A meteor that blazed across southern Urals in February was the largest recorded meteor strike in more than a century. More than 1,600 people were injured by the shock wave from the explosion, estimated to be as strong as 20 Hiroshima atomic bombs, as it landed near the city of Chelyabinsk.
Scientists on Wednesday recovered what could be the largest part of this meteor from Chebarkul Lake outside the city. They weighed it using a giant steelyard balance, which displayed 570 kilograms (1,256 pounds) before it broke.
Sergei Zamozdra, an associate professor at Chelyabinsk State University, told Russian television the excavated fragment was definitely a chunk of the meteor.
While NASA estimated the meteor was only about the size of a bus and weighed an estimated 7,000 tons when it entered the atmosphere, 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.
The largest recorded meteor strike in more than a century occurred hours before a 150-foot asteroid passed within about 17,000 miles (28,000 kilometers) of Earth. The European Space Agency said its experts had determined there was no connection between the asteroid and the Russian meteor - just cosmic coincidence.
The meteor above western Siberia entered the Earth's atmosphere about 9:20 a.m. local time at a hypersonic speed of at least 33,000 mph (54,000 kph) and shattered into pieces about 30-50 kilometers (18 to 32 miles) high, the Russian Academy of Sciences said. NASA estimated its speed at about 40,000 mph, said it exploded about 12 to 15 miles high, released 300 to 500 kilotons of energy and left a trail 300 miles long.
"There was panic. People had no idea what was happening," said Sergey Hametov of Chelyabinsk, about 1,500 kilometers (930 miles) east of Moscow in the Ural Mountains.
"We saw a big burst of light, then went outside to see what it was and we heard a really loud, thundering sound," he told The Associated Press by telephone.
The shock wave blew in an estimated 100,000 square meters (more than 1 million square feet) of glass, according to city officials, who said 3,000 buildings in Chelyabinsk were damaged. At a zinc factory, part of the roof collapsed.
Scientists estimated the meteor unleashed a force 20 times more powerful than the Hiroshima bomb, although the space rock exploded at a much higher altitude. Amy Mainzer, a scientist at NASA's Jet Propulsion Laboratory, said the atmosphere acted as a shield.
The shock wave may have shattered windows, but "the atmosphere absorbed the vast majority of that energy," she said.
Emergency Situations Ministry spokesman Vladimir Purgin said many of the injured were cut as they flocked to windows to see what caused the intense flash of light, which momentarily was brighter than the sun.