Security camera footage of a building door being blown open by the shock wave produced by the explosion of the Chelabinsk meteor. This object entered the atmosphere on the morning of 15th February 2013, and exploded at an altitude of some 29.7 kilometres, causing a shock wave that shattered windows and damaged buildings, and caused nearly 1500 injuries. Scientists estimated that the meteorite weighed around 12, 000 tonnes, had a diameter of around 20 metres, and entered the atmosphere at a speed of 19 kilometres per second. The main air burst had an energy of nearly 500 kilotons, some thirty times greater than the atomic bomb dropped on Hiroshima.