Tunguska event

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Tunguska event

(tung-guss -kă) A gigantic explosion that occurred at about 7.17 a.m. on June 30, 1908 in the basin of the River Podkamennaya in Tunguska, Central Siberia. Devastation rained over an area 80 km in diameter and eye witnesses up to 500 km away saw in a cloudless sky the flight and explosion of a blindingly bright pale blue bolide. The sound of the explosion reverberated thousands of kilometers away, the explosion air wave recorded on microbarographs going twice round the world. The main explosion had an energy of 5 × 1016 joules and occurred at an altitude of 8.5 km. It was caused by the disintegration of an incoming object, most likely a Fragile Apollo asteroid or a small comet nucleus. When the object encountered the Earth it would have been coming from a point in the dawn sky comparatively close to the Sun and would thus have been most difficult to detect and observe.
References in periodicals archive ?
June 30 is the anniversary of the Tunguska impact, also known as the Tunguska event.
Now the thinking is that these blasts are driven deeper down by their own momentum, an idea first put forward six years ago by Mark Boslough and David Crawford (Sandia National Laboratories) to explain the roughly 2,000 square kilometers of devastation caused by the Tunguska impact in 1908.
Burrows provides an excellent summary of asteroid strikes, from the dinosaur killer to the 1908 Tunguska impact.