* Astronomy

The 140 - 310 metre wide asteroid 2013 XA4 will make a close pass (43.7 lunar distances, 0.1124 AU), travelling at 7.44 km/second, to the Earth-Moon system on the 22nd December 2013 @ 10:07 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).