Chelyabinsk meteor airburst

The object entered Earth's atmosphere at about 03:20 UTC on 15 February 2013, over the Kazakhstan–Russia border, and travelled northwest toward the Chelyabinsk region. NASA's Jet Propulsion Laboratory estimated its initial size at roughly 17–20 metres. It entered at high speed on a shallow trajectory, heated and fragmented as it passed through the atmosphere. NASA's later estimates put its peak brightness about 23 kilometres above the ground and its total energy near 440 kilotons of TNT; NASA describes these energy and size figures as approximate estimates.

The airburst produced a bright flash and a shock wave. The Planetary Society reports that the wave damaged thousands of buildings across six cities and sent about 1,500 people to hospitals and clinics, with many injuries caused by shattered window glass. The explosion occurred high in the atmosphere, where much of its energy was absorbed before reaching the ground.

Dashboard cameras and other video recordings captured the meteor's luminous trail and flash, while infrasound detectors and government sensors provided additional observations. Meteorite fragments recovered in the region provided evidence about the object's composition. A comprehensive scientific study combined observations from astronomy, planetary science, geophysics, meteorology, meteorite analysis and social-science surveys to reconstruct the event and assess damage.

The asteroid was not identified before atmospheric entry. NASA notes that its approach direction was within about 15 degrees of the Sun's direction, an area of the sky that asteroid-search telescopes cannot readily scan. The event was unrelated to asteroid 2012 DA14, which made a close Earth flyby later that day: the two bodies had different approach directions and orbits. Chelyabinsk highlighted the value of surveying near-Earth objects and understanding airburst hazards.