The 39 - 88 metre wide asteroid 2018 GR1 will make a close pass (18.1 lunar distances, 0.04673 AU), travelling at 16.36 km/second, to the Earth on the 21st April 2018 @ 19:53 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).