The 240 - 540 metre wide asteroid 2008 YJ3 will make a close pass (40.0 lunar distances, 0.1028 AU), travelling at 17.14 km/second, to the Earth-Moon system on the 10th July, 2010 @ 02:15 UT. See more
The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).