In 1908, a comet or asteroid struck Tunguska, Siberia with so much force that it destroyed more than 2,000km of terrain. The celestial body exploded 5–10 km above ground, releasing 10–15 Mton of energy. Or did it? Some of the kookier among us believe that the explosion’s cause wasn’t an asteroid impact, but one of Tesla’s experiments gone wrong. The fact that to date, no one has discovered a fragment of the Tunguska impact body fuels the fire for these folks:
“Tesla said his transmitter could produce 100 million volts of pressure and currents up to 1000 amperes, with experimental power levels of billion or tens of billions of watts. If that amount of power were released in “an incomparably small interval of time,” the energy would be equal to the explosion of millions of tons of TNT, that is, a multi-megaton explosion. Such a transmitter would be capable of projecting the force of a nuclear warhead by radio. Any location in the world could be vaporized at the speed of light.” (taken from Frank Germano athttp://www.frank.germano.com/tunguska.htm )
Back on June 30, 1908 when the devastating impact occurred in central Siberia, one of the closest eyewitnesses, local farmer Semen Semenov saw “the sky split in two. Fire appeared high and wide over the forest…. From … where the fire was, came strong heat…. Then the sky shut closed, and a strong thump sounded, and I was thrown a few yards…. After that such noise came, as if . . . cannons were firing, the earth shook …”
The effects of the blast were felt as far away as Northern Europe and Central Asia. Today, scientists are still puzzled over what exactly caused the impact and blast; finding out could be central to our understanding of the evolution of the Earth. The impact of a Mars-sized planetoid 4.4 billion years ago was responsible for creating the Moon, and thanks only to the gradual accretion of planetary materials and the movement of those materials into stable orbits over time, we’ve been spared another planet-sized impact. Our atmosphere helps to burn up many other potentially dangerous meteorites, but asteroids still have the potential to devastate our planet.
Luckily, researchers have determined that it’s unlikely another celestial body that large could smack into Earth in our lifetimes. Researchers at the University of Western Ontario and Los Alamos National Laboratory use satellite observations of meteoric “flares” in the atmosphere, better known as shooting stars, to collect data on cosmic impacts on Earth. They use this information to estimate the rate of impact of smaller objects, and extrapolate that information to understand the likelihood of larger, Tunguska-like events. They found the likelihood of such events occurring to be on the order of 1 in 200 years to 1 in 1,000 years.
And, since Tesla is no longer around to conduct a wireless experiment gone wrong, we can all breathe a sigh of relief, for now.