Imagine an atmospheric explosion so powerful that 800 square miles of trees fall to the ground, pointing outward from a central point. That very thing happened on June 30, 1908, in a very remote area of Siberia called Tunguska. The event is named for the Podkammennaya (Stony) Tunguska River near which the event seems to have originated. The site is northwest of Lake Baikal in extremely rugged terrain.
Very few people dwelt in the Tunguska region when the explosion occurred. A few reindeer herders, hunters, and settlers were the only witnesses to the bright sun-like light with the fiery tail that scorched the sky above them at 7:15 that morning. According to William K. Hartmann’s research, there were camps of reindeer herders about 20 miles from the site who with their tent were blown into the air with the explosion. Many of their reindeer either died or ran away in terror. One reindeer herder who was hurled into a tree by the force of the event received a severely broken arm and died.
When the blast happened, people about 37 miles away were knocked to the ground from the ensuing seismic wave. Many people at short distances from the event lost consciousness for a while with the impact. They felt a tremendous amount of heat surge toward them. Windows were shattered 400 miles away. Some closer storage shacks and campsites were obliterated.
At distances between 110 and 300 miles away, loud bangs were heard after the fiery cloud or ball appeared in the sky and then supposedly struck the earth. Afterwards a dense pillar of dark smoke rose straight up into the air. Atmospheric pressure changes were recorded in London, England, on barographs, new inventions during this time period. Seismic waves were detected 600 miles away and recorded across the continent. European and Western Russian skies glowed in the evening hours for the next few days. Scattered streetlights reflected off microscopic particles in the air, making the evening light bright enough for people to read by.
Twenty years after the event, in 1927, an expedition was sent to collect scientific data on the destruction and any evidence as to the cause. The expedition was led by Leonid Kulik who wished to find out if the event was caused by a meteorite. If the meteorite had left important minerals, especially iron, the Russian government could use them in industry. Kulik, a geologist, had heard accounts of the explosion from residents when he was surveying the region in 1921. No impact crater was found on his 1927 visit. Neither were found remains from any kind of outer space debris.
The expedition did find the epicenter of the blast. The trees closest to the epicenter were stripped of bark and branches but remained standing for about 31 miles. As the expedition moved farther away from the epicenter, the trees were scorched and fallen. Photographs from that time show an eerie pattern of fanned out destruction.
Kulik and others returned three more times between 1927 and 1937 to the Tunguska area on fact-finding expeditions. They drained a small bog to find out if it could be the impact crater for a meteorite that could have caused the event but found instead tree stumps at the bottom. The 1938 aerial photograph of the Tunguska area still did not show an impact crater.
After the United States dropped the atomic bomb on Hiroshima, an event which effectively ended World War II, Russian scientists thought they found similarities between the devastation at Tunguska and at Hiroshima.
In the 1950’s and 1960’s, the Tunguska site was again explored. Very tiny spherical bits which appeared to be like glass were found in the soil. The chemical composition of those microscopic bits indicated large levels of nickel and iridium, elements that are found in other fallen meteorite fragments. The site was tested for elevated radiation levels but none were found.
Today, a little over one hundred years later, scientists are no closer to knowing for certain what caused the Tunguska event and the devastation it left behind.
Resources:
http://www.examiner.com/x-354-SF-Science-Examiner~y2008m6d30-Tunguska-Event-100-years-ago-today
http://www.sandia.gov/news/resources/releases/2007/asteroid.html
http://www.sciencedaily.com/releases/2008/07/080701105330.htm
http://www.psi.edu/projects/siberia/siberia.html
http://www.armageddononline.org/tunguska_asteroid_event.php
