On June 30, 1908 something exploded over the central Siberian forest near Stony Tunguska River in Russia. Countless herds of reindeer were incinerated and several rustic villages vanished from the face of the Earth. The concussion was so powerful its ferocity would not be approached for another 37 years, when the atom bomb was detonated over Hiroshima, Japan. Yet even the 'Fat Man" atom bomb dropped on Nagasaki was 1,000 times less powerful that the Tunguska Event. In fact, the most powerful nuclear weapon ever detonated - the Soviet Union's "Tsar Bomba" barely equaled one-third of the energy released over Siberia that June day 101 years ago.
The destruction was frightening. If whatever it was had released its explosive force over Moscow or St. Petersburg instead of a lonely, sparsely inhabited rural region of the country, those major cities would have been obliterated.
More than 500,000 acres of pine forest - 80 million trees - were splintered and overturned in an area roughly covering 830 square miles. The concussive shock wave rolling across the countryside shattered windows 100 miles away was heard over a radius of 620 miles and registered as an earthquake on worldwide detectors. All this and it never even touched the ground.
Evidence painstakingly gathered by investigators over the decades indicates an airborne explosion occurred that had remarkable similarities to a modern-day thermonuclear blast.
Eugene Shoemaker, the astronomer that discovered the comet Shoemaker-Levy that plunged into Jupiter's atmosphere, has estimated that events such as the Tunguska explosion occur about once every three centuries.
Theories abound explaining the how and whys of the Tunguska Event, yet none have been definitely proven as the penultimate answer.
Mainstream theories on what caused the explosion
[1] A catastrophic meteoroid air burst
Could a large meteor or small asteroid have caused the explosion over Siberia? That was the theory bantered about for many decades after the incident. It dominated for decades and still has many supporters. Yet the primary problem with the meteor/asteroid theory is that no incontrovertible meteorite residue or particles have ever been found other than tiny spheroids that may have been meteoric in origin.
A Russian expedition undertaken during 1927 found no evidence of meteoric material. No impact crater was discovered. The scientific team that included geologists drilled almost 120 feet down but no pieces of meteoric material was found.
[2] An icy comet explosion
Could the Tunguska Event have been caused by the explosion of a small comet or cometary debris in our atmosphere? That hypothesis was put forward in 1930 by the British astronomer F.J.W. Whipple. He believed that a comet, composed mainly of small rocky material and ice impacted the Earth's atmosphere, exploded with concussive force, and left no trace.
This hypothesis seemed to be supported by reports throughout Europe in the days following the Siberian blast of brightly glowing night skies. The glowing night skies can be explained by huge quantities of dust and ice generated by a comet exploding and reflecting ambient light.
Building on Whipple's original hypothesis, astronomer ubor Kresk argued in 1978 that the Tunguska explosion was caused by a fragment of Comet Encke. Then, in 1983 astronomer Zdenk Sekanina argued against the comet hypothesis. He proved that the Tunguska objects trajectory was so shallow that long before it could have exploded above the Siberian forest it would have vaporized in the upper atmosphere; therefore it could only have been a small asteroid. Later evidence bolstered Sekanina's contention that the object had to have been an asteroid when it was determined that the Tunguska object had its origins in the asteroid belt.
[3] A geophysical, catastrophic methane release
In January 2004, an astrophysicist at Bonn University named Wolfgang Kundt threw a new hypothesis into the debate. "If a group of experts cannot agree for almost a hundred years, it's probably a third option," said Kundt.
The "Earth and Planetary Science Letters" published Kundt's article, "Contemporaneous mass extinctions, continental flood basalts, and 'impact signals': are mantle plume-induced lithospheric gas explosions the causal link?" in their January 2004 issue.
Basically this German physicist believes that the explosion was precipitated by more than ten million tons of methane gas. This gas, he argues, was released from deep within the Earth's crust. Such a massive release of explosive gas would be biblical in its destructive capability. "Evidence of a similar apocalyptic release can be found on the Blake Ridge on the seabed off Norway, a pockmark of 280 square miles," Kundt stated.
Exotic theories
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 on the Earth.
Several theorists have proposed that Tesla was testing his wireless power generator during June of 1908. They point to some interesting facts to support their case. According to one, "Historical facts point to the possibility that this event was caused by a test firing of Tesla's energy weapon."
He draws this conclusion based on the fact that Tesla wrote at length about the powerfully destructive ability of his new energy transmitter. Based on the designs of the prototype that Tesla had built and tested in Colorado Springs, his Wardenclyffe complex and primary energy tower were a quantum leap beyond his original transmitter in Colorado.
Tesla's tireless effort to improve upon his generation of wireless energy continued to mount during 1900 to 1910. According to some historical students of Tesla's life they contend the brilliant inventor had reached a desperate crossroads in his life: facing mounting financial woes and at loggerheads with orthodox scientists, Tesla fell into a deep depression and suffered a nervous breakdown. Some theorize that in a dramatic bid to resurrect his formerly brilliant career, the inventor might have tested his giant transmitter to demonstrate its massive destructive ability.
The year most likely for that demonstration to have occurred was during 1908.
Years later, during 1915 Tesla wrote: "It is perfectly practical to transmit electrical energy without wires and produce destructive effects at a distance. I have already constructed a wireless transmitter which makes this possible. [But] when unavoidable [it] may be used to destroy property and life. The art is already so far developed that the great destructive effects can be produced at any point on the globe, defined beforehand with great accuracy."
When Tesla wrote that in 1915 he seems to have made an admission of a test of the Tower. Although undocumented, Tesla did have the capability to transmit high energy wave frequencies generating catastrophic forces in excess of 10 megatons.
Directed wireless power transmitted through the globe and erupting with raw fury from the surface somewhere else is perfectly consistent with the evidence of the aftermath of the Tunguska Event and - more importantly - it was supported by the eyewitness accounts of the catastrophe.
What then was experienced by the witnesses to the event?
Accounts gathered by the Russian mineralogist Leonid Kulik, in his 1930 expedition to the site of the explosion are consistent enough on many details to be considered generally reliable. Most recalled a bluish-white cylinder of light in the sky followed by a series of concussive reports like thunder. A few reported the ground trembling as if dozens of freight trains ran underneath the ground. The significance of that is they felt the rumbling vibration coming from beneath the ground before the explosion.
These reports could all support a multi-billion watt energy pulse emerging from the ground as a bluish-white light of such intensity it outshone the sun. It was cylindrical in appearance and caused a series of thunderous reports such as lightning strikes create during violent electrical storms.
The Russian newspaper Krasnoyaretz reported on July 13, 1908 just two weeks after the event:
"Kezhemskoe village: An unusual atmospheric event was observed. At 7:43 a.m. the noise akin to a strong wind was heard. Immediately afterwards a horrific thump sounded followed by an earthquake that literally shook the buildings as if they were hit by a large log or a heavy rock. The first thump was followed by a second and then a third. Then the interval between the first and the third thumps were accompanied by an unusual underground rattle, similar to a railway upon which dozens of trains are travelling at the same time. Afterwards for 5 to 6 minutes an exact likeness of artillery fire was heard: 50 to 60 salvoes [sic] in short, equal intervals, which got progressively weaker. After 1.5 - 2 minutes after one of the "barrages" six more thumps were heard, like cannon firing, but individual, loud and accompanied by tremors.
"The sky, at the first sight, appeared to be clear. There was no wind and no clouds. However upon closer inspection to the north, i.e. where most of the thumps were heard, a kind of an ashen cloud was seen near the horizon which kept getting smaller and more transparent and possibly by around 2-3 p.m. completely disappeared."
Other first-hand accounts from eyewitnesses corroborate the evidence investigators discovered when sifting through the debris of the Event's aftermath. Many described a darkened cloud that gradually flattened into a dish or saucer-shaped form. The cloud was pierced by an intense beam or shaft of light.
Testimony of witnesses: Kirensk, a farmer - "[I saw]a fiery pillar in the form of a spear"; Nizhne Karelinsk, a chicken breeder - "[It] turned into a fiery pillar and disappeared in a moment"; Another unnamed farmhand - "A forked tongue of flame broke through the cloud"; from a man identified only as Vanavera interviewed by the Krasnoyarsk newspaper -"A huge flame shot up and cut the sky in two."
There's something else that's odd that does not lend itself to supporting the popular theories of meteoric, asteroid or cometary airborne explosion. The day of the Tunguska Event the Irkutsk Observatory recorded magnetic anomalies that left a signature resembling those that are made by atomic blasts. The detection of the magnetic disturbances began about six minutes after the initial explosion over Siberia and continued for more than four hours. The blast signatures that the observatory recorded are almost identical to those recorded decades later that nuclear air bursts generate.
Many scientists have argued that if the Tunguska Event was caused by a meteor, asteroid or comet those signatures could not have been produced. It is recognized that some large meteors passing through the Earth's ionosphere have caused minor magnetic disruptions, none compares to the four hour plus magnetic disturbance generated by the Tunguska explosion.
No professional or amateur astronomers anywhere on Earth reported a fireball. A gigantic booming sound was heard with multiple reports diminishing in intensity afterwards; no debris fell from the sky. No impact crater has ever been found which is reasonable if an energy beam erupted upwards from beneath the ground. Yet, magnetic and electrical disturbances were reported for several days over Europe. The sky glowed like twilight all night long. Massive glowing "silvery clouds" were reported over northern and northeastern Russia.
All of this is consistent with significant electrical disturbances of the atmosphere which Tesla's massive Wardenclyffe Tower was quite capable of achieving.
Tesla claimed that his wireless transmitter achieved experimental power levels into the tens of billions of watts. That power, released within a time frame compressed to microseconds could easily have achieved the destructive energy of a multi-megaton explosion. As some have speculated, what Tesla had created was a diabolical device capable of transmitting the destructive power of hydrogen bombs. As he later suggested through his letters and newspaper interviews any location anywhere on the planet could be annihilated at the speed of light and with the mere flick of a switch.
Could any of this actually be true? Was Tesla exaggerating the power of the Tower or was he under the veil of a self-delusional fantasy?
Recently, a team of electrical engineers conducted a wide-ranging analysis of Tesla's wireless transmission technology. His machine did not propagate radio waves as we understand them today. Instead, the Tower - and the prototype in Colorado Springs - transmitted electrostatic energy waves. Those waves could easily pass through the Earth. Little power would be loss during the pulse transmissions.
Did he power up and "fire off" a transmission towards Russia? According to some researchers, circumstantial evidence discovered amongst Tesla's notes, the chronology of his work and his financial upheavals point to the strong possibility that he did fire the wireless energy from the Tower at full power at least once and maybe on several other occasions at lower power levels.
The evidence, while not incontrovertible, does point towards the possibility that Tesla tested his wireless energy generator. If he did, the test would have occurred sometime around the middle of 1908. A likely target could have been the sparsely populated Polar Regions. Tunguska sits on the southernmost edge of the Arctic Circle.
So what caused the Tunguska Event - a meteor, asteroid, comet, methane gas explosion . . . or Nikola Tesla's Wardenclyffe Tower project? Each hypothesis has evidence for and against them.
Did Nikola Tesla shake the world 101 years ago? That question still awaits an answer.
Photos
Trees knocked over by the Tunguska blast.
Photo of Tunguska Event damage
Siberian forest in the aftermath of the Tunguska Event
Links
"The Tunguska Phenomenon"
"The Tunguska Explosion"
Astrobiological evidence
A Tesla - Tunguska connection?
Photo of Nikola Tesla
Another of Tesla
The famous Tesla Tower erected in Shoreham, Long Island, New York was 187 feet high; the spherical top was 68 feet in diameter. Nikola Tesla constructed the tower for his "World Wireless" energy project.
Artist representation of Wardenclyffe Tower
Oliver Nicholsen (PDF) - "Tesla's Wireless Power Transmitter and the Tunguska Explosion of 1908"
The Tesla Society
Other links and notes:
Scientific American - "The Tunguska Mystery 100 Years Later"
interScience, Terra Nova - "A possible impact crater for the 1908 Tunguska Event"
BBC - "Team makes Tunguska crater claim"
National Geographic - "Crater from 1908 Russian Space Impact Found, Team Says"
Popular Mechanics - "When Comets Attack: Solving the Mystery of the Biggest Natural Explosion in Modern History"
Fox News - "Massive Tunguska Blast Still Unsolved 100 Years Later"
Associated Press - "100 years on, mystery shrouds massive 'cosmic impact' in Russia"