NASA releases estimates on exploding meteor that shook city

PITTSBURGH (AP) — Scientists have released a size and mass estimate of an exploding meteor believed to have caused a loud boom and shaking of the ground across portions of suburban Pittsburgh on New Year’s Day. NASA’s Meteor Watch social media site says a nearby infrasound station registered the blast wave from the meteor as it broke apart — releasing energy equivalent to about 30 tons of TNT. Officials said a “reasonable assumption” of the speed of the meteor at about 45,000 miles per hour would allow a “ballpark” estimate of its size as about a yard in diameter with a mass close to half a ton.