The nature of this spectacular event has been a delicious puzzle for most of my life, one of the best of my personal X files. I remember the feeling of awe when I first learned about it as a kid; a mighty explosion without any apparent cause was both impressive and spooky. What did this to Siberia? Why couldn’t we find any evidence? Could it be aliens? (I wondered that about almost anything unexplained for the first half of my life!) Tunguska was one of the things that sparked my interest in astronomy, which turned into a lifelong hobby (though I haven’t done much with a telescope since moving to Vancouver).
Of course, for a long time, the Tunguska “mystery” has really just been “comet or not?” — a good puzzle, but not so exotic. And, holy crap, now we finally know: not. The reason there was no evidence of the meteor for so long was that it was blown to microscopic smithereens. It just took a bunch of decades and some modern methods to find them.
For nice icing on the story cake, the Tunguska impact was of pretty much exactly the same type as the Chelyabinsk meteor earlier this year … just way, way bigger.