Near-Earth object the largest explosion in recorded history, equivalent to 20,000 megatons of TNT. It attracted widespread attention because it was discovered only after the closest approach. In March 1998, early orbit calculations for recently discovered asteroid showed a potential 2028 close approach from the Earth, well within the orbit of the Moon, but with a large error margin allowing for a direct hit. Further data allowed a revision of the 2028 approach distance to , with no chance of collision. By that time, inaccurate reports of a potential impact had caused a media storm. From the late 1990s, a typical frame
Near-Earth object February 15, 2013, the asteroid 367943 Duende () passed approximately above the surface of Earth, closer than satellites in geosynchronous orbit. The asteroid was not visible to the unaided eye. This was the first close passage of an object discovered during a previous passage, and was thus the first to be predicted well in advance. Some NEOs are of special interest because they can be physically explored with lower mission velocity than is necessary for even the Moon, due to their combination of low velocity with respect to Earth and weak gravity. They may present interesting scientific opportunities both for