The Russian Academy of Sciences says the meteor entered the Earth's atmosphere at a speed of at least 33,000 mph, causing shock waves that shattered windows and damaged buildings. At eight times the speed of a rifle bullet, the meteorite streaked across the skies over the Ural Mountains.
The meteor caused widespread panic, and many locals thought they were being attacked. Nearly 20,000 troops were called to the scene, and three aircraft surveyed damage from the sky.
"There was panic. People had no idea what was happening," said Sergey Hametov, a resident of Chelyabinsk, a city of 1 million.
The blast occurred in an industrial city 950 miles east of Moscow at about 9:20 a.m. local time. NASA officials say they weren't tracking this meteor because it was so small.
"It's an amazing event. It is a constant reminder that these asteroids are flying through the inter-solar system, and it's very important for us to study them and to keep track of them," said Dante Lauretta, NASA principal investigator. "This seems like it was a relatively small object that came in, it burst in the atmosphere, creating that sonic wave."
Despite the large number of injuries reported, authorities say most of them are not serious.
Some fragments fell in a reservoir outside the town of Cherbakul, the regional governor's office said, according to the ITAR-Tass news agency. The crash left a 26-foot crater in the ice.
Meteors typically cause sizeable sonic booms when they enter the atmosphere because they are traveling much faster than the speed of sound. Injuries on the scale reported Friday, however, are very rare.
What's the difference between a meteor and a meteorite? Meteors are pieces of space rock, usually from larger comets or asteroids, which enter the Earth's atmosphere. Many are burned up by the heat of the atmosphere, but those that survive and strike the Earth are called meteorites.
Russian news reports noted that the meteor hit less than a day before the asteroid 2012 DA14 made the closest recorded pass of an asteroid -- about 17,150 miles. However, the European Space Agency, in a post on its Twitter account, said its experts had determined there was no connection.
The Associated Press contributed to this report.
