The Tunguska Event
It happened on June 30, 1908. A fireball ripped through the daytime sky above a remote forest in Siberia, close to the Podkamennaya Tunguska river. Moments later, a roaring shockwave rattled homes and knocked people off their feet. Today, it is known as the Tunguska Event.
The explosion depleted some 2,000 sq km of forest in the area, flattening roughly 80 million trees in the sparsely populated Eastern Siberian Taiga. Despite being over 35 miles away, residents in the nearest town felt heat from the blast, windows were smashed in, and the resulting shock wave was equivalent to a 5.0 magnitude earthquake.
The Tunguska Event is the largest impact event on Earth in recorded history, and yet, over 100 years later, scientists still aren’t quite sure just what happened on that day. Most credible scholars think it was an asteroid or comet, but no one is exactly sure which. The surrounding circumstances of the investigation have only further muddled things, leading to other strange theories as well.
So just what did happen that day? Here’s what we know.
In 1927, a Russian team led by Leonid Kulik was the first to make a trip to the area for research purposes, nearly 20 years after the blast. The reasons for this delay were twofold. For one, the Tunguska region of Siberia is remote and inhospitable, with long, cold winters. Simply put, the area is tough to get to. Added to this was the political climate in Russia during the early 20th century. WWI and the Russian Revolution were on the horizon, and scientific curiosity just wasn’t a priority at that time.
When Kulik and his team finally did get to the site, the damage was still very much apparent. Kulik proposed that a meteor was responsible for the explosion. One fact still puzzled him though. There was no impact crater or meteorite fragments.
A few years later, other Russian researchers suggested it was a comet, not a meteor, that caused the explosion. Unlike rocky meteorites, comets are made up of ice. The icy composition of the impact object would explain the lack of rock fragments.
However, in a 1958 expedition to the site, researchers found microscopic silicate and magnetite remnants when sifting through the soil in the area. Chemical analysis showed that they contained high levels of nickel, which is a known feature of meteoric rock. This would support the theory that the blast was caused by a meteor, so the debate of just what exactly hit Earth continued.
Since scientists could not definitely declare a cause, strange alternative theories began to arise.
One suggestion was that the Tunguska Event could have been caused by matter and antimatter colliding. A collision between any particle and its antiparticle partner leads to their mutual annihilation, and energy is released. Another theory was that the explosion was caused when a black hole collided with Earth.
Other scientists suggested geological origins. Astrophysicist Wolfgang Kundt proposed that the Tunguska Event was caused by the release, and subsequent explosion, of natural gas from the Earth’s crust.
Of course, one of the more bizarre ideas was that an alien spacecraft crashed at the site, searching for fresh water in Lake Baikal.
(How is it that aliens can have the advanced technology necessary for interstellar travel, and yet always seem to clumsily crash into Earth?)
In the end, it’s no real surprise that such theories arose. A large explosion, little evidence, and no consensus – all the makings for pseudo-scientific explanations to crop up.
Comet or Asteroid?
Even given these alternative theories, today most credible scientists still would conclude that the impact was extraterrestrial in origin. But questions of just what it was still linger. Was it an asteroid or a comet?
In the end, it might not really matter. What does matter is that over 100 years ago, there was a huge impact on Earth. We know our planet has been hit before in the past, and will get hit again in the future.
Thankfully, we have scientists today who have set their sights to the sky. Through their massive telescopes, they search for early warnings of another potential strike.
If anything, the Tunguska Event serves as a reminder of the awesome power of the cosmos.
Mark Heald is an Associate Product Manager and Sporcle Admin. He enjoys spending time with his family, traveling, and bemoaning the fact the Sonics left Seattle.