A new theory emerges to explain the enigmatic Tunguska Event.
On a June morning in 1908, above a sleepy forest in the Siberian Taiga plush with larches, spruces, and black bears, something flashed so bright and hot in the sky that a hunter 10 miles away, near the Middle Tunguska River, tore his shirt off thinking it was on fire. Locals described some variation of a “fiery ball flying north.” A loud explosion, releasing the equivalent of three to five megatons of TNT, followed. The resulting shock wave, the largest in recorded history (185 times more powerful than the Hiroshima bomb), spread out over 1,000 square miles. Some 30 people were in the vicinity. Many of them were knocked unconscious, and at least three were killed. Houses and millions of trees toppled over and charred. Somehow, hours later, astronomers in Europe and Asia witnessed a night sky so bright that, “at midnight,” according to one testimony, “it was possible to read the newspaper without artificial lights.”
For a time, it seemed that a similarly mysterious event may have happened in 2013—again over Russia. Near the snow-covered factory town of Chelyabinsk, a 66-foot meteor exploded over the hills, 16 miles above ground. It, too, for a moment, burned brighter than the sun, and emanated intense heat, according to eyewitness reports. The Chelyabinsk meteor blasted down doors and shattered windows in a nearby town, injuring over 1,000 people. Then a hole was discovered in a frozen lake, and a half-ton chunk of space rock was found in the lakebed.
The so-called “Tunguska event’’ is different. It remains a mystery. After decades of scientific expeditions, no one has found a crater or any debris from a meteorite or comet—nothing to conclusively indicate a violent collision with the Earth. In their 2008 book, The Tunguska Meteorite: 100 Years of the Great Puzzle, authors A.I. Voitsekhovskii and V.A. Romeiko catalog 66 theories about the event. Lots of them are implausible (for example, a gaseous explosion emanating from the bowels of the earth). But some are less far-fetched. Recently a new theory has joined the fray, positing that a “dark asteroid,” composed of light-absorbing iron, caused the destruction and the peculiar light show.
DEADLY WAKE:
This photograph was taken in 1927 during the first Soviet research
expedition,
led by Russian meteorologist Leonid Kulik, to uncover the
cause of the Tunguska event. He was able
to interview local witnesses
but left without any evidence of an impact.Wikimedia Commons
Over the years, the Tunguska enigma has seeped into the imagination of popular culture and science fiction. In Indiana Jones and the Kingdom of the Crystal Skull, the Tunguska event is suspected to be a result of cosmic tourism, as cadavers found at the blast site are discovered to be interdimensional travelers. In Star Trek, the Tunguska event is seen as the result of Vulcan good will: A devastating meteor was headed toward Western Europe and a Vulcan survey ship deflected it into the relatively uninhabited forest. The X-Files ran an episode called “Tunguska,” where a military expedition mining meteoric remains discovers a black oil harboring alien microbes capable of possessing human bodies. Isaac Asimov took a shot at explaining it in his story, “The Mad Scientist.” Even Ghostbusters references it.....MUCH MORE
Early theories ranged across the space-rock spectrum. One is that a comet caused the Tunguska event. A flying fireball, after all, is a common description of a comet, even though comets are made of ice. Their mostly icy composition somewhat accounts for the absence of any meteoric material near the event site, since burning ice would vaporize. The forest-felling blast from a comet is also conceivable, since it could, in theory, explode after colliding with the dense air close to Earth. (The Chelyabinsk meteor, speeding at over 40,000 miles per hour, shattered upon contact with the troposphere, the thin bubble of breathable air that we inhabit, as if it were a brick wall.)
“But a comet is not just made of ice,” Vladimir Pariev, an astrophysicist at the Lebedev Physical Institute of the Russian Academy of Sciences, in Moscow, is quick to point out. “It also includes some stone and, if a comet of that size would have exploded over Siberia, there would have almost certainly been some debris discovered.” He doesn’t outright reject the possibility of a comet but acknowledged the difficulties surrounding that hypothesis, such as its inability to explain the bright night sky witnessed over Europe several hours later. But if it wasn’t a comet, what could cause such destruction?....
