Tunguska

In the early morning of 17th June 1908 something exploded over the remote forested wilderness of Tunguska in Siberia– laying waste to over 80 million trees and devastating an area of more than 2000 square kilometres. The multi-megaton blast was one of the largest explosions known to man – hundreds of miles away from the blast, windows were broken and people were lifted off their feet.

Yet, no one can be sure what caused it.

Because of the remoteness and the political situation in Russia at the time, the first scientific expedition didn’t reach the area until 1921. What they found were scenes of utter devastation – inexplicable in those times before nuclear energy.

The initial assumption was that the explosion was caused by a meteorite strike but when the epicentre was located, scientists found no evidence for a meteorite impact.

Puzzled by the absence of a crater, people have sought other explanations for the Tunguska event. There have been suggestions that it was an exploding UFO but one of the strongest theories is that the huge explosion was caused by a comet. The idea here is that a comet accelerating towards the earth will meet increasing air resistance as is passes through the atmosphere. The resulting forces will be more than capable of causing the comet’s nucleus to break up, potentially leading to a huge explosion and fireball – just like that witnessed over Tunguska.

Whatever the explanation, it was fortunate that the incident happened over thinly populated areas of Siberia. If the 1908 impact had been even an hour or so later, when the earth had turned a few degrees on its axis, the explosion could well have happened over an urban area, causing utter destruction and leading to thousands or perhaps even hundreds of thousands of deaths.