This just happened:
|Animation of the trajectory of asteroid 2005 YU55 compared to the orbits of the Earth and the Moon on 8–9 November 2011.|
2005 YU55 is a potentially hazardous asteroid that is 400 meters in diameter. It was discovered on 28 December 2005 by Robert S. McMillan at Steward Observatory, Kitt Peak. On November 8 2011 it passed 0.85 lunar distances (about 324,600 kilometers, or 201,700 miles) from the Earth. This is the closest known approach by an asteroid with an absolute magnitude this bright since 2010 XC15 (H = 21.4) approached within 0.5 lunar distances in 1976.