A meteorite   flew fast across the sky and exploded over central Russia on Friday, raining fireballs over a vast area and causing a shock wave that smashed windows, damaged buildings and injured l,200 people. People heading to work in Chelyabinsk heard what sounded like an explosion, saw a bright light and then felt the shock wave. According to Russian space agency Roscosmos, the fireball, travelling at a speed of 30km per second, had burnt very brightly across the horizon, leaving a long white trail that could be seen as far as 200km away. Car alarms went off, thousands of windows shattered and mobile phone networks were disrupted. "I was driving to work, it was quite dark, but it suddenly became as bright as if it were day," said Viktor Prokofiev, 36, a resident of Yekaterinburg in the Urals Mountains. "I felt like I was blinded by headlights." The meteorite, which weighed about 20 tons and may have been made of iron, entered Earth's atmosphere and broke apart 30-50km above ground, according to Russia's Academy of Sciences. The energy released when it entered the Earth's atmosphere was about several thousand tons, the academy said, the power of a small atomic weapon exploding. No deaths were reported, but the Emergencies Ministry said 20,000 rescue and clean-up workers were sent to the region after President Vladimir Putin told Emergencies Minister Vladimir Puchkov to ease the disruption and help the victims. The Interior Ministry said about l,200 people had been injured, at least 200 of them children, and most from broken pieces of glass."While events this big are rare, an impact that could cause damage and death could happen every century or so. Unfortunately there is absolutely nothing we can do to stop impacts." It can be inferred that the loss caused by meteorites   _  .
is nearly unavoidable happens every few years can be avoided is hard to estimate