Happy Tunguska Day to all!

That’s right, today is the 100th anniversary of the Tunguska Event. On June 30, 1908, something exploded over the boreal forests of central Siberia, flattening tens of millions of trees in an area of over 2000 square kilometers. The explosion is estimated to have been the size of 1000 Hiroshima bombs.

What caused this explosion? The most widely accepted hypothesis is that a meteor or comet vaporized in the atmosphere several kilometers above the surface of the Earth. No fragment of this object have ever been found, and other explanations that have been proposed include a natural fusion reaction (due to heating and compression of deuterium in a comet), a black hole going through the Earth, a massive release of natural gas from the Earth, and a UFO crash.

The answer to this mystery is important. An event like this over a populated area could kill millions. If it was caused by a meteor, then we can hopefully identify similar near Earth objects (NEOs) and decide what to do to prevent a disaster. If it were caused by a comet, we have fewer options. Most comets have very long orbital periods, and we would be unlikely to spot the object until it was almost too late. If it were caused by a massive leak of methane from the crust, then we can work at identifying other locations where such things might occur. If it were caused by an exploding antimatter drive on a UFO…

Question: How should we celebrate Tunguska Day? Fireworks? Umbrellas?

Images from the 1927 Soviet Academy of Science expedition to the Tunguska site (from Wikipedia):

Geology.com: The Tunguska Blast

Yahoo/AFP news story: 100 years on, mystery shrouds massive ‘cosmic impact’ in Russia

Grace and Peace