UNSOLVED MYSTERY: 1908 Tunguska Event 185 x More Powerful Than Hiroshima Atom Bomb…On 30 June 1908, an explosion ripped through the air above a remote forest in Siberia, near the Podkamennaya Tunguska river. The massive explosion packed a wallop. The resulting seismic shockwave registered with sensitive barometers as far away as England. Dense clouds formed over the region at high altitudes which reflected sunlight from beyond the horizon. Night skies glowed, and reports came in that a person who lived as far away as Asia could read newspapers outdoors as late as midnight. Locally, hundreds of reindeer, the livelihood of local herders, were killed, but there was no direct evidence that any person perished in the blast.
But when it hit it hit with tremendous force. One account noted that jus after seven in the morning, a man sitting on the front porch of a trading post at Vanavara in Siberia was hurled from his chair and the heat will be so intense he will feel as though his shirt is on fire. That’s how the Tunguska event felt 40 miles from ground zero.
Fortunately, the area in which this massive explosion occurred was sparsely inhabited. There were no official reports of human casualties, though one local deer herder reportedly died after he was thrust into a tree from the blast. Hundreds of reindeer were also reduced to charred carcasses.
One eyewitness account said that “the sky was split in two, and high above the forest the whole northern part of the sky appeared covered with fire…
“At that moment there was a bang in the sky and a mighty crash… The crash was followed by a noise like stones falling from the sky, or of guns firing.” In June 30, 2008, is the 100th anniversary of that ferocious impact near the Podkamennaya Tunguska River in remote Siberia–and after 100 years, scientists are still talking about it. “If you want to start a conversation with anyone in the asteroid business all you have to say is Tunguska,” says Don Yeomans, manager of the Near-Earth Object Office at NASA’s Jet Propulsion Laboratory. “It is the only entry of a large meteoroid we have in the modern era with first-hand accounts.”
The fireball is believed to have been 50-100m wide. It depleted 2,000 sq km of the taiga forest in the area, flattening about 80 million trees. This “Tunguska event” remains the most powerful of its kind recorded in history – it produced about 185 times more energy than the Hiroshima atomic bomb (with some estimates coming in even higher). Seismic rumbles were even observed as far away as the UK.
And yet, over a hundred years later researchers are still asking questions about what exactly took place on that fateful day. Many are convinced that it was an asteroid or a comet that was responsible for the blast. But very few traces of this large extraterrestrial object have ever been found, opening the way for more outlandish explanations for the explosion.
NASA says: “A century later some still debate the cause and come up with different scenarios that could have caused the explosion,” said Yeomans. “But the generally agreed upon theory is that on the morning of June 30, 1908, a large space rock, about 120 feet across, entered the atmosphere of Siberia and then detonated in the sky.”
It is estimated the asteroid entered Earth’s atmosphere traveling at a speed of about 33,500 miles per hour. During its quick plunge, the 220-million-pound space rock heated the air surrounding it to 44,500 degrees Fahrenheit. At 7:17 a.m. (local Siberia time), at a height of about 28,000 feet, the combination of pressure and heat caused the asteroid to fragment and annihilate itself, producing a fireball and releasing energy equivalent to about 185 Hiroshima bombs.
“That is why there is no impact crater,” said Yeomans. “The great majority of the asteroid is consumed in the explosion.”
Yeomans and his colleagues at JPL’s Near-Earth Object Office are tasked with plotting the orbits of present-day comets and asteroids that cross Earth’s path and could be potentially hazardous to our planet. Yeomans estimates that, on average, a Tunguska-sized asteroid will enter Earth’s atmosphere once every 300 years.
“From a scientific point of view, I think about Tunguska all the time,” he admits. Putting it all in perspective, however, “the thought of another Tunguska does not keep me up at night.”