* Astronomy

The 230 - 520 metre wide asteroid 2013 WU45 will make a close pass (59.0 lunar distances, 0.1517 AU), travelling at 21.96 km/second, to the Earth-Moon system on the 19th December, 2013 @ 19:52 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).