NASA estimates metrics of exploding meteor that shook ground

PITTSBURGH (AP) — Scientists say a meteor that caused an earthshaking boom across suburban Pittsburgh on New Year’s Day exploded in the atmosphere with an energy blast equivalent to an estimated 30 tons of TNT. NASA’s Meteor Watch social media site said late Sunday that a “reasonable assumption” of the speed of the meteor at about 45,000 mph would allow a “ballpark” estimate of its size as about a yard in diameter with a mass close to half a ton. Scientists say if not for the cloudy weather, it would have been easily visible in the daytime sky — maybe about 100 times the brightness of the full moon.