The Tunguska event was a massive explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of June 30, 1908.
Since the 1908 event, there have been an estimated 1,000 scholarly papers (most in Russian) published about the Tunguska explosion.
It has been mentioned numerous times in popular culture, and has also inspired real-world discussion of asteroid impact avoidance. ==Description== On 30 June 1908 (N.
S.) (cited in Russia as 17 June 1908, O.
Suslov in 1926: Sibir newspaper, 2 July 1908: Siberian Life newspaper, 27 July 1908: Krasnoyaretz newspaper, 13 July 1908: ==Scientific investigation== It was not until more than a decade after the event that any scientific analysis of the region took place, in part due to the isolation of the area and significant political upheaval affecting Russia in the 1910s.
The isotopic signatures of carbon, hydrogen, and nitrogen at the layer of the bogs corresponding to 1908 were found to be inconsistent with the isotopic ratios measured in the adjacent layers, and this abnormality was not found in bogs located outside the area.
Suslov in 1926: Sibir newspaper, 2 July 1908: Siberian Life newspaper, 27 July 1908: Krasnoyaretz newspaper, 13 July 1908: ==Scientific investigation== It was not until more than a decade after the event that any scientific analysis of the region took place, in part due to the isolation of the area and significant political upheaval affecting Russia in the 1910s.
S., before the implementation of the Soviet calendar in 1918), at around 07:17 local time, Evenki natives and Russian settlers in the hills northwest of Lake Baikal observed a column of bluish light, nearly as bright as the sun, moving across the sky.
In 1921, the Russian mineralogist Leonid Kulik led a team to the Podkamennaya Tunguska River basin to conduct a survey for the Soviet Academy of Sciences.
Suslov in 1926: Sibir newspaper, 2 July 1908: Siberian Life newspaper, 27 July 1908: Krasnoyaretz newspaper, 13 July 1908: ==Scientific investigation== It was not until more than a decade after the event that any scientific analysis of the region took place, in part due to the isolation of the area and significant political upheaval affecting Russia in the 1910s.
Upon returning, he persuaded the Soviet government to fund an expedition to the suspected impact zone, based on the prospect of salvaging meteoric iron. Kulik led a scientific expedition to the Tunguska blast site in 1927.
Semenov, as recorded by Russian mineralogist Leonid Kulik's expedition in 1930: Testimony of Chuchan of Shanyagir tribe, as recorded by I.
In 1938, Kulik arranged for an aerial photographic survey of the area covering the central part of the leveled forest ().
Positive prints were preserved for further study in the Russian city of Tomsk. Expeditions sent to the area in the 1950s and 1960s found microscopic silicate and magnetite spheres in siftings of the soil.
The 15-megaton (Mt) estimate represents an energy about 1,000 times greater than that of Hiroshima bomb, and roughly equal to that of the United States' Castle Bravo nuclear test in 1954 (which measured 15.2 Mt) and one-third that of the Soviet Union's Tsar Bomba test in 1961.
Trees more distant from the centre had been partly scorched and knocked down in a direction away from the centre, creating a large radial pattern of downed trees. In the 1960s, it was established that the zone of levelled forest occupied an area of , its shape resembling a gigantic spread-eagled butterfly with a "wingspan" of and a "body length" of .
Positive prints were preserved for further study in the Russian city of Tomsk. Expeditions sent to the area in the 1950s and 1960s found microscopic silicate and magnetite spheres in siftings of the soil.
The 15-megaton (Mt) estimate represents an energy about 1,000 times greater than that of Hiroshima bomb, and roughly equal to that of the United States' Castle Bravo nuclear test in 1954 (which measured 15.2 Mt) and one-third that of the Soviet Union's Tsar Bomba test in 1961.
The original negatives of these aerial photographs (1,500 negatives, each ) were burned in 1975 by order of Yevgeny Krinov, then Chairman of the Committee on Meteorites of the USSR Academy of Sciences, as part of an initiative to dispose of flammable nitrate film.
1999, 2003) and that iridium anomalies were also observed (Hou et al.
In 2013, a team of researchers published the results of an analysis of micro-samples from a peat bog near the centre of the affected area, which show fragments that may be of extraterrestrial origin. The Tunguska event is the largest impact event on Earth in recorded history, though much larger impacts have occurred in prehistoric times.
The largest asteroid air burst to be observed with modern instrumentation was the 500-kiloton Chelyabinsk meteor in 2013, which shattered windows and produced meteorites. ==== Glancing impact hypothesis ==== In 2020 a group of Russian scientists used a range of computer models to calculate the passage of asteroids with diameters of 200, 100, and 50 metres at oblique angles across Earth's atmosphere.
A 2019 paper suggests the explosive power of the Tunguska event may have been around 20–30 megatons. Since the second half of the 20th century, close monitoring of Earth's atmosphere through infrasound and satellite observation has shown that asteroid air bursts with energies comparable to those of nuclear weapons routinely occur, although Tunguska-sized events, on the order of 5–15 megatons, are much rarer.
The largest asteroid air burst to be observed with modern instrumentation was the 500-kiloton Chelyabinsk meteor in 2013, which shattered windows and produced meteorites. ==== Glancing impact hypothesis ==== In 2020 a group of Russian scientists used a range of computer models to calculate the passage of asteroids with diameters of 200, 100, and 50 metres at oblique angles across Earth's atmosphere.
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