The 150 - 340 metre wide asteroid 2007 PB8 will make a close pass (65.5 lunar distances, 0.1682 AU), travelling at 14.51 km/second, to the Earth-Moon system on the 14th September, 2012 @ 12:23 UT ±00:01.
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The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).