Meteor explodes above Russian city

  

Video from YouTube shows the explosion of the meteor from a number of cameras.

Edited from CBC News:

With a blinding flash and a booming shock wave, a meteor blazed across the western Siberian sky Friday near the Russian city of Chelyabinsk and exploded with the force of 20 atomic bombs, injuring more than 1,000 people as it blasted out windows and spread panic  (fear) in the city of 1 million.

"There was panic. People had no idea what was happening," said Sergey Hametov of Chelyabinsk, about 1,500 kilometers east of Moscow in the Ural Mountains.

Windows damaged by the meteor explosion

Meteoroids are small pieces of space debris — usually parts of comets or asteroids — that are on a collision course with the Earth. They become meteors when they enter the Earth's atmosphere. Most meteors burn up in the atmosphere, but if they survive the frictional heating and strike the surface of the Earth they are called meteorites. 

 
While NASA estimated the meteor was only about the size of a bus and weighed an estimated 7,000 tons, the fireball it produced was dramatic. Video shot by startled residents of the city of Chelyabinsk showed its streaming contrails as it arced toward the horizon just after sunrise, looking like something from a world-ending science-fiction movie.  It was the largest recorded meteor strike in more than a century.

The meteor above western Siberia entered the Earth's atmosphere about 9:20 a.m. local time at a hypersonic speed of at least 54,000 km/h and shattered into pieces about 30-50 kilometers high, the Russian Academy of Sciences said. NASA estimated its speed at about 65,000 km/h, said it exploded about 30 to 38 kilometers above the ground, released 300 to 500 kilotons of energy and left a trail 485 kilometres long.

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How much is 300 kilotons of explosive energy?

Atomic bombs (2) dropped on Japan in 1945 -  Equal to 15 kilotons of explosive force (15,000 tons).

The Chelyabinsk meteor explosion was equal to at least 20 atomic bombs. 

People walk along a road in Hiroshima 1945. All the buildings were destroyed by the atomic bomb.

For a 10 kiloton blast at the height where it would produce the most damage, severe damage to frame (wooden) houses would occur out to 1.6 km and moderate damage to 2.4 km. A 10 kiloton blast would produce a fireball of about 300 meters in diameter and would cause moderate flash burns (second degree) at a range of about 2.4 km. A second-degree burn includes blisters, a darker tone and a shiny, moist appearance.

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The shock wave broke an estimated 100,000 square metres of glass, according to city officials, who said 3,000 buildings in Chelyabinsk were damaged. At a factory, part of the roof collapsed.

The meteor's shockwave damaged around 3,000 buildings including this zinc factory, where about 600 square metres of the roof collapsed.

The Interior Ministry said about 1,100 people sought medical care after the shock wave and 48 were hospitalized. Most of the injuries were caused by flying glass, officials said. A Chelyabinsk resident, Alexander Yakovets, told CBC News he was woken in his eighth-floor apartment by a "really horrible sound" that he first thought might have been a terrorist attack or a military exercise. He said he saw a very bright light and heard multiple explosions.

 NASA said the Russian fireball was the largest reported since 1908, when a meteor hit Tunguska, Siberia, and flattened an estimated 80 million trees. Chelyabinsk is about 5,000 kilometers west of Tunguska. The Tunguska blast, attributed to a comet or asteroid fragment, is generally estimated to have been about 10 megatons. For the full story, click here

Chelyabinsk

Trees flattened by the Tunguska meteor blast in 1908

Click here for more about the even bigger Tunguska explosion and what different scientist think may have caused it: https://www.youtube.com/watch?v=sF8HKCuA3DQ