very fascinating, especially given the knowledge that a comet will intersect earth at some point in the future.  perhaps this will not occur in our lifetime, but certainly within a few hundred years.

the event, known as the tunguska event or tunguska explosion, was a powerful mysterious explosion in 1908 that occurred near the tunguska river in what is now krasnoyarsk krai in russia. although the cause of the explosion is the subject of debate to this date, it is commonly believed to have been caused by the air burst of a large meteoroid or comet fragment at an altitude of 5–10 kilometers above the earth’s surface. the explosion registered on seismic stations across eurasia. in some places, the shock wave would have been equivalent to an earthquake of 5.0 on the richter scale. what’s more, is that it produced fluctuations in atmospheric pressure strong enough to be detected in great britain. more recent discoveries here. by dd