The Tunguska Event was a major explosion of nearly 12 Megaton near the Podkamennaya Tunguska river in Russia. It occurred on June 30, 1908.
It was a massive explosion that vanished millions of trees in just a few seconds. It was believed that the Tunguska blast also knocked people down to death.
The region was the Eastern Siberian forest where there is snow all the time. The event is regarded as an asteroid burst. An asteroid entered the atmosphere 50 meters in size and exploded near the ground.
The asteroid did not reach the ground, and therefore there is no impact crater in that area even after this event was caused. When a scientific expedition was conducted, it was analyzed that the explosion was so big that it could destroy an entire city.
It is so famous now, that any related event occurs anywhere, that’s compared to the Tunguska event.
1. Eyewitness Reports
The Tunguska event was witnessed by people many miles away from the event site. The place is northwest of lake Baikal. People remember that there was a bluish light stretching in the sky.
Suddenly, an explosion occurred, and huge shock waves accompanied the sound. People closer to the site fled away and the houses were abandoned. It was like another Hiroshima for them.
The explosion was also felt by people not only in that region. But, in the Eurasian region and Western Europe like Germany, Denmark, and Scandinavian countries. The light was aglow for several days due to reflection from the ice caps.
On the Richter scale, it was shown as equivalent to a 5.0 magnitude of Earthquake. Scientists in the USA analyzed that the Earth’s atmosphere was not clear due to dust particle pollution.
1.1. S. Semenov
He remembered the night of June 30, sitting in his house when he saw a bright light in the sky, and fire appeared high over the forest area. The whole event was in the northern direction.
He said although he was 65km away from the Tunguska region, the heat was so intense that he felt, he was on fire. But suddenly, the sky shut closed and a strong sound came with a forceful wave, throwing him a few meters away.
It was like the earth shook and stones would fall from the sky. Many crops were damaged, and windows shattered.
1.2. Chuchan
He belonged to a local tribe. He and his brother was sleeping in his hut when they heard a loud sound like thumping on the ground. He got scared because of the falling trees, and the earth was shaking.
They wanted to rush outside the hut, but the thunder again struck. The light was so bright that he described it as a second sun. Trees were fired up. Everything was very scary.
According to Chuchan, 2-3 thunder sounds occurred in a short period. But according to the reports, only one sound was heard by the locals.
2. Newspaper Reports
Newspapers covered the Tunguska incident by assuming different theories. Some said that it was a heavenly body, an alien spacecraft, or simply just an explosion.
2.1. Sibir Newspaper
They reported that a blueish heavenly body, with a pipe-like structure, appeared in the northwest direction. The body turned into a very bright light when it approached the ground.
Black smoke was all over the place, according to the local peasants. Buildings were shivering due to the shock wave it created. People, especially women, and children came out of houses, escaping house collapses.
The newspaper described it as a doomsday and the end of the world.
2.2. Siberian Newspaper
It was a complete meteorite event that sent waves all over the direction of an earthquake on the ground.
They also compared the Tunguska event with a large artillery calibre firing, like a military event.
2.3. Krasnoyaretz newspaper
It described the event as a horrific event that was followed by an earthquake. A large rock hit the ground at a very high speed shaking the ground.
They took the Tunguska event in a series of events. The thumping of the ground was followed by an earthquake. And after some intervals, the region was under artillery fire.
The sky was clear initially but, it became very bright after some time, making it like the sun descending from the sky to the earth.
3. Scientific Expeditions of the Tunguska Explosion
Due to political upheaval in the Russian empire at that time, it was difficult to conduct a scientific expedition.
However, after a decade after the event, some Russian scientists took permission from the Russian Government to study the mysterious explosion.
3.1. Leonid Kulik’s Expedition
In 1927, a Russian scientist, Leonid Kulik, hired some local hunters to guide them to the site and began the first scientific expedition. According to the eyewitness accounts, it created a strong thump sound event that occurred on June 30, 1908.
Kulik and others were expecting an impact crater at the site because of the description of such noise. But there was no crater found.
Instead of a crater, they found an 8 km region where trees were devoid of branches but standing upright.
Following the expedition, he also found various potholes on the site, which he described as meteorite holes but later on, after careful analysis, they turned out natural holes.
3.2. Surveys
Various survey teams in the 1950s and 60s era went to the explosion site and found silica, nickel, and magnetite in trees, rock samples, and soil.
These minerals are indicators of meteorite fragments as meteorites contain these minerals in large quantities.
Various aerial photographs were also captured in the form of positive and negative samples. But the negative films were destroyed by the Soviet academy due to their flammable nature.
Furthermore, analysis of peat bogs present at the site revealed the chemical composition. There were traces of isotopic carbon, nitrogen, and hydrogen in deep layers which were not present outside of that area.
At the time of this event, there was a limited number of equipment that could be used for scientific analysis. An iron meteorite caused the Tunguska event, at least, that was accepted. However, there were different theories propounded by scientists.
3.3. Comet Impact Theory
Scientists believed that the absence of traces of the Tunguska body is evidence that the Tunguska meteorite was a comet.
Comet is a cosmic body made up of ice. When they enter the earth’s atmosphere, ice evaporates rapidly, leaving no traces behind. This was a possibility that the comet evaporated completely as it reached the ground.
3.3.1. FJW Whipple
FJW Whipple, a British meteorologist claimed that the Tunguska event was caused by a comet. A tail in the sky with leftover dust and ice particles is the evidence that confirms this.
3.3.2. Lubor Kresak
A Slovak scientist and astronomer, he suggested that the comet was Jupiter’s Comet Encke which is responsible for the meteor showers every year.
The Tunguska explosion was an event caused by a fragment of this comet. This claim was supported by several scientific phenomena.
The Tunguska incident occurred when the activity of meteor showers was at its peak. It was also analyzed by satellite observations that comets reaching near the ground, explode 10 to 100 kilometers above ground.
3.3.3. Zdenek Sekanina
He challenged the comet hypothesis by claiming that the body’s shallow trajectory showed that a comet does not behave in that way. When a comet reaches the earth, it does not remain intact, as happened in this case.
He also suggested that the Tunguska object had an asteroidal origin. Probably it came from the asteroid belt.
3.3.4. Ferinella and Foschini
In 2001, the findings of Zdenek Sekanina were supported by these two scientists. They were sure that it is around 83% probability that the body came from the asteroid belt according to its trajectory readings.
However, the main contention related to the asteroid hypothesis is that it did not create an impact crater at the site. It is mostly seen that an asteroid, when struck to the ground, makes a big crater.
3.3.5. Christopher Chyba
He created a model in which he was able to show a similar event. He proposed that when a body reaches the earth’s atmosphere, the forces to disintegrate it becomes more potent than those that hold it together.
These forces blow the body part with all of its energy released at once without taking any crater.
3.3.6. Utyuzhnikov and Rudenko
They created a 3D model in 2008 which confirmed the comet hypothesis. According to the model, huge shock waves were released during the Tunguska event, and the comet exploded in the atmosphere.
3.3.7. Giuseppe Longo
He tried to extract some materials from the felled trees and remains of the Tunguska event to learn about the chemical and physical properties.
He and other physicists concluded that the materials were close to an asteroid rather than a comet.
3.3.8. Edward Drobyshevski
He is a Russian scientist, who suggested that the Tunguska body was part of a giant asteroid. Just before the Tunguska explosion, there was a close encounter of an asteroid 2005 NB56 with the Earth’s atmosphere.
The orbit of the parent body matched the trajectory of the suspected body of Tunguska.
American scientists further confirmed the chemical composition of the body of an iron meteorite.
3.4. Chelyabinsk Bolide Event
A meteorite entered the Earth’s atmosphere into the Ural region of Russia in 2013. It was a massive meteorite that started fragmenting in the upper atmosphere to the ground.
Researchers drew a comparison between this event with the Tunguska explosion. Various models were created.
Some were tested by creating similar circumstances. If the Chelyabinsk event was caused by the same kind of incident with similar explosive power what could be the impact?
Researchers also analyzed the radial pattern of fallen trees and atmospheric consequences to having a wider perspective on such objects.
3.4.1. Statistics
It was concluded that the closest to the suspected body is a stony asteroid of diameter between 50 to 80 m that entered the atmosphere at almost 55000 km/h of speed.
The energy released at the Tunguska site was equivalent to the volcanic eruption of Mount St. Helens which was recorded at 10 to 30 megatons.
3.5. Earth Impact Model
The closest explanation to the Tunguska event is the meteorite explosion to date. Scientists from around the world have a consensus that there was a huge explosion due to an unknown body.
Many concluded that a meteorite struck the earth’s surface. Generally, meteorites enter the atmosphere at a speed of 10-11 km/s and generate immense heat and a blast wave.
Due to this heat, these stony bodies explode mid-air, before even reaching the ground. This burst produces massive energy on the scale of 10 to 30 megatons, similar to a nuclear detonation.
Scientific estimates suggest that the size of the Tunguska meteorite was around 65m in diameter.
Since the 20th century, scientists have been observing the earth. Events like asteroid impacts are common and now and then, the earth experiences asteroid air burst.
However, the impact and size of these events are very small. Bodies like the Tunguska meteor enters the atmosphere once every 1000 years according to recent estimates.
Modern scientific equipment has only captured one such event. It was the Chelyabinsk meteor which was a 500-kiloton body and shattered windows.
3.6. Computer Models
Recently, some Russian researchers created computer models taking asteroids of 50m, 100m, and 200m in diameter, entering the atmosphere at a speed of 11 km/s.
The results that matched closely with the Tunguska impact were with the 200m diameter model. This opened up various possibilities.
If the model was accurate, a 200m meteor cannot vanish in such a region, making the Tunguska mystery a headache for the scientific community.
3.7. Tunguska Blast Patterns
The Soviet Union scientists made model forests in the 1960s revealed that the blast waves made in the models were butterfly shaped similar to the Tunguska region massive explosion.
The object made a 30 Degree angle while falling. It made an angle of 115 degrees with the northern side.
3.8. Lake Cheko
Some scientists found a lake in the same area, approximately 8km from the actual site of the explosion. It was believed that this lake is a result of the crater made by the meteor.
Although it was not disputed that there was a sky split and a meteor exploded near the earth’s surface. But a small fragment got separated from the meteor and created this crater.
Others refute this claim by adding that the lake existed even before the event. Even the age analysis of the silt deposited at the bottom of the lake is 5000 years old.
3.8.1. Recent Findings
Recent publishings suggest that the sediment cores of the lake were checked when studied carefully, it was revealed that the above layer is just 100-odd years old. It gives some support to the crater hypothesis.
Acoustic and magnetic readings reveal that the shape and depth of the lake are consistent with the crater hypothesis. There can be some rock fragments of the meteor below the silt deposit which strengthens scientific theories.
- The core is 175 cm long and present near the center, consisting of a 1 m thick layer of lacustrine deposits.
- Remains of Aquatic plants in the core are in abundance in the post-impact event as compared to the pre-event.
- Traces of organic Nitrogen, Hydrogen, and Oxygen suggest that the crater was created by a cosmic body.
- Both, free-floated plants and rooted plants were found in the lake check. But when we go into depth, there is evidence of hydrophytes, suggesting an absence of a lake before the explosion.
However, a 2017 study by some Russian researchers claims that the age of the soil present in the lake is older than 280 years. Therefore, refuting the crater hypothesis theory.
Some traces of radionuclide contamination are also found due to a nuclear test. This helped scientists to analyze the average depth of the soil layer.
3.9. Geophysical Theories
Astrophysicist Wolfgang Kundt negates the idea of an atmospheric explosion. He claims that the event was caused due to release of around 10 million tonnes of natural gas from within the earth.
When it was released, the gas lifted upwards due to its temperature. It was ignited by atmospheric lighting. This ignition fired up the place reaching the source of the gas on the surface and therefore turning into an explosion.
4. Frequently Asked Questions (FAQs)
4.1. Where Is This Region Located?
The event was caused near the Podkamennaya Tunguska river region, Russia. The whole place has Taiga forests which fall in the Eastern Siberian area. There is hills northwest of the region.
4.2. What Are Asteroids?
Asteroids are rocks present in our solar system which are remains of the planets. These are present in the asteroid belt of the solar system.
Due to gravitational forces, these asteroids come out of this belt. Earth also experiences the entry of asteroids into its atmosphere. Most of the time, they burn in the air but sometimes they reach the ground.
4.3. How an Asteroid Is Different from A Meteor?
Asteroids are those which revolve around the sun but when they enter the atmosphere of the earth and burn, they are called meteors.
4.4. Differentiate Between a Comet and A Meteor
Comets are ice and dust balls that revolve around the sun. They are commonly found beyond the outer planets. They can be seen with a long tail, which is nothing but evaporating water. Whereas, meteors are rocky materials and do not project tails.
4.5. What Is an Impact Crater?
When an astronomical object struck the ground, it forms a depression circularly. It depends on the force of the impact which causes the ground to turn into a depression.
4.6. Define Sky Split
The sky splits occur naturally. When clouds or objects like meteors put a barrier in the sunlight to reach the earth, the sky seems to be divided into two. Due to this two different colors or combination of the sky is visible.
4.7. What Is a Shock Wave?
These are vibrations that are generated when the ground is struck by a huge object or by an earthquake-like event. In the Tunguska impact case, a probable meteor struck the ground which generated huge waves.
These waves can destroy public property, damage trees, and also bring cracks in the ground.
4.8. What Is an Air Burst in The Context of Meteors?
When meteors enter the atmosphere, huge frictional forces are working on them. Due to these forces, meteors burn like a fireball. This generates so much heat that they burn up in the air itself.
However, sometimes due to heat, instead of burning up, they explode in the air near earth which is called an air burst.
4.9. What Is a Sediment Core?
When we analyze the soil and go into its depths, we find various layers of soil. These layers consist of various minerals and compositions. This whole sample of the layer of the soil is called the sediment core.
4.10. What Is a Radial Pattern?
Radial patterns are impressions created circularly. In case of meteor strikes, certain impressions are created on the ground which is spaced and angled properly. These are called radial patterns.
4.11. What Is a Scientific Expedition?
This is a kind of survey done by scientists based on scientific rules. When an event like the Tunguska blast happens, scientists investigate the area and collect evidence.
In the case of the Tunguska event, the first scientific expedition was led by a Russian mineralogist Leonid Kulik from the Soviet Academy of Sciences.
Conclusion
The Tunguska event has become one of the mysteries of the 20th century. The huge blowing up of the body has led the scientific community to ponder upon mysteries of nature that are not easily solvable.
Several scientists have proposed their theories about the event. But none of them has concluded. The most accepted theory was the comet hypothesis theory which explains the bursting of a comet near the earth’s surface.
When similar incidents are analyzed like the Chelyabinsk event of 2013, the same kind of signatures was left on the ground. This indicates that the June 30 incident of the Tunguska river had some relation to a meteor or comet bursting.
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