On March 23, 1989 the 300-metre wide Apollo asteroid 4581 Asclepius (1989 FC) missed the Earth by 700,000 kilometers passing through the exact position where the Earth was only 6 hours before. If the asteroid had impacted it would have created the largest explosion in recorded history, 12 times as powerful as the Tsar Bomba, the most powerful nuclear bomb ever exploded.
The 220 - 490 metre wide asteroid Asclepius will make a close pass (46.2 lunar distances, 0.1188 AU), travelling at 7.58 km/second, to the Earth-Moon system on the 25th August, 2013 @ 15:00 UT ±00:01.
The 220 - 490 metre wide asteroid Asclepius will make a close pass (42.0 lunar distances, 0.1079 AU), travelling at 13.48 km/second, to the Earth-Moon system on the 16th August, 2012 @ 08:46 UT ±00:01.
