Surendra Verma, science writer and author of 'The Tunguska Fireball'
Surendra - On 30th June 1908, an enormous explosion took place in the remote Tunguska region of Siberia. In 1927, a Russian scientist was assigned the task of investigating meteorite falls in Siberia. So he went to Siberia and he talked to people who were there. From their accounts, he pin-pointed the location of the explosion site. He saw a whole plateau, bigger than Greater London, where the forest had been flattened, all the trees stripped of their leaves and branches, and he also noticed that there were traces of intense fire, that had extended some tens of kilometres in diameter.
Chris - Well that sounds terrible. Was he actually sure that it was definitely a meteorite though?
Surendra - He went there four times and he started looking for the crater formed by the meteorite and fragments of the meteorite in the crater. In spite of all those searches, he could never find any craters or fragments.
Chris - Have we got any clues as to what it really was caused by, or do scientists think that it presently was a massive meteorite?
Surendra - We know a lot more about the Tunguska Fireball actually. Most of the scientists will bet that it was an asteroid impact. Scientists have done a lot of computer simulations, and they think that the size of the asteroid was about 30 metres across; so small that it didn't leave any hole in the ground. The explosion caused all the damage to the forest. So on the scientists side we have asteroid theories and we have comet theories. But on the other side we have that Tunguska was mistakenly zapped by a laser beam sent by extra terrestrials on a planet eleven light years away from Earth.
Chris - That's some greeting card isn't it, to decimate an area the size of Greater London! There must be friendlier ways to send an intergalactic message.
Surendra - Yes, but that's my interpretation of the theory. That's how I put it together.