Today marks the 100th anniversay of one of the enduring mysteries of the modern era. On June 30, 1908 an object of some sort exploded above some distance above near the Tunguska River in Siberia. The exact nature of the object remains a mystery but the effects were mind boggling.
For an area of close to 1,000 square miles everything was flattened. Upwards of 80,000,000 trees were destroyed and there was an earth tremor approaching 6 on the Richter scale. The force of the explosion was estimated to be 1,000 times that of the Hiroshima bomb.
Scientists continue to debate whether it was a comet, meteor, black hole or even an exploding UFO. The fact remains though that had the impact occurred in a populated area the death toll would have been huge. Even more ominous, had it occurred today it might have been seen as a nuclear strike and started a war.
Aside from the historical interest, there is a modern day reason to mark this event. According to an article in the NY Times today, scientists know it is just a matter of time before the event happens again.