It Came from Outer Space and Nearly Killed Us All: The Story of the 1908 Tunguska Blast

  “Suddenly the sky was split in two...the whole northern part of the sky was covered with fire.  There was a bang in the sky and a mighty crash.  The earth trembled.” -from an eyewitness account of the Tunguska Event recorded in 1927.

The night sky glowed an eerie phosphorescent blue from the fire of the explosion.  It was reported that the dark sky was so illuminated by what happened that night over northern Siberia that people as far away as China could read a newspaper outdoors at midnight.

It sent shockwaves all across Europe and Asia.  In London and Washington D.C. seismographs registered the event as a small magnitude earthquake.  The sound could be heard as far away as St. Petersburg and the explosion is said to have broken glass in Moscow.  Within hundreds of miles of the epicenter dust particles thrown into the atmosphere blotted out the sun for days.

On the morning of June 30, 1908 there was a massive explosion that occurred over what is now the Russian province of Krasnoyarsk Krai deep in Siberia near the banks of the Tunguska River.  The Tunguska Event, sometimes referred to as the Tunguska Blast, was the largest ever recorded extraterrestrial impact event in human history.  This one single explosion is estimated to have had the destructive force of over 30 megatons of TNT. 

To put the explosive force of the Tunguska Event in proper perspective, the most powerful weapon currently in the nuclear arsenal of the United States is the B83 laser guided bomb.  Known as the “nuclear bunker buster” the B83 bomb has a maximum explosive yield of 1.2 megatons of TNT, or about twenty-five times less explosive force than the Tunguska Blast of June 30, 1908.

Today, many scientists believe that the Tunguska Event might only have been surpassed by an extraterrestrial impact event which may have driven dinosaurs extinct during prehistoric times.

The Tunguska Blast flattened over 830 square miles of forest; toppled an estimated 80 million trees, killed tens of thousands of reindeer and claimed an unknown number of lives even in one of the world’s most sparsely populated regions.  

Krasnoyarsk is the largest city in the Siberian province of Krasnoyarsk Krai where the Tunguska Event occurred.  Today the city of Krasnoyarsk has a population of over 1,000,000 and is an important junction on the Trans-Siberian Railroad that snakes across Russia from Europe to the Pacific Ocean.  Despite being the largest city in the province of Krasnoyarsk Krai the city of Krasnoyarsk itself is still a full two hour flight, and over 600 miles, from the site of the Tunguska Event.

On July 13, 1908 Krasnoyaretz the local newspaper for the city of Krasnoyarsk reported that, “At 7:43 (on the morning of June 30) noise akin to a strong wind was heard.  Immediately afterward a horrific thump sounded followed by an earthquake that literally shook the buildings as if they were hit by a large log or heavy rock.”

Though reported on in local newspapers at the time, and though the Tunguska Event was heard and even felt throughout large parts of the world, due to the site’s remote location and to both social and political upheaval in the area as a result of the Russian Revolution of 1917, a thorough investigation of what happened near the Tunguska River in 1908 would not be launched until nearly twenty years later in 1927.

That year Russian mineralogist Leonid Kulik received permission from the Soviet government to lead an expedition to the site of the Tunguska Event.  Kulik and his team, led by local Eveniki hunters many of whom had witnessed the blast firsthand, journeyed to the very center of the explosion area where they expected to find an enormous impact crater.

Leonid Kulik on site in Tunguska

However, instead of finding an impact crater Kulik and his team came upon a five square mile area where burnt trees were left scorched and charred, devoid of foliage, but standing completely upright!  And for miles around this center area of upright trees, stretching off into the distance, were row upon row of bent trees, flattened and all radiating out in different directions from the center spot like the spokes of a wheel as if the hand of God had pushed them all down flat to the earth.

Eventually, it was determined that the area of flattened forest encompassed 830 square miles and that its shape resembled that of a gigantic butterfly with a wingspan of 43 miles and a length of over 50 miles.

Kulik found many small holes filled with water among the flattened trees.  He deduced that these craters were caused by meteorite impacts, but upon draining one of the larger holes and discovering a tree stump standing at the bottom, Kulik’s meteorite impact crater hypothesis was proven false.

So if a meteor did not actually fall to earth and cause the mammoth blast at Tunguska that shook the world what did cause the largest explosion ever recorded in all of human history?

The Epicenter of the Tunguska Blast in 1927

Today it is widely believed that an asteroid travelling at over 33,000 miles per hour entered the earth’s atmosphere on June 30, 1908.  Scientists estimate that the asteroid probably weighed somewhere over 220 million pounds and that as the enormous rock entered the earth’s atmosphere, it heated the air around it to an astonishing 45,000 degrees Fahrenheit!  As the asteroid plunged to earth in Siberia a combination of extreme temperature and pressure caused the giant rock to explode and created a blast at about 28,000 feet above the earth’s surface that would have had the equivalent explosive force of  approximately 200 atomic bombs like the one dropped on Hiroshima during World War Two.

Lucky for us, it is thought, that had the asteroid which exploded above the earth near the Tunguska River in Siberia actually made landfall and impacted with the earth’s surface than it very well could have made the human race extinct, since such an impact would have thrown so much dust, dirt and debris into the earth’s atmosphere that it would very likely have blotted out the sun completely and turned day into night permanently for the entire world.

Had an asteroid entered the earth’s atmosphere in a more densely populated area of the world than the region near the Tunguska River in Siberia it would have been capable of completely vaporizing  a city three times the size of New York!

This is the leading theory behind the Tunguska Blast of 1908 and is widely agreed upon by most in the scientific community.  However, there is one other prominent and just as plausible theory that some use to explain the cause of the largest explosion in recorded history.

Epicenter of the Tunguska Blast Today

In 1930, shortly after Kulik’s first expedition to the site of the explosion, British astronomer F.J.W Whipple, who was the superintendent of the Kew Observatory in London, suggested that the Tunguska Event may have been caused by a comet entering the earth’s atmosphere.

He believed that since comet’s are composed of materials such as water, ice and frozen gasses, all traces of a comet would have been vaporized once it entered the earth’s atmosphere, which would account for the lack of an impact crater at the Tunguska site.

In 1978 an astronomer working for the Soviet bloc named Lubor Kresak proposed that it could have been the Comet Encke which caused the Tunguska Blast.  The Comet Encke is a small comet that periodically enters the orbit of the planet Jupiter and generally stays there for a period of three years, and Comet Encke is also the specific comet which is responsible for Beta Taurids an annual meteor shower near Jupiter which takes place between June 28 and June 30 and can be observed from earth via radio telescope.  

Kresak theorized that somehow during one of its trips through Jupiter’s orbit at the height of the Beta Taurid meteor shower in 1908 Comet Encke had somehow been thrown off course and went careening towards earth before finally disintegrating just about the earth’s surface over Siberia.  It is interesting to note that during the Cold War it was the comet theory which was most widely accepted by scientists within the Soviet Union as the true explanation for the Tunguska Blast of 1908, despite the fact that the theory was first proposed by a British astronomer, while proponents of the asteroid theory proliferated in both the United States and the United Kingdom

Today, some debate still rages between proponents of the asteroid theory and supporters of the comet theory when it comes to explaining the Tunguska Blast and there are thousands of scholarly papers published on the event each year in the United States and Europe.

Most recently, in June of 2007, scientists from the Italian University of Bologna asserted that a bowl shaped lake in the region called Lake Cheko located about 5 miles from the epicenter of the Tunguska Blast may, in fact, be an impact crater from the 1908 event.

The University of Bologna study asserts that Cheko, “a small lake located in Siberia close to the epicenter of the 1908 Tunguska explosion might fill a crater left by a fragment of a cosmic body.”

Lake Cheko in Siberia

The Italian scientists do not dispute the fact that the Tunguska Blast was primarily caused by a mid-air explosion, but rather, their only assertion is that large fragments of what might have been an asteroid did most definitely impact the earth’s surface on that fateful morning of June 30, 1908 and forever irrevocably alter the landscape of Siberia.

For generations the debate in the scientific community over whether the Tunguska Blast of 1908 was caused by an asteroid, a comet, an impact with earth, a mid-air explosion or any combination of the above is likely to continue.  However, when it comes to what happened in Siberia over 120 years ago there is one thing that we can all be thankful for.  We can all be thankful that the earth and humanity, unlike our dinosaur predecessors, survived the greatest explosion ever recorded.  And perhaps we would all be wise to keep a watchful eye on the skies above and pray that nothing like what caused the Tunguska Blast of 1908 ever falls from outer space again...