At dawn on a summer day 103 years ago on the banks of the river Podkamennaya Tunguska, Siberia. The first rays of sun warmed the pine forest wild and wet ponds, when the sky exploded and the ground felt its fury.
Tunguska Explosion 30 July 1908
Around 7:15 that morning June 30, 1908 a shock wave about a thousand times stronger than the Hiroshima bomb devastated 80 million trees over 2,000 square kilometers of forest. Reindeer, bears, wolves, foxes and thousands of other animals fell along with the vegetation the area never fully recovered himself.
The Tunguska explosion was the biggest impact that Earth suffered throughout the history of civilized man. Similar events, even in ancient times, remained unknown until the advent of satellites.Although the epicenter was deserted, people in hundreds of places in Asia and Europe witnessed the incident. The stories were remarkable. Strong heat waves, intense winds, horrific crashes and earthquakes were reported. Many saw a ball of fire and its tail in rushing smoky horizon.The night sky was glowing for weeks, as the amount of dust released into the stratosphere by the blast. In London, more than 10,000 km, one could read a newspaper at night, with only this light. Across the ocean, the Smithsonian American Observatory recorded a decrease in atmospheric transparency that lasted for months.
Spectacular eventWhat happened? Of course there was much curiosity as much as lay scientists. But the first expedition to examine the region left more than a decade later, in 1921. On occasion, the Soviet geologist Leonid Kulik failed to achieve the exact location, and deduced that the event was due to fall of a large meteorite.
This hypothesis eventually persuaded the Soviet government to fund another expedition in 1927, attracted by the possibility of finding a meteorite iron of commercial value. But no crater was found, much less a meteorite. Other expeditions have confirmed this lack.
It was calculated that the magnitude of the blast was between 10 and 15 million tons of dynamite. But the object that caused it has not touched the ground, smashing into the air, about 8 km high.
Until now the most intense event similar happened in 1930 on the river Corucia, Amazonas, reaching a maximum energy of one million tons of dynamite.
Rejected the assumption of a meteorite, but taking into account the reports of the fireball, a hypothesis emerged even more spectacular - and most likely: in 1908, a piece of comet collided with Earth.
Tunguska / Тунгуска
Comet or asteroid?
A comet is made mostly of ice. Ice water and a little methane and ammonia. Upon entering Earth's atmosphere a small comet is usually evaporates before touching the ground, yet could produce a bright fireball and a powerful shock wave and heat, to raze the surface without leaving an impact crater. The only traces in the soil were very small diamonds and tiny spheres of glass (silica), with high concentrations of iridium and nickel, which would prove the extraterrestrial origin. Tunguska expeditions sent in 1950 found just such evidence.
Much more recently, in 2007, Mark Boslough and his group at Sandia National Laboratories first used supercomputers to simulate in three dimensions the Tunguska event. The strategy resulted in an entirely new framework. And scary.
Before, it was assumed that a piece of comet the size of a football field, weighing a million tons and moving at 108,000 km / h would have caused the explosion. However, the simulations suggest that a small asteroid would have the same effect.
The projectile would be increasingly compressed by the increasing resistance of Earth's atmosphere, to the point where they explode in the air, producing a violent flow of heated gas that would continue the path to the ground. The estimates now range from 3 to 5 million tons of dynamite enough energy to cause the shock wave of Tunguska.
The study of the Sandia lab enhances our understanding of the mechanism of explosion, but he warns. The number of potentially hazardous asteroids is much larger than that of comets. Whatever it is, the possibility to happen again requires the preparation of a good defense strategy. Because the Earth's rotation, if the collision had occurred in Tunguska about 4 ½ hours later, the city of St. Petersburg, former capital of the Russian empire, would have been wiped out forever.
For 100 years the world population has hovered around 1 ½ billion people. Today we are almost 7 billion, occupying more space, especially in coastal areas. The destructive potential of a new Tunguska is incalculably greater. Worse still occur over the sea. And the question is not whether it will happen again, but when.
The so-called natural "H-bomb" theory
Could exotic material in a comet have initiated a natural thermo-nuclear chain reaction in the Earth's atmosphere leading to the Tunguska Event?
Two scientists, Serge J.D. D'Alessio and Archie A. Harms thought it possible in 1989. They theorized that a comet may have been carrying the element deuterium a component of nuclear fusion. The interaction with the atmosphere could have created a kinetic release of energy triggering a natural hydrogen bomb detonation. In 1990, Csar Sirvent, a nuclear physicist came to the same idea independent of D'Alessio and Harms.
However, subsequent studies have found no evidence of any radioactive isotopes in the blast area. The probabilities of a nuclear explosion are statistically zero.
The black hole theory
The idea of black holes has been kicked around since the late 1960s, but it wasn't until 1973 that two physicist, Albert A. Jackson and Michael P. Ryan from the University of Texas, postulated that the explosion might have been triggered by a microscopic black hole tunneling through the Earth. The weakness in this hypothesis is that no seismic activity was detected in the North Atlantic where the black hole would have emerged. Nor would it account for the dust trails in the upper atmosphere that were recorded after the explosion.
The proposed theory of antimatter particles
Back in 1941 an explanation for the explosion was hazarded by Lincoln Paz that involved the interaction of anti-matter particles with Earth. Fourteen years later during 1965 three other scientists, Chandra Atluri, Clyde Cowan and Willard Libby picked up the thread from Paz and postulated that anti-matter was the cause behind the event. The hypotheses is flawed, however, as no evidence exists that is what occurred. Furthermore, if events of this nature have occurred, astronomical evidence should be rife throughout our galaxy. Anti- matter/matter collisions would result in annihilation and produce a constant stream of gamma rays.
The theory of an alien spaceship crash
Called by some UFO theorists "The Russian Roswell," referring to the alleged saucer crash in Roswell, New Mexico during July, 1949, claims have been made that extra-terrestrial spacecraft debris has been secretly recovered from the blast area.
They claim that a UFO blew up over the Siberian forest in 1908.
Earlier this year, in March of 2009, the president of a dubious organization called the "Tunguska Spatial Phenomenon Foundation" reiterated all the claims made about an alien spacecraft being the cause of the explosion.
Dr. Yuri Labvin claimed that alien quartz slabs inscribed with a strange language had been retrieved at the epicenter of the blast site.
He further insisted that these slabs were all that were left of the main control panel of the UFO.
While these otherworldly conspiracy theories do nothing to advance the serious investigation of the Tunguska Event, they are creative and mildly amusing.
The Tesla connection
Without a doubt, the most fascinating theory to emerge in the great debate over the Tunguska Event is the contention the explosion was caused by Nikola Tesla, in other words it was man-made.
This controversial theory has been promoted during the past several years by Oliver Nichelson and others.
Nikola Tesla (1856 - 1943) is perhaps the greatest overlooked genius in American history. His inventions are legion and his investigations into the nature of electricity and magnetism are still finding applications today.
Among his many accomplishments, Tesla developed the technology that enabled television to become a reality; he enabled Edison's power plants to transmit electricity 1000 times farther than Edison's method; and he built and tested radio long before Marconi.
In one of those flukes of history, Tesla - a perfectionist - finally brought his radio transceiver (far superior to Marconi's rudimentary device) to the U.S. Patent Office two days after Marconi's application. The patent, of course, was awarded to Marconi.
Among Tesla's many inventions was broadcast power. His devices enabled machinery to run without being plugged in to an electrical grid. In his world, the entire Earth was an electrical grid.
While his broadcast power experiments made world news, his greatest project - one that later led to his infamous death ray experiments - was the broadcast tower in Colorado Springs. That tower was the precursor to his Wardenclyffe Tower project in Shoreham, Long Island, New York that was never fully completed.
In a letter to the New York Times dated April 1908 Tesla expanded upon his idea of destruction by electrical beams. He wrote, "When I spoke of future warfare I meant that it should be conducted by direct application of electrical waves without the use of aerial engines or other implements of destruction." Then he went on to add, "This is not a dream. Even now wireless power plants could be constructed by which any region of the globe might be rendered uninhabitable without subjecting the population of other parts to serious danger or inconvenience."
Tesla knew what he was talking about. He had constructed such towers and seen first-hand what they could do. They were capable of generating great destructive power arriving at the speed of light anywhere...
Read the rest of Terrence's article on Helium.com: History mystery: Tunguska explosion of 1908 - helium.com