An object the size of asteroid 2012 DA14 appears to hit Earth
about once every 1,200 years, Yeomans said. "There really hasn't
been a close approach that we know about for an object of this
size," he added. On its close approach to Earth, it was
predicted the asteroid would be traveling at 7.8 kilometers per
second, roughly eight times the speed of a bullet from a high-
speed rifle, he said. If it had hit our planet -- which was
impossible -- it would have done so with the energy of 2.4
megatons of TNT, Yeomans said. This is comparable to the event
in Tunguska, Russia, in 1908. That asteroid entered the
atmosphere and exploded, leveling trees over an area of 820
square miles -- about two-thirds the size of Rhode Island. Like
that rock, 2012 DA14 would likely not have left a crater. What
else is out there? So, we knew that this particular asteroid
wasn't going to hit us, but how about all of those other giant
rocks floating nearby beyond our atmosphere? NASA says 9,697
objects have been classified as near-Earth