The Meteorite Explosion that Shook Chelyabinsk, Russia on February 15, 2013

Russian Meteor — A meteor seen flying over Russia on Feb. 15 at 3:20: 26 UTC impacted Chelyabinsk.

A meteor entered the Earth’s atmosphere and disintegrated in the skies over Chelyabinsk, Russia, at 7:20:26 PM PST, or 10:20:26 PM EST on February 14 (3:20:26 UTC on February 15).

At a news conference on Friday, NASA scientists said the object was a “tiny asteroid”. The trajectory of this meteor differed appreciably from the trajectory of the asteroid 2012 DA14, which hours later made its flyby of Earth, making both objects completely unrelated.

The Russian Emergency Ministry described it as a shower of meteorite debris. However, some unconfirmed reports suggested that Russian air defenses shot down a meteorite. NASA asteroid expert Don Yeomans, head of the agency’s Near-Earth Object Program Office, said that the object which exploded was most likely an exploding fireball known as a bolide.

According to the preliminary information that appeared in the media unidentified flying objects exploded over several cities in Russia, and the object at Chelyabinsk measured 49 feet (15 meters) across, weighing 7,000 tons and released 30 kilotons of energy when it exploded, and the blast waves blew out window glass of buildings in Chelyabinsk, sending dozens to hospitals, disrupted mobile services, and reportedly injured more than 1,000 people. Many dashboard videos appeared online, showing huge fireballs flying over buildings and exploding with a strong blast. Some walls of the Chelyabinsk Zinc Factory that produced 160,000 metric tons of refined zinc and alloys last year collapsed with extensive damage to the plant.

Now NASA says information provided by a worldwide network of sensors has allowed scientists to revise their estimates for the size of the object before entering Earth’s atmosphere to 55 feet (17 meters), weighing about 10,000 tons. Bill Cooke, head of the Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama said the energy released during the explosion amounted to 500 kilotons equal to that of an exploding modern nuclear bomb.

Fresh data collected from five more infrasound stations located around the world helped to generate these new estimates. The first infra-sound recording of the event took place in Alaska – over 6,500 kilometers away from Chelyabinsk. Calculations performed by Peter Brown at the University of Western Ontario, Canada, using infrasound data show the time taken by the object from entering the atmosphere to its disintegration in the air took 32.5 seconds.

Paul Chodas of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California said, “We would expect an event of this magnitude to occur once every 100 years on average ”

The present Russia meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia.