The rock, 2004 VD17, is about 500 metres (yards) long and has a mass of nearly a billion tonnes, which — if it were to impact — would deliver 10,000 megatonnes of energy, equivalent to all the world’s nuclear weapons.
Spotted on November 27 2004, VD 17 was swiftly identified as rock that potentially crossed Earth’s orbit, with a 1 in 3,000 risk of collision on May 4 2102.
Further observations and calculations have prompted the risk on that day to be upgraded to “a bit less than 1 in 1,000,” said NASA Near-Earth Object (NEO) expert David Morrison in an emailed circular.
“The risk of an impact within the next century (is) higher than that of any other known asteroid,” he said, stressing however that the likelihood of a hit was small.
“Fortunately, it is nearly a century before the close pass from VD 17. This should provide ample time to refine the orbit and, most probably, determine that the asteroid will miss the Earth.” MORE