100 years ago today, a small chunk of rock or possibly ice was lazily making its way across the inner solar system when a large, blue-green planet got in its way. Traveling roughly westward, it entered the Earth’s atmosphere moving at tens of thousands kilometers per hour. Compressed and battered by tremendous forces, the object got about 5 – 10 kilometers from the ground before it succumbed, exploding like a gigantic multi-megaton bomb.
The air blast flattened trees for hundreds of square kilometers. The ground shook, witnesses felt the hellish heat from kilometers away, and the shock wave circled the world. It happened over the remote Podkammenaya Tungus river, a swampy region in Russia; had it happened over Moscow a million people might have died within minutes.
Now known as the Tunguska Event, it stands today as a shocking reminder that we live in a cosmic shooting gallery, and the Earth sits in the crosshairs of many objects.
I’m not too worried about impacts from outer space objects. Hopefully we’d see it coming, and if there’s anything we could do about it, we would (one hopes). My concern is what would happen if something like Tunguska happened today and it wasn’t terribly destructive, because it would probably be followed shortly by someone’s nuclear arsenal, and then there would be terrible destruction. Overreaction, I’m sayin’. Imagine, if you will, that today was the 50th anniversary of Tunguska, not the 100th. That would mean that, on June 30, 1958, a massive fireball of uncertain origin erupted over Siberia. We know now that the Soviets didn’t have as much atomic annihilation capacity as was once feared (although it was and is pretty f–in’ scary), but they also had a highly flawed decision-making structure. It would at least make for some interesting alternate history.