Moscow, Russia -- A Russian health official says nearly 1,000 people have sought help for injuries caused by a meteor that exploded in the sky, blasting out countless windows.
Chelyabinsk health chief Marina Moskvicheva, said Friday that 985 people in her city had asked for medical assistance. The Interfax news agency quoted her as saying 43 were hospitalized.
The Russian Academy of Sciences said the meteor -- estimated to be about 10 tons -- entered the Earth's atmosphere going at least 54,000 kph (33,000 mph). It shattered about 30-50 kilometers (18-32 miles) above the ground, releasing several kilotons of energy above the Ural Mountains.
Amateur video broadcast on Russian television showed an object speeding across the sky just after sunrise, leaving a thick white contrail and an intense flash.
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. They often hit the ground at tremendous speed -- up to about 19,000 miles an hour, according to the European Space Agency. That releases a huge amount of force.
Experts say smaller strikes happen five to 10 times a year. Large impacts such as the one Friday in Russia are rarer but still occur about every five years, according to Addi Bischoff, a mineralogist at the University of Muenster in Germany. Most of these strikes happen in uninhabited areas where they don't cause injuries to humans.