On the morning of 30 June 1908, residents near the Tunguska River in Siberia saw a huge fireball streak across the sky, followed by a deafening explosion. The shock wave flattened 80 million trees over an area of 2,000 square kilometers, all radiating outward. The flash was visible hundreds of kilometers away, and the sound audible over 1,000 kilometers. Yet no impact crater has ever been found.
Account
On the morning of 30 June 1908 at 7:17 AM, residents near the Tunguska River in Siberia saw a huge fireball streak across the sky, followed by a deafening explosion. The shock wave flattened 80 million trees over an area of 2,000 square kilometers, all radiating outward from the blast center. The flash was visible hundreds of kilometers away, and the sound audible over 1,000 kilometers. In 1927, Soviet mineralogist Leonid Kulik led the first expedition to the blast center. He found vast areas of fallen trees but no impact crater. In 1961, abnormally high nickel and cobalt levels were found in the soil. In 2007, Italian scientists proposed that nearby Lake Cheko might be an impact crater.
Contested
No crater and no meteorite fragments have ever been found. The central trees were fallen but their top branches were scorched. The "white nights" phenomenon after the explosion caused nights to be as bright as day in various parts of Europe for several days. Competing hypotheses include comet, stony asteroid, antimatter, micro black hole, and alien spacecraft.
Sources
- Soviet Academy of Sciences archives
- Kulik expedition report
- multiple journal papers