109 years ago today, there was a large explosion over a remote part of Siberia known as Tunguska, the result of what many think was an asteroid or comet that blew up in the Earth’s atmosphere. The explosion has been estimated to be 185 times more powerful than the atomic bomb dropped on Hiroshima in the second world war; trees were flattened upto 50 km from the blast centre, but no impact crater was found.
The BBC has a nice summary in an article published last year of what happened, in non-technical language.
