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Tunguska blast 100 years ago

Date: 30-Jun-08
Author: NASA Jet Propulsion Laboratory

At around 7:17 on the morning of June 30, 1908, a man based at the trading post at Vanavara in Siberia is sitting on his front porch. In a moment, 40 miles [64 km] from the center of an immense blast of unknown origin, he will be hurled from his chair and the heat will be so intense he will feel as though his shirt is on fire. The man at the trading post, and others in a largely uninhabited region of Siberia, near the Podkamennaya Tunguska River, are to be accidental eyewitnesses to cosmological history.

While the impact occurred in 1908, the first scientific expedition to the area would have to wait for 19 years. In 1921, Leonid Kulik, the chief curator for the meteorite collection of the St. Petersburg museum led an expedition to Tunguska. But the harsh conditions of the Siberian outback thwarted his team's attempt to reach the area of the blast. In 1927, a new expedition, again lead by Kulik, reached its goal.

Although testimonials may have at first been difficult to obtain, there was plenty of evidence lying around. Eight hundred square miles [2070 sq km] of remote forest had been ripped asunder. Eighty million trees were on their sides, lying in a radial pattern.

Rare remnant of trees fallen during the Tunguska event. Courtesy: V. Romeiko

The massive explosion packed a wallop. The resulting seismic shockwave registered with sensitive barometers as far away as England. Dense clouds formed over the region at high altitudes which reflected sunlight from beyond the horizon. Night skies glowed, and reports came in that people who lived as far away as Asia could read newspapers outdoors as late as midnight. Locally, hundreds of reindeer, the livelihood of local herders, were killed, but there was no direct evidence that any person perished in the blast.

Full story: 100 Years of Space Rock: The Tunguska Impact

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