Fire in the sky

On June 30th, 1908 something incredible happened on Earth; specifically, in Siberia, near the Tunguska River. Some witnesses say that it was like the sky was split in two by a huge ball of fire, for others it was like we had another sun. Then they heard a huge thunder, and another, and another. We are talking about the Tunguska event, something that has kept the community of scientists busy for more than a hundred years. The first expedition to the area came after this explosion happened almost ten years later. What they found then was about 80 million trees knocked down in 800 miles square miles. At the center of this area though, the trees were standing, but they were stripped from their branches and bark. Creepy!

So, what’s the theory? Scientists say that it seems to be a meteor or comet that exploded in the air. Even though it didn’t touch the surface of Earth, the explosion had an energy blast a thousand times bigger than the Hiroshima atomic bomb. This kind of impact event (which is the name used by scientists for the collision of comets or other objects with Earth) happens approximately once every ten million years. The next asteroid that could possibly crash with Earth will pass by in the year 2880, so be sure to tell your grandkids to tell their grandkids to tell their grandkids…


For more information about this topic, here are some suggestions:

• The day the sky split apart: investigating a cosmic mystery
  
• Cauldron of hell: Tunguska
  
• Asteroids and meteorites: catastrophic collisions with Earth
  
• Collision Earth! : the threat from outer space : meteorite and comet impacts
  
• Asteroid : earth destroyer or new frontier?
  
• Cosmic collisions: our explosive universe (DVD)
  

There is also a nice article by NASA that talks about this event you might enjoy reading.