Chelyabinsk meteor bigger than thought

Nature : According to two papers published in Nature and one published in Science this week, the meteor that struck Chelyabinsk, Russia, on 15 February was bigger and brighter than earlier estimates. Based on eyewitness testimony and video footage captured by security and dashboard cameras, scientists have now calculated that the meteor may have been twice as heavy as initially estimated—on the order of 12 000–13 000 metric tons—and exploded with an energy equivalent to 500 kilotons of TNT. About 1500 people were injured, including some who had received sunburns from the UV light emitted. Thousands of windows were shattered, and other building damage was reported. The researchers add that such meteor impacts may be more common than previously assumed: Rather than occurring once every 150 years, a Chelyabinsk-type meteor may actually strike once every few decades.