Moscow, Russia (RIA Novosti) Jul 24, 2009
More than 100 years have passed since the Tunguska Meteorite Event and the mystery of its occurrence remains unsolved, but scientists have not given up on solving the riddle. This July, an international research group from Italy and the United States ventured into deepest Siberia to investigate the most likely explanations of the mysterious event, and RIA Novosti correspondent David Burghardt joined them.
On June 30, 1908, Eastern Siberia was hit by an explosion equal to 2,000 times the nuclear bomb that destroyed the Japanese city of Hiroshima in 1945, destroying 2,200 square kilometers of taiga and flattening tens of millions of trees. If this impact had occurred four hours later, the city of St. Petersburg and other nearby villages would have been wiped off the face of the earth.
Travel to epicenter
It was not until the winter of 1927-1928 that the first expedition was organized to investigate reports from witnesses of the event. The expedition was led by Russian scientist Leonid Kulik, who headed for the epicenter in search for the meteorite he believed was the only possible explanation for the event.
Travel back then to such a remote area was a very expensive and grueling affair, taking first a train to Krasnoyarsk in Eastern Siberia, and then traveling north on foot for hundreds of kilometers. Kulik's first expedition 19 years after the event enlisted numerous native Evenki guides and dozens of reindeer. Kulik, like hundreds of scientists after him, found no traces of a meteorite.
Travel to the area today is much easier than in Kulik's time, taking an airplane from Moscow to Krasnoyarsk, then a small prop plane to the village of Vanavara, and finally a Russian Mi-8 cargo helicopter into the region of the epicenter.
The two-week expedition included six professors from the University of Bologna, the University of Florence, and Cornell University.
There are some 100 theories of the Tunguska Event, including some of the more bizarre ones of a UFO crash site, a WWII bomber caught in a time warp and returning to 1908, Earth crossing through a black hole, and a cloud of mosquitoes that spontaneously combusted due to heat created by flying too densely.
The first theory was created in 1908 by native Evenki tribes in Eastern Siberia who were the actual witnesses of the event. According to their legend, the fire god, Agdy, became angered and destroyed all that was living in the area. Witnesses said there were several deafening explosions and trees were heard falling thousands of miles away.
The researchers looked at two of the most probable theories: meteorite impact and volcanic gas vent explosion. The scientific expedition was divided into two camps, one at Lake Cheko, where they were researching the meteorite theory, and the other at Kulik's Cabin near the epicenter (some 10 kilometers from the first group), where they were researching geological explanations for the blast.
METEORITE IMPACT THEORY (Lake Cheko)
Four professors from the University of Bologna, Carlo Stanghellini, Maurizio Serrazanetti, Romano Serra, and Marco Cocchi, believe Lake Cheko was created by a meteorite impact due to its shape and tree growth in the area. The lake is elliptical (approximately 100 meters by 300 meters) rather than round, which is consistent with other lakes and swamps in the area.
However, no impact ring or rim residue has been discovered at the lake, which would be noticeable had a meteorite created the lake. The native Evenki say that the lake has always been there and the name comes from the Evenki language meaning "dark waters."
Professors Stanghellini and Serrazanetti focused their research on the lake bottom using both technical and not so technical equipment, including a magnetometer, radar, underwater camera and grappling hooks.
The scientists used a magnetometer to locate magnetic elements on the floor of the lake such as iron or other metallic elements, which would indicate that a meteorite or its fragments were on the bottom. Stanghellini described a magnetometer as a sophisticated compass that will show peaks on a monitor if it finds something metal.
He said that just like a regular compass, if you set a piece of metal near it, the arrow will point to the metal piece and not to the magnetic North. Because of the magnetometer's sensitivity, the scientists did their research on an inflatable rubber raft using wooden oars so as not spike the instrument. Before the process, they flagged
the entire lake in 10-meter swaths. They discovered a small anomaly in the center of the lake on one of the passes and said they would study the data more thoroughly on their return to Italy. On the following day, however, the magnetic anomaly was not detected on the screen and the scientists did not collect any other substantial evidence to support their theory that there are meteorite fragments on the bottom of the lake.
They also conducted radar soundings and underwater filming, but again came up with no substantial evidence.
Grappling hooks were dragged along the lake bottom to recover debris. They recovered mostly small branches and roots, which may or may not have been from 1908. The scientists said that the debris could have been under a thick layer of silt that would have preserved the debris, though they may have been recently deposited by the stream flowing into the lake. These samples were packed and sent to the university to define their age and find any proof of impact damage to them.
Stanghellini said further research of the lake's bottom was necessary, especially in drilling a core sample beneath the lake, though this would require international support and financing.
On shore, professors Serra and Cocchi cut down several trees and collected slabs as well as core samples of trees that survived the 1908 event, trees that were destroyed after the event and younger trees that appeared after the event. Samples were taken on the North and South side of Lake Cheko.
According to their preliminary studies, the samples showed that the trees had tight rings prior to the 1908 event, which means the trees grew very slowly due to competition with other trees and were growing densely together. Serra said that in 1908, the trees show scars with resin deposits (pitch) and then a very slow growth rate for two years due to shock. After 1910, the trees show much wider rings, which indicate there was less competition with other trees, more sunlight and nutrients.
He also said that the coniferous trees in the area should be associated with trees from the taiga and not lakeside forests, where there is usually heavy underbrush. Serra said that tree samples taken 4-50 meters from the lake are similar in growth patters of trees 2-3 kilometers away from the lake prior to 1908, indicating that all of the trees are native to a taiga environment and not a lake.
He added that a significant growth change occurred in the trees located by the lake after 1908; whereas, those trees kilometers away from the lake continued to have tight rings due to slow growth and competition.
Serra noted that the survivor trees were much smaller during the 1908 event, meaning that they were bent over or twisted during the impact. All of the large trees, on the other hand, were uprooted. He said this is similar to what happens to trees during a hurricane. He also noted that the tree samples taken near Lake Cheko were similar to those taken after the Chernobyl nuclear reactor meltdown site in Ukraine in 1986.
Evidence collected in previous expeditions by Serra showed that tree limbs from 1908 contained deposits of magnesium, titanium, sulfurs, and several undefined elements, which would support the theories of a meteorite or even volcanic activity.
All four of the Italian researchers at Lake Cheko believe the lake was created by one of three impacts in 1908: the first exploded in the atmosphere, the second struck the ground, creating Lake Cheko and changing the direction of the creek, and the third struck the ground further North at the epicenter, presumably creating several deep bogs. They agreed that the meteorite that created the lake would have been 1-5 meters in diameter and the tree growth around the lake proved that it was created in 1908.
Cocchi did much research on an old creek bed that the scientists assume was cut off or rerouted after the 1908 event. Difficulties in researching the creek bed arise due to the fact that 20 centimeters under the surface there is permafrost that cannot be dug up. Drilling the creek bed is also planned to get a core sample in order to estimate when the creek changed its course and began flowing into the lake after it was created by the meteorite, according to the scientists.
VOLCANIC GAS VENT EXPLOSION THEORY (Tunguska Epicenter)
According to Morgan, this rock was actually "burped up" when the gas vent exploded, pushing the rock to the surface through a funnel. Morgan named the still unconfirmed funnel after his colleague, Paola's Funnel. He noted that this rock is the only one of its kind in the area and is definitely of volcanic nature. The scientists collected some 30 kilograms of rock samples, especially quartz and quartzite, from and around John's Rock, in search of shocked quartz, which would indicate that there was volcanic activity in the area.
Vanucchi said that some of the rock samples showed traces of being shocked, or fractured, and further research on the samples would be completed in both Italy and the United States. She also said that they believe they have found the main vent of the volcanic gas explosion very near to John's Rock.
The researchers revealed that the Russian geological mineral map they were supplied with was incorrect in many places in regard to the elements found in the area, as well as to the depth of some of the quartz deposits. Vanucchi said that they had started updating the existing map, but further research would be needed to perfect it.
The scientists were also interested in Churgym Waterfall which showed one of the largest samples of volcanic basalt in the world, indicating millions of years of volcanic activity in the area. There was a constant flow of lava, which is visible in layers around the falls and stream. Only some 30 meters of the basalt is above the surface, which is visible due to erosion by the stream and there is no estimate of how deep the volcanic rock extends beneath the earth.
Morgan said the amount of basalt in the area is so great that it proves the existence of constant volcanic activity for millions of years. Samples from the waterfall area were also taken for comparison with those from the John's Rock location. Though lava has ceased to reach the surface, lava vents still exist and can build up pressure and blow, thus creating a blast like that in the epicenter.
Vitaly Romeiko, the director of the Department of Astrophysics at Zvenigorod Observatory, said in an interview in Moscow that the 1908 event was caused by a fragment of the Encke Comet's tail that entered the Earth's atmosphere as a ball of ice with small interplanetary fragments (dust particles) and, upon entrance, exploded due to the negative ions in the comet and the positive ions found on Earth. He pointed out that the Encke Comet also revolves around the sun and comes near Earth every 3.3 years.
Romeiko has participated in 23 expeditions into the Tunguska region.
Olga Gladysheva, a senior fellow at the A.F. Ioffe Physics and Technical Institute in St. Petersburg, supported Romeiko's theory in a separate interview with RIA Novosti, adding that the part of the comet's tail separated and created a giant ice ball that was created in a vacuum, and, therefore, made several explosions as the particles inside expanded and the ball disintegrated.
The Russian scientists base their theory on the fact on the absence of any meteorite material in the area, no rock fragments, or no impact areas that would create a crater.
Gladysheva said part of the comet's tail entered the Earth's ionosphere at more than 80 kilometers above ground, which is an intense area of atmospheric electricity. She said a major blast occurred over the epicenter at an altitude of 7-10 kilometers above the Earth's surface. The significance of the blast was due to the overly charged ions and differences in the positive and negative poles in the comet and Earth.
Romeiko said the ice ball that formed around the comet's dust particles before striking Earth would explain the absence of a crater or meteorite particles. The particles from the comet would be very minute and could most likely be found in the lower layers of peat moss in the area, which is frozen in permafrost.
101 YEARS OF AN UNSOLVED MYSTERY
Although the researchers returned without any substantial explanations for the event, they plan on returning to Tunguska to continue their research and prove their theories. Serra said there would be interest in the Tunguska Event far into the future, because the best scientists from around the world have been there and no one has come up with an explanation, which scientists simply cannot accept.
When the Italian and American research group left the epicenter, a new group of Russian "scientists" arrived. One of the group members said that she had worked with a psychic to identify which swamp a UFO had collided into in 1908.
Upon returning to the town of Vanavara, some 65 kilometers to the South of the epicenter, the Tunguska Reserve director, Ludmila Logunova, said that they know where the meteorite is located, but if they reveal its location, people would stop visiting the region.
Source: RIA Novosti
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