A meteor explosion in the atmosphere still seems the most likely cause for the 1908 disaster that flattened a forest in Siberia — and a new analysis of rock fragments appears to support that conclusion. Grains from Siberian peat bog now suggest to be remnants of the biggest Earth impact in recorded history.
They came from outer space. Fragments of rock retrieved from a remote corner of Siberia could help to settle an enduring mystery: the cause of the Tunguska explosion.
On 30 June 1908, a powerful blast ripped open the sky near the Podkamennaya Tunguska river in Russia and flattened more than 2,000 square kilometres of forest. Eyewitnesses described a large object tearing through the atmosphere and exploding before reaching the ground, sending a wave of intense heat racing across the countryside.
At an estimated 3 to 5 megatonnes of TNT equivalent, it was the biggest impact event in recorded history. By comparison, the meteor that struck the Russian region of Chelyabinsk earlier this year 'merely' packed 460 kilotonnes of TNT equivalent.