On February 15, 2013, a rocky asteroid entered Earth atmosphere over Chelyabinsk Oblast, Russia. It remains the largest documented atmospheric impactor since the 1908 Tunguska event. Here is what sensor arrays, infrasound detectors, and field recovery expeditions measured:
- Pre-atmospheric diameter: 18 to 20 meters, roughly the length of two city buses parked end to end.
- Pre-entry mass: Approximately 11,000 to 13,000 metric tons, heavier than the Eiffel Tower steel framework.
- Atmospheric entry speed: 19.16 kilometers per second (69,000 km/h or Mach 56).
- Peak radiated altitude: 29.7 kilometers above the ground, where ram pressure overwhelmed the rock tensile strength.
- Total kinetic impact energy: 440 to 500 kilotons of TNT equivalent, roughly 30 times the energetic yield of the 1945 Hiroshima detonation.
- Recovered meteorite fragments: An LL5 ordinary chondrite. The largest single fragment, weighing 654 kilograms (1,442 pounds), was hauled from the bottom of Lake Chebarkul in October 2013 and is displayed at the State Historical Museum of the Southern Urals.
The primary damage on the ground was caused not by falling rocks, but by the supersonic atmospheric blast wave that arrived two to three minutes after the visual flash. The pressure front blew out windows across 7,200 buildings in six cities, causing indirect injuries to approximately 1,500 people, primarily from flying glass shards.