An Enduring Enigma

One summer night the skies turned so luminescent that people in London could plainly read their newspapers at midnight without artificial lights. Thousands of miles away, Semen Semenov, a farmer in the Krasnoyarsk region of central Siberia saw an enormous fire appearing in the sky, high and wide over the boreal forest, and then a muffled thump came and he was thrown a few yards. There was terrifying loud noise that sounded like cannon thunder and the earth shook. At the same time Russian settlers and Evenki natives in the hills near Lake Baikal observed a colossal pillar of bright bluish light moving across the firmament followed by a flash and the sound of massive artillery fire. In other locations, closer to the mysterious fireball, the shock waves knocked people off their feet. The shock waves also broke windows hundreds of kilometers away from the center of the blast. I have seen old arial photographs of the explosion scene in which the impact-felled trees lying parallel to each other looked like oversized chopsticks, charred or treated with some sort of overboiled bulgogi marinade. The detonation tumbled and flattened the woods. The blown-down trees in the demolished forests turned away from the center of the explosion, lying on the ground en masse, in an eery pattern of profuse symmetry, like vast spokes in a mammoth wheel, with their roots facing the center of the blast. It was 7: 14 a.m., June 30,1908, when Semonov witnessed the raging inferno of what scientists call the Tunguska event. He was about 65 kilometers from ground zero of the gigantic blast whose effects had rippled beyond Siberia, reaching Central Asia as well as Northern Europe. The epicenter of the explosion lay in an uninhabited area of taiga forest where the ground is frozen for most of the year. The blast occurred in the air above the taiga. Scientists analyzed the seismic waves triggered by the Tunguska event and estimate that the energy released by the explosion reached up to 15 megatons in magnitude, which amounts to the magnitude of 1000 Hiroshima atomic bombs combined. On the night of 30 June 1908 and the following three nights aurora glows were observed in northern Europe attributed to the Tunguska event. But what caused this astounding colossal explosion? A group of astronomers, among them Lincoln LaPaz, have suggested that the Tunguska explosion was the result of the annihilation of a piece of antimatter falling onto the Earth from outer space. Others, for example, conspiracy theorist Surendra Verma linked the Tunguska fireball mystery with an early wireless transmission tower designed by Nikola Tesla and built in Shoreham, New York, in 1901-2. Some castle-builders also have claimed that an alien civilization bombed the earth, or that one of the aliens’ nuclear powered ships attempted to land in Siberia but exploded over the boreal forest without touching ground. The list of explanations also includes an astrophysical theory, according to which a miniature black hole penetrated the Earth’s atmosphere and exploded. However, the scientific consensus relegates the Tunguska event to the wanderings of space debris. Asteroids, comets and meteoroids are plentiful in the solar system and it seems that one of these spece debris not only ventured not only very close to the Earth but actually penetrated its atmosphere and blew up above the taiga just before hitting the ground. It is estimated that this stray space debris weighed around a million tons and was 100 to 200 meters in diameter. At any event, the puzzling incident of the Tunguska blast remains an enduring enigma.