Tunguska Fireball - When the Sky ExplodedThe Tunguska Fireball Event was a huge blast near the Tunguska River, the source of which has never been fully explained.
The Tunguska Fireball Event was a huge blast near the Tunguska River, which was estimated to be between 10 and 20 megatons of TNT, 1,000 times more powerful than the bomb dropped on Hiroshima. The source of the explosion has never been fully explained.
The Tunguska Fireball, or explosion, is also known as the Tunguska Event, which occurred on 30th June 1908. This massive explosion happened near Podkamennaya, Tunguska River, in what is now Krasnoyarsk Krai of Russia. The energy of the blast was estimated to be between 10 and 20 megatons of TNT, 1,000 times more powerful than the bomb dropped on Hiroshima, or equivalent to Castle Bravo, the most powerful nuclear bomb ever detonated by the US. It felled an estimated 80 million trees over 830 sq miles. The blast measured 5.0 on the Richter scale.
"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." Siberian Life newspaper, July 27, 1908
The Tunguska event is the largest impact event in recorded history. A modern event over a large metropolitan area would be devastating.
The event's cause is a mystery, although it is widely believed to be caused by the airburst of a large meteoroid or comet about 20m long, 3.6 miles above the Earth's surface.
The Tunguska Fireball Event of 1908
At around 7:15 am, local villagers in the hills northwest of Lake Baikal observed a column of bluish light, nearly as bright as the Sun, moving across the sky. About 10 minutes later, there was a flash and a loud "knocking" sound similar to artillery fire that went in short bursts spaced increasingly wider apart.
Eyewitnesses closer to the explosion reported the sound source moving during each barrage, east to north. The sounds were accompanied by a shock wave that knocked people off their feet and broke windows hundreds of miles away. Most eyewitnesses reported only the sounds and the tremors, and not the sighting of the explosion; to different eyewitnesses, the sequence of events and their overall duration is also different.
A flash fire burned thousands of trees near the impact site, and an atmospheric shock wave circled the Earth twice. For two days afterwards, there was so much fine dust in the atmosphere that newspapers could be read at night by scattered light in the streets of London 6,213 miles away.
For such a large and widespread event, there was little scientific curiosity, possibly owing to the isolation of the Tunguska region. If there were any early expeditions to the site, the records were lost during the subsequent chaotic years, with World War I, the Russian Revolution of 1917, and the Russian Civil War.
There are many other theories about the cause of the blast, which include:
Was Tunguska Fireball a Natural H-bomb?
In 1989, astronomers D'Alessio and Harms suggested that a comet carrying deuterium may have undergone a nuclear fusion reaction while entering the Earth's atmosphere. They concluded that the release of nuclear energy may have been almost negligible. In 1990, Caesar Sirvent indicated that a deuterium comet may have exploded as a natural hydrogen bomb, generating most of the energy released.
Could the Tunguska Event be a Black Hole?
In 1973, physicists at the University of Texas proposed that the Tunguska event was caused by a micro black hole passing through the Earth. Unfortunately, there is no evidence for this hypothesis that a second explosion occurred as the black hole exited the Earth, and this theory has not gained wide acceptance.
Was the Tunguska Event an Antimatter explosion?
In 1965, it was suggested that the Tunguska event was caused by the destruction of a chunk of antimatter falling from space. However, there is no astronomical evidence for such chunks of antimatter in our region of the universe due to the lack of gamma rays.
Did a UFO crash cause the Tunguska Fireball?
It is claimed by UFO enthusiasts that the area was the site of a crashed UFO, possibly shot down by Soviet forces. The lack of investigation between the event and the first expedition in 1921 could be interpreted as a cover-up.
The Tunguska site is downrange from the Baikonur Cosmodrome and has been contaminated repeatedly by Russian space debris, most notably by the failed launch of the fifth Vostok test flight on 22nd December 1960. The payload landed close to the Tunguska impact site, and a team of engineers was dispatched there to recover the capsule and its two canine passengers (who survived).
Scientific Examination of the Tunguska Fireball
In a recent scientific expedition, scientists from the University of Bologna have identified a possible crater left by the blast. The team say that Lake Cheko, although shallow, fits the proportions of a small, bowl-shaped impact crater. Their investigation of the lake bottom's geology reveals a funnel-like shape not seen in neighbouring lakes. In addition, a geophysics survey of the lake bed revealed an unusual feature about 10m down, which could either be compacted lake sediments or a buried fragment of space rock.
We have no positive proof this is an impact crater, but we were able to exclude some other hypotheses, and this led us to our conclusionProfessor Longo, the research team leader.
Intriguingly, Lake Cheko did not appear on any maps before 1929, although researchers admit the region was poorly charted.
The University of Bologna team plans to mount another expedition to the Tunguska region in the summer of 2008 when they aim to drill up to 10m below the lake bed to the anomaly picked up in the geophysics survey and determine whether it is a piece of extraterrestrial rock.
