The 13 - 28 metre wide asteroid 2014 SS260 will make a close pass (2.8 lunar distances, 0.0072 AU), travelling at 13.44 km/second, to the Earth-Moon system on the 28th September 2014 @ 19:49 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).