Smile of the Day Thursday June 30, 2022: The Tunguska Event

On this Day:

On June 30, 1908 A giant fireball, most likely caused by the air burst of a large meteoroid or comet, flattens 80 million trees near the Stony Tunguska River in Yeniseysk Governorate, Russia, in the largest impact event in recorded history.

The Tunguska event (occasionally also called the Tunguska incident) was a ~12 megaton explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of June 30, 1908. The explosion over the sparsely populated Eastern 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 explosion of a stony meteoroid about 50–60 metres (160–200 feet) in size.  The meteoroid approached from the east-southeast, and likely with a relatively high speed of about 27 km/s (60,000 mph) (~Ma 80). 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.

The Tunguska event is the largest impact event on Earth in recorded history, though much larger impacts have occurred in prehistoric times. An explosion of this magnitude would be capable of destroying a large metropolitan area. 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.), 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, there 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 to 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 air waves 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. It is estimated that, in some places, the resulting shock wave was 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—a phenomenon that decades later was reproduced by Space Shuttles. In the United States, a Smithsonian Astrophysical Observatory program at the Mount Wilson Observatory in California observed a months-long decrease in atmospheric transparency consistent with an increase in suspended dust particles.

Selected eyewitness reports

Tunguska marshes, around the area where it fell. This photo is from the magazine Around the World, 1931. The original photo was taken between 1927 and 1930 (presumptively no later than 14 September 1930).
Though the region of Siberia in which the explosion occurred was very sparsely populated in 1908, there are accounts of the event from eyewitnesses who were in the surrounding area at the time, and regional newspapers reported the event shortly after it occurred.

According to the testimony of S. Semenov, as recorded by Russian mineralogist Leonid Kulik’s expedition in 1930:

At breakfast time I was sitting by the house at Vanavara Trading Post [approximately 65 kilometres (40 mi) south of the explosion], facing north. […] I suddenly saw that directly to the north, over Onkoul’s Tunguska Road, the sky split in two and fire appeared high and wide over the forest [as Semenov showed, about 50 degrees up—expedition note]. The split in the sky grew larger, and the entire northern side was covered with fire. At that moment I became so hot that I couldn’t bear it as if my shirt was on fire; from the northern side, where the fire was, came strong heat. I wanted to tear off my shirt and throw it down, but then the sky shut closed, and a strong thump sounded, and I was thrown a few metres. I lost my senses for a moment, but then my wife ran out and led me to the house. After that such noise came, as if rocks were falling or cannons were firing, the Earth shook, and when I was on the ground, I pressed my head down, fearing rocks would smash it. When the sky opened up, hot wind raced between the houses, like from cannons, which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn, a part of the iron lock snapped.

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!

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.

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.

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.

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.

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.

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. (per Wikipedia).

First, a Story:

I just took a fire safety course when they asked what steps I would take in case of an explosion…

Apparently, “extremely large ones” wasn’t an acceptable answer…

Second, a Song:

Courtesy of Atlas Obscura and YouTube.com, here is a video of the Tunguska Event.

They state: Atlas Obscura co-founder Dylan talks about the Tunguska Event, one of the largest explosions ever recorded. We hope you enjoy this!

(https://www.youtube.com/watch?v=F7PX51IeMbU)

Thought for the Day:

“Explosions are not comfortable.” – Yevgeny Zamyatin

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Have a great day!

Dave & Colleen

© 2022 David J. Bilinsky and Colleen E. Bilinsky