Today is the anniversary of what is known as the Tunguska Event. It is named for the Tunguska river in a very remote area of Siberia. On June 30th 1908, it was the site of a massive explosion. The blast destroyed 830 square miles (2,150 sq km) of forest. It is the largest such event in recorded history and, even now, no one can really agree on what caused it. Luckily it was such a sparsely populated area that no fatalities were reported, and hopefully this is because there weren’t any.
Because it happened in such an isolated place, and because Russia was facing a period of extreme political upheaval at the time, no one visited the area to investigate the cause until 1921. There are a few eyewitness reports of the event. This is what a man named Semyon Borisovich Semyonov had to say when he was interviewed in 1930:
“…the sky split in two and fire appeared high and wide over the forest. 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.”
Among those who witnessed the event, a few said they had seen an object in the sky, To some it was a red fiery ball, to others it seemed to be shaped like a tube and was blue or white in colour. Many agreed that it was too bright to look at. Most people just heard it and described a noise like thunder, or like artillery fire, or falling rocks. The tremors were recorded all over the world. For three days afterwards, glowing clouds were seen in the night sky, so bright that it was possible to read a newspaper, all over Northern Europe. The name for clouds that glow in a dark sky is ‘Noctilucent Clouds’, which is lovely. Here is a picture of some…
The explosion is thought to have been caused either by an exploding meteorite or a comet. Leonid Kulik, the first man to investigate the site, expected to find a huge crater in the middle of the area of devastation, but what he found was a clump of trees that were stripped bare but still standing. For miles around the trees had been knocked down in a direction away from the blast. It seems that what ever caused it had exploded in the air, stripping the trees directly below it, with the force radiating outwards when it hit the ground.
Some mineral samples taken in the area suggest a meteorite, but it is far from conclusive. The lack of any obvious impact sites and the reports of glowing clouds suggest a comet. The glow could have been caused by fragments of dust and ice from the comet in the upper atmosphere catching the sun’s rays. I did find an eyewitness report that claimed a new lake had been formed in the explosion, and that it boiled for two days. But this seems to have been dismissed. However, there is a lake nearby called Lake Cheko which may or may not have been created by a fragment of meteorite. A team of investigators from the University of Bologna believe they have identified a large rock, deep in the lake which may be a piece of the meteorite. They also have evidence from the sediment in the lake that it may be only a hundred years old, but because the area is far from any centre of population, nobody can be certain how long it’s been there.
There are many other explanations on offer. Some suggest that a cloud of natural gas, from under the earth’s crust, may have been forced to the surface and then been ignited by lightening. Others that it was caused by a scientist called Nikola Tesla, who claimed to have invented, and therefore perhaps tested, a weapon that could transmit electricity through the air. Among some of the even crazier theories are a black hole colliding with the earth, an exploding spaceship and a nuclear bomb that somehow travelled back in time and exploded over Siberia. What ever happened, we are incredibly lucky that it did not explode over a major city. St Petersburg, Helsinki, Stockholm and Oslo are all on the same latitude, and could easily have been in the path of a comet, meteorite, spaceship or time-travelling bomb.