The Disaster That Returns Every 2,000 Years

Name: The Disaster That Returns Every 2,000 Years
Genre: Documentary

Tunguska changes from a historical anomaly into a recurring planetary risk measured in millennia.

This episode needs All Access, from $4.99 a week.

Transcript

A herder was blown into a tree. Later, he died.
The blast began above Siberia on June 30th, 1908. Eyewitnesses saw a fireball, then heard an explosion.
NASA places the local time at about 7:15 a.m.
A Planetary Science Institute account puts the event at 7:17 a.m.
Semyonov described the northern sky splitting apart, with fire above the forest.
Modern models converge on 10 to 20 megatons released high in the atmosphere.
Shock waves broke windows 125 to 185 miles, or 200 to 300 kilometers, away.
Exposed skin burned as far as 31 miles, or 50 kilometers, from the blast.
The Soviet Academy sent geologist Leonid Kulik to the site in 1921.
The inaccessible terrain stopped him before he could reach it.
Kulik reached Tunguska in 1927 and found burned, stripped trees. Near the center, trunks stood while branches had vanished.
Later surveys mapped a butterfly-shaped destruction zone of 830 square miles.
Millions of trees fell, yet the object left no obvious ground crater. A mid-air explosion most likely vaporized it.
Most scientists today believe Tunguska was caused by an asteroid. Tunguska research's main constraint is lack of quantitative data.
Semyonov said he had just raised an axe before the northern sky split apart.
NASA-calibrated estimates put an Earth impact this size every 2,000 to 4,000 years.
A land impact is three times less frequent, and low population density limited human casualties.
No fragments from the exploding object have ever been recovered.

The next Tunguska-sized object could be only 70 to 90 meters wide—and it might not arrive over an empty taiga.

All Access is $4.99 a week, $14.99 a month or $39.99 a year. The annual plan starts with three days free.

Renews until you cancel. Terms · Privacy