The cause of the massive explosion that occurred in Siberia in 1908 remains a mystery to this day.

On June 30, 1908, a colossal explosion shook a secluded forest in Siberia, near the Podkamennaya Tunguska river. The blast was so intense that it flattened over 80 million trees across 820 square miles (2,123 square kilometers), with later comparisons likening it to 1,000 atomic bombs.

People from over 40 miles (64 kilometers) away witnessed a fireball brighter than the sun, followed by intense heat that knocked many off their feet. The blast's effects even reached as far as Great Britain. However, due to the political chaos in Russia at the time—amidst two revolutions and a world war—the Tunguska event wasn't thoroughly investigated until almost two decades later, when a scientific team led an expedition to the site in 1927.

Over a century later, questions about the 1908 event persist. Ben Bowlin and Matt Frederick from Stuff They Don't Want You To Know are joined by Joe McCormick from Stuff to Blow Your Mind to analyze the available evidence and explore the true cause behind Fire in the Sky.

The Tunguska explosion of 1908 was so extraordinary that numerous theories about its origin have emerged. Some suggest it was a comet or meteorite that exploded mid-air, while others speculate that Agda, the Thunder God, caused the blast out of anger toward the Siberian Evenki people. One theory even proposes an alien spacecraft, trying to reach the nearby Lake Baikal for water, exploded just before landing. However, no evidence of a spacecraft has ever been found, discrediting this theory for even its staunchest advocates.

In 1973, two scientists proposed that a miniature black hole collided with Earth, triggering an antimatter explosion that passed through to the other side. However, no trace of any exit wound or similar damage has ever been reported, making this theory easy to dismiss.

Another theory suggests that the explosion was caused by the renowned inventor Nikola Tesla testing his proposed "death ray," a particle-beam weapon meant to prevent any form of attack. Tesla often spoke of this invention, hoping it would end all wars. Could he have tested it in the remote Siberian region? Or perhaps he was attempting to send a wireless signal from his Wardenclyffe Tower in New York to explorer Robert Peary in the North Pole, but accidentally struck the Tunguska area instead?

This theory has been widely criticized because there is no evidence that Tesla ever developed such advanced technology. Any device capable of causing the Tunguska explosion would have needed the 1908 New York power grid to operate, which would not have been able to generate the immense energy released by the event.

The leading theory suggests that an impact event occurred, where a meteorite, comet, or asteroid struck Earth. However, a key issue arises: no crater has been found in the Tunguska area. The only evidence left of the explosion was the flattened trees. How could such an impact happen without leaving behind any impact crater?

In 2007, a group of Italian scientists proposed that the nearby small Lake Cheko could be the hidden crater, with the asteroid lying at the bottom, waiting to be discovered. Yet, some argue that their evidence is not strong enough to withstand further investigation.

What do Matt, Ben, and Joe believe? Could it have been a comet, primarily made of ice, that exploded in midair due to atmospheric stress, its pieces disintegrating? Or perhaps a rocky meteorite, which shattered into fine dust that settled deep into the soft, peat soil, making it hard to detect? Tune in to the full podcast to uncover the answer, or at least hear Joe perform an eerie chant to the Evenki thunder god.