What happened
On the morning of February 15, 2013, at 9:20 a.m. local time, residents of the Urals saw a fireball brighter than the Sun in the sky, trailing a long, smoky tail. A meteoroid roughly 20 meters across entered the atmosphere at about 19 km/s and exploded at an altitude of about 30 km south of Chelyabinsk. Tens of seconds later the shock wave arrived, shattering windows and damaging more than 7,000 buildings in six cities; about 1,500 people were injured, mainly by flying glass, but no one was killed. The flyby was captured by numerous car dashcams and other cameras, making it the best-documented event of its kind in history. In October 2013, a meteorite fragment weighing more than half a ton was raised from the bottom of Lake Chebarkul.
Witnesses
Thousands of residents of Chelyabinsk and Sverdlovsk oblasts and of northern Kazakhstan; the explosion was also recorded by infrasound stations around the world.
Explanations and hypotheses
The event is fully explained: it was a small asteroidal meteoroid, an LL ordinary chondrite, with a mass of about 12,000–13,000 tons. The explosion released energy estimated at 400–500 kilotons of TNT – several dozen times more than the bomb dropped on Hiroshima. The object approached from the direction of the Sun, which is why no one spotted it in advance. The event accelerated work on systems for detecting hazardous asteroids.
Explained The phenomenon has a widely accepted, down-to-earth explanation.
More: Wikipedia (pl) Wikipedia (en)