Imagine, that you’re in central Siberia near the Stony Tunguska river a little over a hundred years ago. You’re hanging out at a small trading post when all of a sudden the northern sky splits into two and catches fire. You are thrown to the ground as an explosion equivalent to 15 megatons of TNT going off bursts into being, glass from the surrounding buildings crashing down around you. Twenty miles closer to the blast entire reindeer herds are destroyed as their herders are blown high into the air.
The resulting seismic shockwave registers on instruments as far away as England. People in Asia report being able to read their newspapers outdoors under the glowing night sky. Nineteen years later when a team of scientists finally arrives at the site (it is in the middle of Siberia, after all) they find eight hundred square miles of forest that had been torn from the ground. But more surprising were the trees that stand at the site of the explosion, standing upright but with their limbs and bark stripped away.
Years later the same effect would be observed at a site of another huge explosion: Hiroshima, Japan.
The Tunguska event, as it is called, is often bandied about as evidence of whatever conspiracy theory is currently making the rounds. What could possibly have caused such a huge explosion in 1908? Why wasn’t there an impact crater? Some claim that it was the result of a nuclear-powered UFO crash or alien attack, others that it was caused by a miniature black hole or by a chunk of antimatter falling to earth. But one of the most popular theories is that it was caused by one Nikola Tesla.
Tesla is an interesting figure in history. An eccentric genius, his work was instrumental in ushering in the modern electrical age. Yet he was maligned and ostracized during his life, partially because of his bizarre and outlandish claims. One of his unusual experiments was the Wardenclyffe Tower, where he held that he would be able to transmit electrical energy without wires and even “produce destructive effects at a distance.”
While history holds that the tower was never finished due to lack of funds, theorist claim that Tesla saw Robert Peary’s second attempt to reach the North Pole as a chance to prove his worth to the world. He had notified the expedition, asking them to report the details of anything unusual they might witness on their journey. Then, on the evening of June 30th, he aimed the tower’s “death ray” towards a spot roughly west of the Peary expedition.
The device emitted a dim light and an owl that flew into the path of the beam disintegrated instantly. Nothing else happened and the device was turned off. Tesla was ready to admit failure when he heard of the Tunguska explosion and, realizing the true havoc his invention had caused and the danger it posed to the world, he dismantled it.
Ignoring the scientific evidence for or against a “death ray” of this kind, it’s hard to determine whether Tesla actually played any part in this story at all. Guaranteed he, along with the rest of the world, was following Peary’s expedition; proof of that lies in an article he wrote in 1905 congratulating Peary on receiving funding and suggesting that in the future such a laborious means of travel shouldn’t be necessary. But despite repeated assertions in conspiracy literature that Tesla contacted Peary before he left for his expedition, or even that he tried to contact him during, I have been unable to come across any evidence that such communication did occur.
Not to mention that Tesla was not known for keeping his discoveries to himself. Had he indeed been responsible for the event at Tunguska, why wouldn’t he announce that fact to the world? Even if he was overcome by the damage he had caused it still would have effectively proven that what he had always theorized was possible: he could send large amounts of energy wirelessly.
In fact, Tesla did announce that he had recently discovered something along the lines of a particle beam capable of attack at long distances. In a letter to J.P. Morgan, Jr., he announces that “I have made recent discoveries of inestimable value…” that could protect London from incoming enemy planes.” The problem? He didn’t write this letter until 1934, nearly three decades after Tunguska.
One more interesting tidbit about the Tesla story, although it seems a bit nitpicky, is that the Tunguska event took place at approximately 7 am on June 30th local Tunguska time, which would have been about 7 pm on June 29th for Tesla. This means that even if we believe the account to be true, Tesla’s test actually took place after the Tunguska explosion.
But with no primary eyewitness accounts of the Wardenclyffe test itself, and without any acknowledgment on Tesla’s part of such a test, the truth of the matter is that the story was probably manufactured after the fact. Someone noticed that Peary was exploring the arctic at the same time as the explosion and realized that they could draw a rough line between Tesla’s Wardenclyffe tower, the arctic, and Tunguska and embellished the story from there. Tesla’s interest in the expedition likely only provided further fuel for the fire.
But if Tesla wasn’t responsible for the Tunguska event, what was?
Scientists now believe that it was caused by large object entering the Earth’s atmosphere (whether it was a comet, asteroid or meteorite is still debated to this da7). Looking at historical eyewitness accounts of the fiery skies and clouds that lasted days later, researcher Michael Kelly from Cornell University noted the similarity to the noctilucent clouds that have been observed appearing days after various space shuttle launches. It is theorized that these brilliant, night-visible clouds are made up of ice particles and can appear when massive amounts of water vapor are spewed into the upper-atmosphere. Something like the space shuttle’s exhaust plume can cause such an effect or, in an earlier time, the breakup of an icy body high above the earth.
Such a breakup, likely the cause of a combination of pressure and heat as the space rock entered the Earth’s atmosphere travelling at about 33,500 miles per hour, would have produced a fireball and released a huge amount of energy. It would also explain why there is no impact crater, as the majority of the body would have been consumed in the explosion.
Later expeditions to the site did find microscopic silicate and magnetite sphere in the soil and felled trees. Chemical analysis of the findings revealed proportions similar to those found in meteorites, and the concentration of the spheres was found to be consistent with the expected distribution of debris from a meteorite airburst.
The interesting thing about Tunguska is that if this was indeed the result of a comet or asteroid entering our atmosphere, the damage was nowhere near as bad as it could have been. Imagine if the trajectory had been different and the explosion had happened over the Netherlands or Moscow. Or even if it had actually impacted with the ground? The situation becomes even more frightening when we consider that studies reveal that such explosions may happen every couple of centuries. All it takes is a stony meteoroid of about 10 meters in diameter to match the damage created by the Little Boy atomic bomb that destroyed Hiroshima.
This is partially why NASA has pledged to discover at least 90% of all the Near-Earth Objects (NEOs) whose diameters are larger than a kilometer within the next 10 years. Groups like the Linear Asteroid Detection Project, the Loneos Program, the Catalina Sky Survey and the Spacewatch Program are helping NASA to reach that goal.
This way, when the next Tunguska happens, we might be better prepared, rather than just making up theories after the fact.