The June 30, 1908 near the Tunguska River in Siberia Podkamennaja there was a huge explosion that destroyed millions of trees over an area of 2150 square kilometers. The explosion was so strong that it was felt up to 1,000 kilometers away.
The cause of the explosion has never been clear, the affected area was completely uninhabited. Only in 1927, almost twenty years later, was organized the first expedition, led by Russian scientist L. Kulik.
To explain the explosion have been advanced over the years various assumptions, the most accepted is that the impact of a meteorite of a few tens of meters in diameter.
In recent days, has been published in the Geophysical Research Letters (published by the American Geophysical Union) an article entitled Two-dimensional turbulence, space shuttle plume transport in the thermosphere, and a possible relation to the Great Siberian Impact Event, by some Researchers at Cornell University, where it is assumed that the Tunguska explosion was caused by a comet.
The article takes into account the clouds that are formed after the launch of the Space Shuttle, clouds were seen after the launch of the Space Shuttle Endeavour (STS-118) launched on August 8, 2007, which were also observed for other launches the Space Shuttle in 1997 and 2003. These clouds consist of water ice, are particularly bright, are formed at a high altitude in the mesosphere and are known as noctilucent clouds .
In the days following the explosion of Tunguska were observed in Europe and particularly in Britain for several days this type of clouds.
Every single shuttle flight produces 300 tons of water vapor that are released into the thermosphere , from this water vapor will form noctilucent clouds in the mesosphere .
Article connect the two events, the launch of the Shuttle and the fall of the comet assuming that the exhaust of the Shuttle has had the same effect as falling comet that released water vapor in the atmosphere. Water vapor produced noctilucent clouds seen in the days following the explosion of Tunguska.