June 30 marks the 104th anniversary of the Tunguska Impact. This event was not well recognized at first. It happened in a remote location; 1908 was a time of political unrest in Russia; and the seismic activity from the event could have come from a number of sources.
The origin, track and outcome of the explosion that took place in the early morning on June 30 are still under debate by scientists.
Some have concluded that it was a near earth asteroid that came really near. A group of Italian scientists proposethat Lake Cheko in western Siberia might be a crater formed when a chunk of debris broke off the cosmic object and created a trench that then became the lake. The most often discussed possibility is that a comet, or piece of a comet, entered earth’s atmosphere and exploded before impact.
According to an eye witness who was questioned by an investigative team,
Suddenly in the north sky… the sky was split in two, and high above the forest the whole northern part of the sky appeared covered with fire… At that moment there was a bang in the sky and a mighty crash… The crash was followed by a noise like stones falling from the sky, or of guns firing. The earth trembled.
Most dramatic are the photographs of trees that were burned and blasted away from the impact, losing their branches and looking list the results of a clear cut on the most massive scale.
Tunguska remains a mystery and a talking point among scientists and lay people to this day,
“If you want to start a conversation with anyone in the asteroid business all you have to say is Tunguska,” says Don Yeomans, manager of the Near-Earth Object Office at NASA’s Jet Propulsion Laboratory. “It is the only entry of a large meteoroid we have in the modern era with first-hand accounts.”
References:
Gunsmoke and Knitting 