Published on Feb 15, 2013

The Russian Urals region has been stricken by a sudden cosmic attack. Unidentified flying objects exploded over several major cities, including Chelyabinsk, where the blast waves blew out windows and disrupted mobile connections.

Russian scientists investigating the meteorite explosion in the Urals explained the nature of the event that caused havoc in the region. NASA meanwhile said that the shockwave from the blast was equivalent to a 300-kiloton explosion. The object was identified as a solitary 10-ton bolide by the Russian Academy of Sciences (RAN). Bolides, or bright fireballs, are large meteors that explode in the lower atmosphere, and unlike meteorite showers they can be dangerous, scientists explained. The Chelyabinsk fireball entered the atmosphere moving at a speed of about 20 km/s. The object, which was several meters in diameter, then burst into pieces at a height of 30-50 km above the ground, RAN reported. Three consecutive explosions shattered the meteorite further. Large fragments moving at a high speed caused a powerful flash and a strong shockwave, with most of its energy released at a height of 5 to 15 km above the earth, with the atmosphere absorbing most of that energy.

Researchers including Prof. Peter Brown of the University of Western Ontario along with NASA experts have conducted a preliminary analysis of the event. "Here is what we know so far," says Bill Cooke, head of NASA's Meteoroid Environment Office. "The asteroid was about 15 meters in diameter and weighed approximately 7000 metric tons. It struck Earth's atmosphere at 40,000 mph (18 km/s) and broke apart about 12 to 15 miles (20 to 25 km) above Earth's surface. The energy of the resulting explosion was in the vicinity of 300 kilotons of TNT."