In a chilling coincidence, a meteor exploded above Russia's Ural Mountains just hours before the asteroid was due to zoom past the planet. Scientists the world over, along with NASA, insisted the meteor had nothing to do with the incoming asteroid since they appeared to be traveling in opposite directions. The asteroid is a much more immense object that was expected to miss Earth by 17,150 miles. But this rock could still do immense damage if it struck given its 143,000-ton heft, releasing the energy equivalent of 2.4 million tons of TNT and wiping out 750 square miles. By comparison, NASA estimated that the meteor over Russia was about 15 meters (49 feet) wide and weighed about 7,000 tons before it hit the atmosphere. It was about one-quarter the size of the passing asteroid. As for the back-to-back events, "this is indeed very rare and it is historic," said Jim Green, NASA's director of planetary science. While DA14 is about half the length of a football field, the exploding meteor "is probably about on the 15-yard line," he said. Now that's pretty big. That's typically a couple times bigger than the normal influx of meteorites that create these fireballs," he said in an interview on NASA TV. These fireballs happen about once a day or so, but we just don't see them because many of them fall over the ocean or in remote areas. This one was an exception. As the countdown to asteroid DA14's close approach entered the final hours, NASA noted on its website that the path of the meteor appeared to be quite different than that of the asteroid, making the two objects "completely unrelated." The meteor seemed to be traveling from north to south, while the asteroid was due to pass from south to north - in the opposite direction. Even after Friday's scare, scientists remained certain that asteroid DA14 would not impact Earth. And chances were extremely remote, they said, that it will run into any of the satellites orbiting 22,300 miles up. Friday's meteor - just 16 hours in advance of DA14's point of closest encounter - further strengthened the asteroid-alert message. If a killer asteroid was, indeed, incoming, a spacecraft could, in theory, be launched to nudge the asteroid out of Earth's way, changing its speed and the point of intersection.