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 objects, or NEOs, as of February 12. Near-Earth objects are comets or asteroids in orbits that allow them to enter Earth's neighborhood.
There's an important distinction between these two types of objects: Comets are mostly water, ice and dust, while asteroids are mostly rock or metal. Both comets and asteroids have hit Earth in the past.
More than 1,300 near-Earth objects have been classified as potentially hazardous to Earth, meaning that someday they may come close or hit our home planet. NASA is monitoring these objects and updating their locations as new information comes in. Right now, scientists aren't warning of any imminent threats.
Yeomans and colleagues are using telescopes on the ground and in space to nail down the precise orbit of objects that might threaten Earth and predict whether the planet could be hit.