Superbolide
A superbolide is an extraordinarily bright bolide, usually defined as reaching magnitude −17 or brighter.
Astronomers measure brightness on the magnitude scale, where smaller numbers mean brighter objects: Venus is about −4 and the full Moon about −13. A superbolide is a bolide that reaches roughly magnitude −17 or brighter, outshining the full Moon by roughly forty times. Such objects are usually metre-sized or larger before they enter the atmosphere.
The best-documented superbolide fell over Chelyabinsk, Russia, on 15 February 2013. An asteroid about 18 metres across entered at roughly 19 kilometres per second and burst between about 20 and 30 kilometres up, briefly appearing brighter than the Sun. The shock wave broke windows across the city and around 1,500 people were hurt, mostly by flying glass. Thousands of stones fell, classified as an LL5 ordinary chondrite, including a piece of about 540 kilograms raised from Lake Chebarkul later that year.
Superbolides are detected by dashcams and security cameras, by satellites that watch for flashes, and by infrasound stations that pick up very low-frequency pressure waves. Together these let scientists estimate the energy released.
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