, 2013, and which will come close again in subsequent years with anextremely remote possibility of striking Earth in 2036. In late 2012 and early 2013, Apophis has been observable using both optical and radar equipment. The data collected around now are expected to make possible a significant improvement in our understanding of the orbit of Apophis and remove any possibility for an Earth impact on April 13, 2036. However, as David Helfand of Columbia said when EarthSky interviewed him in 2010 on killer asteroids, the risk from Apophis is already essentially zero.