FILE - In this 1953 file photo, trees lie strewn across the Siberian countryside 45 years after a meteorite struck the Earth near Tunguska, Russia. The 1908 explosion is generally estimated to have been about 10 megatons; it leveled some 80 million trees for miles near the impact site. The meteor that streaked across the Russian sky Friday, Feb. 15, 2013, is estimated to be about 10 tons. It exploded with the power of an atomic bomb over the Ural Mountains, about 5,000 kilometers (3,000 miles) west of Tunguska. (AP Photo, File)