The 64 - 140 metre wide asteroid 1997 GK3 will make a close pass (39.4 lunar distances, 0.1013 AU), travelling at 10.45 km/second, to the Earth-Moon system on the 6th April 2014 @ 09:10 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).