On June 30, 1908, at 7:17 A.M. local time, the largest explosion in history occurred in the forests of Siberia.
Though the explosion occurred in 1908, the scene was not investigated until 1930, when Soviet scientists trekked to the North of Siberia. What they found was a vast scene of cognitive dissonance.
Though the explosion had obviously been unimaginable -- the yield is today estimated at 5-30 megatons (!) and remember, nobody would see even a low-yield atomic bomb for 15 more years -- the scene was full of anomalies.
These are the indisputed facts of the catastrophe:
1. The blast force was in the vicinity of 15 megatons. It was the largest impact event in recorded history, including from modern nuclear testing. 2. There was no trace of any impact crater. 3. Trees at ground zero were stipped of bark -- but still standing. 4. Sampling of plants, water, and earth yielded few clues or residual matter; the clues that resulted tended to be inconsistent with the theory of a large impact. 5. Around 80,000,000 trees from 3 to 10 miles away from ground zero were knocked over, their tops falling away from ground zero. The total area of scorched trees was about 30 miles in diameter. 6. The resulting earthquake would have registered about 5.0, if the Richter scale had been devised at the time.Here is an account of the explosion, attested by S. Semenov who was 40 miles south of ground zero (footnote 1):
"At breakfast time I was sitting by the house at Vanavara trading post, facing North. [...] I suddenly saw that directly to the North, over Onkoul's Tunguska road, the sky split in two and fire appeared high and wide over the forest. The split in the sky grew larger, and the entire Northern side was covered with fire. At that moment I became so hot that I couldn't bear it, as if my shirt was on fire; from the northern side, where the fire was, came strong heat. I wanted to tear off my shirt and throw it down, but then the sky shut closed, and a strong thump sounded, and I was thrown a few yards. I lost my senses for a moment, but then my wife ran out and led me to the house. After that such noise came, as if rocks were falling or cannons were firing, the earth shook, and when I was on the ground, I pressed my head down, fearing rocks would smash it. When the sky opened up, hot wind raced between the houses, like from cannons, which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn a part of the iron lock snapped."Speculation on the cause is an industry both in printed books and on the internet: UFO explosion? "I need more power, Scotty!" "I kinna hold 'er togetha inny longa, Keptin!" UFO buffs often view alternative explanations as cover-ups. Just for fun, we might note that although it's hard to imagine anything happening to stress a UFO "warp coil" :- ) once it's gotten to earth after a long journey ... still, simple malfunctions could be attributed. Black hole collides with earth? Accounts such as "the sky split" and the multiple waves of energy have sparked the speculations revolving around sci-fi applications of laws of physics. Albert A. Jackson and Michael P. Ryan, credentialed physicists at the University of Texas, maintained that a black hole passed through the earth. The questions here would be, where was the exit event, and where are the cataclysmic effects to the earth's mantle? Speculations have included theories revolving around antimatter falling to earth. However, there is no evidence for the existence of "chunks of antimatter" in the Milky Way galaxy. Russia explodes an H-bomb four decades early? If you are interested in the general field of anachronisms, this explanation might interest you. But it is hard to imagine Stalin's Soviet Union not exploiting such technology in, say, 1940. As well, the entire Soviet research industry of the 1920's and 1930's becomes nothing but a vast, flawless coverup. ............... The scientific consensus is that a "lightweight" (low-density) asteroid exploded about 5 miles above the forest. The asteroid may have been composed of space debris and ice, and when the ice melted in the atmosphere, the explosion occurred. The asteroid therefore would not have hit the ground, though the shock wave would have. The hypothetical speed of the asteroid is placed at around 7 miles a second. The shock wave was easily equivalent to that of 2,000 Hiroshima bombs; if the asteroid had arrived 4 hours and 47 minutes later, all of St. Petersburg would have been destroyed, every human being killed for at least 10 miles in any direction. Opponents of this theory, of course, point out aspects of the evidence that are not consistent with this understanding. ............. Slight alterations of the trajectory or timing -- if the Tunguska explosion be due to an asteroid -- would have wiped out London, Rome, or Munich, in nature's equivalent of a (mega-) nuclear strike. As it was, not a single human life was lost. The Earth caught a very, very big break in 1908. ................... Astronomers tell us that if Jupiter weren't serving as a "shield" for Earth, then the Earth would suffer 1,000 times more asteroid hits than it does. The craters on the surface of the moon are sobering. None of us worry much about asteroids. An odd serendipity that Earth's citizens live their lives free of fear from asteroids. Cheers, jemanji ......... (1) N. V. Vasiliev, A. F. Kovalevsky, S. A. Razin, L. E. Epiktetova (1981). Eyewitness accounts of Tunguska (Crash)., Section 6, Item 4 bottom image: http://www.psi.edu/hartmann/pic-cat/images/488_Tunguska-A_Minute_After_E... (artist's rendition, of course)
