The Tunguska event was a large explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of 30 June 1908 (NS).[1][2]The explosion over the sparsely populated Eastern Siberian Taigaflattened an estimated 80 million trees over an area of 2,150 km2(830 sq mi) of forest, and eyewitness reports suggest that at least three people may have died in the event.[3][4][5][6][7] The explosion is generally attributed to the air burst of a stony meteoroid about 100 metres (330 feet) in size.[8]:p. 178 It is classified as an impact event, even though no impact crater has been found; the object is thought to have disintegrated at an altitude of 5 to 10 kilometres (3 to 6 miles) rather than to have hit the surface of the Earth.[9]
Due to the remoteness of the site and the limited instrumentation available at the time of the event, modern scientific interpretations of its cause and magnitude have relied chiefly on damage assessments and geological studies conducted many years after the fact. Studies have yielded different estimates of the meteoroid's size, on the order of 50 to 190 metres (160 to 620 feet), depending on whether the body entered with a low or high speed.[10] It is estimated that the shock wave from the air burst would have measured 5.0 on the Richter magnitude scale, and estimates of its energy have ranged from 3–30 megatons of TNT (13–126 petajoules). An explosion of this magnitude would be capable of destroying a large metropolitan area.[11] Since the 1908 event, there have been an estimated 1,000 scholarly papers (most in Russian) published about the Tunguska explosion. In 2013, a team of researchers published the results of an analysis of micro-samples from a peat bog near the center of the affected area which show fragments that may be of meteoritic origin.[12][13]
The Tunguska event is the largest impact event on Earth in recorded history, though much larger impacts have occurred in prehistoric times. It has been mentioned numerous times in popular culture, and has also inspired real-world discussion of asteroid impact avoidance.
