Where did that Russian meteor come from?

New data from NASA shows that the meteor that exploded over Chelyabinsk, Russia, on Feb. 15 has been crossing the Earth’s orbit for thousands of years. But scientists couldn’t see it coming with ground-based telescopes, mostly because it was hidden in the sun’s glare. NASA also said the blast was the equivalent of 500 kilotons of TNT — roughly 30 times the energy released by the atomic bomb dropped on Hiroshima. The fireball shattered windows across the Russian city, injuring about 1,200 people and causing about $33 million in property damage.