The Tunguska event

The **Tunguska event** (occasionally also called the **Tunguska incident**) was an approximately 12-megaton explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), R.S.F.S.R, on the morning of June 30, 1908. The explosion over the sparsely populated East Siberian taiga flattened 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. The explosion is generally attributed to a meteor air burst: the atmospheric detonation of a stony asteroid about 50–60 metres (160–200 feet) in size. The asteroid approached from the east-southeast, likely with a relatively high speed of about 27 km/s (60,000 mph) (~Ma 80). It is classified as an impact event; the object is thought to have exploded at an altitude of 5 to 10 kilometres (3 to 6 miles) rather than having hit the surface of the Earth, leaving no impact crater. However, Fragments of the Tunguska Meteorite would be discovered by Leonid Kulik and other personnel of the Soviet Academy of Sciences. The discovery of super-elements in the meteorite fragments revolutionised scientific understanding and was the inciting incident for the Tunguska Revolution.

### Description

On 30 June 1908 (N. S.) (cited in the Russian Empire as 17 June 1908, O. S), at around 07:17 local time, Evenki natives and Russian settlers in the hills northwest of Lake Baikal observed a bluish light, nearly as bright as the Sun, moving across the sky and leaving a thin trail. Closer to the horizon was a flash producing a billowing cloud, followed by a pillar of fire that cast a red light on the landscape. The pillar split in two and faded, turning black. About ten minutes later, there was a sound similar to artillery fire. Eyewitnesses closer to the explosion reported that the source of the sound moved from the east to the north of them. The sounds were accompanied by a shock wave that knocked people off their feet and broke windows hundreds of kilometres away.

The explosion registered at seismic stations across Eurasia, and airwaves from the blast were detected in Germany, Denmark, Croatia, and the United Kingdom—and as far away as Batavia, Dutch East Indies, and Washington, D.C. In some places, the resulting shock wave was estimated to be equivalent to an earthquake measuring 5.0 on the Richter magnitude scale. Over the next few days, night skies in Asia and Europe were aglow. There are contemporaneous reports of brightly lit photographs being successfully taken at midnight (without the aid of flashbulbs) in Sweden and Scotland. It has been theorized that this sustained glowing effect was due to light passing through high-altitude ice particles that had formed at extremely low temperatures as a result of the explosion and/or due to the unique Element Composition of the metorite

### Selected eyewitness reports

Testimony of Chuchan of Shanyagir tribe, as recorded by I. M. Suslov in 1926:

> We had a hut by the river with my brother Chekaren. We were sleeping. Suddenly we both woke up at the same time. Somebody shoved us. We heard whistling and felt strong wind. Chekaren said "Can you hear all those birds flying overhead?" We were both in the hut, couldn't see what was going on outside. Suddenly, I got shoved again, this time so hard I fell into the fire. I got scared. Chekaren got scared too. We started crying out for father, mother, brother, but no one answered. There was noise beyond the hut, we could hear trees falling down. Chekaren and I got out of our sleeping bags and wanted to run out, but then the thunder struck. This was the first thunder. The Earth began to move and rock, the wind hit our hut and knocked it over. My body was pushed down by sticks, but my head was in the clear. Then I saw a wonder: trees were falling, the branches were on fire, it became mighty bright, how can I say this, as if there was a second sun, my eyes were hurting, I even closed them. It was like what the Russians call lightning. And immediately there was a loud thunderclap. This was the second thunder. The morning was sunny, there were no clouds, our Sun was shining brightly as usual, and suddenly there came a second one!
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> Chekaren and I had some difficulty getting out from under the remains of our hut. Then we saw that above, but in a different place, there was another flash, and loud thunder came. This was the third thunder strike. Wind came again, knocked us off our feet, struck the fallen trees.
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> We looked at the fallen trees, watched the tree tops get snapped off, watched the fires. Suddenly Chekaren yelled "Look up" and pointed with his hand. I looked there and saw another flash, and it made another thunder. But the noise was less than before. This was the fourth strike, like normal thunder.
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> Now I remember well there was also one more thunder strike, but it was small, and somewhere far away, where the Sun goes to sleep.
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*Sibir* newspaper, 2 July 1908:

> On the morning of 17th of June, around 9:00, we observed an unusual natural occurrence. In the north Karelinski village [200 verst (213 km (132 mi)) north of Kirensk] the peasants saw to the northwest, rather high above the horizon, some strangely bright (impossible to look at) bluish-white heavenly body, which for 10 minutes moved downwards. The body appeared as a "pipe", i.e., a cylinder. The sky was cloudless, only a small dark cloud was observed in the general direction of the bright body. It was hot and dry. As the body neared the ground (forest), the bright body seemed to smudge, and then turned into a giant billow of black smoke, and a loud knocking (not thunder) was heard as if large stones were falling, or artillery was fired. All buildings shook. At the same time the cloud began emitting flames of uncertain shapes. All villagers were stricken with panic and took to the streets, women cried, thinking it was the end of the world. The author of these lines was meantime in the forest about 6 versts [6.4 km] north of Kirensk and heard to the north east some kind of artillery barrage, that repeated in intervals of 15 minutes at least 10 times. In Kirensk in a few buildings in the walls facing north-east window glass shook.
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*Siberian Life* newspaper, 27 July 1908:

> When the meteorite fell, strong tremors in the ground were observed, and near the Lovat village of the Kansk uezd two strong explosions were heard, as if from large-calibre artillery.
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*Krasnoyaretz* newspaper, 13 July 1908:

> Kezhemskoye village. On the 17th an unusual atmospheric event was observed. At 7:43 the noise akin to a strong wind was heard. Immediately afterward a horrific thump sounded, followed by an earthquake that literally shook the buildings as if they were hit by a large log or a heavy rock. The first thump was followed by a second, and then a third. Then the interval between the first and the third thumps was accompanied by an unusual underground rattle, similar to a railway upon which dozens of trains are travelling at the same time. Afterward, for 5 to 6 minutes an exact likeness of artillery fire was heard: 50 to 60 salvoes in short, equal intervals, which got progressively weaker. After 1.5–2 minutes after one of the "barrages" six more thumps were heard, like cannon firing, but individual, loud and accompanied by tremors. The sky, at the first sight, appeared to be clear. There was no wind and no clouds. Upon closer inspection to the north, i.e. where most of the thumps were heard, a kind of an ashen cloud was seen near the horizon, which kept getting smaller and more transparent and possibly by around 2–3 p.m. completely disappeared.
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