A newly found asteroid will pass just inside the orbit of the Moon, with its closest approach on March 4, 2013 at 07:35 UTC. Named 2013 EC, the asteroid is about the size of the space rock that exploded over Russia two and a half weeks ago, somewhere between 10-17 meters wide. The asteroid that sparked the Russian meteor is estimated to have been about 17 meters wide when it entered Earth’s atmosphere.
2013 EC was discovered by the Mt. Lemmon Observatory in Arizona on March 2. There is no chance this asteroid will hit Earth.
2013 EC will come within 396,000 kilometers from Earth, (246,000 miles, or around 1.0 lunar distances, 0.0026 AU.
The Moon’s distance from the Earth varies between 363,104 km (225,622 miles) at perigee (closest) and 406,696 km (252,088 miles) at apogee (most distant point).
Gianluca Masi from the Virtual Telescope Project had a live view of the asteroid when it was about twice the distance of the Moon, and a replay of that webcast is available below. (Views of the asteroid start at about 31:00 in the video.)
“That we are finding all these asteroids recently does not mean that we are being visited by more asteroids,” Masi said during the webcast, “just that our ability to detect them has gotten so much better. Our technology has improved a lot over the past decades.”
More info about 2013 EC on the JPL Small Body Database.