Feb. 18, 2013: In this frame grab taken from AP video, a researcher touches a piece of a meteorite in a laboratory in Yekaterinburg. (AP Photo/ AP Video)
Feb.18, 2013: Pieces of a meteorite are seen in a laboratory in Yekaterinburg. Researchers from the Urals Federal University, based in Yekaterinburg, have determined that the small stone-like pieces found near Lake Cherbarkul in the Chelyabinsk region are pieces of the meteorite that exploded over the region Feb. 15. (AP Photo/ The Urals Federal University Press Service, Alexander Khlopotov)
Feb.18, 2013: A researcher examines pieces of a meteorite in a laboratory in Yekaterinburg. A total of 53 pieces have been brought for analysis to the university lab, the largest is one centimeter in diameter, the smallest is about one millimeter. The Cyrillic writing reads, "Meteorite Chebarkul." (AP Photo/ The Urals Federal University Press Service, Alexander Khlopotov)
Feb.18, 2013: Researchers from the Urals Federal University, based in Yekaterinburg, have determined that the small stone-like pieces found near Lake Cherbarkul in the Chelyabinsk region are pieces of the meteorite that exploded over the region Feb. 15. A total of 53 pieces have been brought for analysis to the university in Yekaterinburg. (AP Photo/ The Urals Federal University Press Service, Alexander Khlopotov)
Feb.18, 2013: Researchers from the Urals Federal University, based in Yekaterinburg, have determined that the small stone-like pieces found near Lake Cherbarkul in the Chelyabinsk region are pieces of the meteorite that exploded over the region Feb. 15. (AP Photo/ The Urals Federal University Press Service, Alexander Khlopotov)
Feb.18, 2013: Researchers from the Urals Federal University, based in Yekaterinburg, have determined that the small stone-like pieces found near Lake Cherbarkul in the Chelyabinsk region are pieces of the meteorite that exploded over the region Feb. 15. A total of 53 pieces have been brought for analysis to the university in Yekaterinburg. The largest one is one centimeter in diameter, the smallest is about one millimeter. (AP Photo/ The Urals Federal University Press Service)
Feb. 15, 2013: A meteorite contrail is seen over a vilage of Bolshoe Sidelnikovo, 50 km out side of Chelyabinsk. A meteor streaked across the sky of Russias Ural Mountains on Friday morning, causing sharp explosions and injuring hundreds. (AP Photo/ Nadezhda Luchinina, E1.ru)
Feb. 15, 2013: In this combo made from frame grabs from dashboard camera video, a meteor streaks through the sky over Chelyabinsk, about 930 miles east of Moscow. (AP Photo/AP Video)
Friday, Feb. 15, 2013: A meteorite contrail is seen over Chelyabinsk. (AP Photo/Chelyabinsk.ru)
Feb. 15, 2013: A circular hole in the ice of Chebarkul Lake where a meteor reportedly struck the lake near Chelyabinsk, about 930 miles east of Moscow, Russia. (AP Photo)
Feb. 15, 2013: A circular hole in the ice of Chebarkul Lake where a meteor reportedly struck the lake near Chelyabinsk, about 930 miles east of Moscow. (AP Photo)
Feb. 15, 2013: Municipal workers repair damaged electric power circuit outside a zinc factory building with about 6,000 square feet of a roof collapsed after a meteorite exploded over in Chelyabinsk region. (AP Photo/ Oleg Kargapolov, Chelyabinsk.ru)