2013 - A meteor explodes over Russia, injuring 1,500 people as a shock wave blows out windows and rocks buildings. This happens unexpectedly only hours before the expected closest ever approach of the larger and unrelated asteroid 2012 DA14. The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural region in Russia on 15 February 2013 at about 03:20 UTC. It was caused by an approximately 60-foot, 9,100-ton (10,000-short-ton) near-Earth asteroid that entered the atmosphere at a shallow 18©\degree angle with a speed relative to Earth of 43,000 mph. The light from the meteor was briefly brighter than the Sun, visible as far as 60 miles away. It was observed in a wide area of the region and in neighboring republics. Some eyewitnesses also reported feeling intense heat from the fireball. The object exploded in a meteor air burst over Chelyabinsk Oblast, at a height of about 18 miles (97,000 feet). The explosion generated a bright flash, producing a hot cloud of dust and gas that penetrated to 86,000 feet, and many surviving small fragmentary meteorites. Most of the object's energy was absorbed by the atmosphere, creating a large shock wave. The asteroid had a total kinetic energy before atmospheric impact equivalent to the blast yield of 400¨C500 kilotons of TNT (1.7¨C2.1 petajoules), estimated from infrasound and seismic measurements. This was approximately 30 times as much energy as that released by the atomic bomb detonated at Hiroshima. The object approached Earth undetected before its atmospheric entry, in part because its radiant (source direction) was close to the Sun. 1,491 people were injured seriously enough to seek medical treatment. Around 7,200 buildings in six cities across the region were damaged by the explosion's shock wave, and authorities scrambled to help repair the structures in sub-freezing temperatures. It is the largest known natural object to have entered Earth's atmosphere since the 1908 Tunguska event, which destroyed a wide, remote, forested, and very sparsely populated area of Siberia. The Chelyabinsk meteor is also the only meteor confirmed to have resulted in injuries. No deaths were reported.