What was the Tunguska Event and When Did it Happen?

More than a century since it happened, the cause of the Tunguska Event remains a mystery. Some believed it was the wrath of a god, while theories have pointed to everything from a nuclear bomb to a comet to an alien encounter.

What is not in doubt is the impact the incident had on the Siberian landscape, and the fascination the subject holds to this day.

The Tunguska Event was an enormous explosion in the skies above Siberia’s Stony Tunguska River. It occurred at approximately 7:14am on 30 June 1908 and exerted a force of between 10 and 30 megatons of TNT. Instantly, eighty million trees covering some 500,000 acres were flung backwards. The result was a dramatic radial pattern of flattened forest from the blast’s epicentre. Locals saw animals thrust into the air and spoke of the ground shaking, of fireballs lighting up the sky and emitting scorching heat felt forty miles away. In London, England, there were reports of a flash of light and the shock waves were recorded in Western Europe.

With so many witnesses, it may seem surprising that the cause of the Tunguska Event remains elusive. In terms of local accounts, they were spread far and wide in this remote part of Russia. Some were reluctant to discuss the matter, believing it was the work of the deity Ogdy, a thunder god whose legend stretched back into Siberia’s mysterious past. What’s more, the harsh Siberian conditions meant the first scientific examination of the site didn’t take place until 1921. All of this hampered the collection of data and undoubtedly added to the incident’s mystique.

The prevailing theory of the cause of the Tunguska Event holds that an asteroid up to 262 feet wide entered the Earth’s atmosphere at roughly 34,000 miles per hour and exploded in mid-air. A 2019 NASA report used computer models and data from a 2013 meteor entry in Chelyabinsk to determine that this was the most likely scenario.

The Tunguska Incident has been called the largest impact event in recorded history. But there was one crucial aspect missing. If a rock as wide as the wingspan of a 747 plummeted to Earth at fifty times the speed of sound, then exploded at a force equivalent to the 1980 eruption of Mount St. Helens, it would surely leave something of a dent. But there was no Tunguska Crater. And barely any fragments were found. The generally held explanation for this is that the heat and pressure eviscerated the vast majority of the asteroid.

It’s fair to say that modern technology and scientific advances have provided the most likely explanation for the Tunguska Event. Nevertheless, there remains no definitive answer. And without asteroid fragments, with no crater, but with the dramatic images of its aftermath, there will always be doubts. There will always be those who think the truth is still out there.