We can compare the Tunguska event with the fireball seen during the impact of the Chelyabinsk meteor earlier this year. Although much less powerful than Tunguska, the Chelyabinsk event was similar. A low-angle approach broke up the body, leaving fragments that were found over the vast expanse of Eurasia. More than 1,000 people were injured, some drawn to windows by the flash of the fireball and then hit by the shock wave that followed. The Tunguska devastation was not investigated for 19 years, partly because of a lack of resources. In contrast, the Chelyabinsk meteorite attracted immediate attention. Dashboard cameras captured the trajectory and brightness of the fireball, while CCTV networks provided fixed reference points. The US space agency NASA has now been able to identify the origins of the meteorite. The low-frequency rumble of the Chelyabinsk event travelled twice around the globe. The data demonstrate that the energy of the impact was equivalent to a 460 kiloton (TNT) bomb ... Читать дальше »