Tunguska: One Blast. 80 Million Trees. No Crater.Episode 141:35
The 20-Megaton Rock Only 70 Meters Wide
Scientists translate Tunguska's forest damage into the shock, heat and urban danger posed by a surprisingly small asteroid.
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Transcript
1 herder was blown into a tree, and later died.
It happened over Siberia June 30th, 1908, about 7:15 a.m.
Witnesses saw a fireball, a flash brighter than the Sun, then thunder.
Eyewitnesses reported a large explosion. Herders described forest burning, and many reindeer were lost.
At 37 miles, or 60 kilometers, witnesses fell, windows broke, crockery fell.
Exposed-skin burns were reported as far as 31 miles, or 50 kilometers, from impact.
Farther out, shocks broke windows 124 to 186 miles from the blast.
Later surveys found millions of trees flattened across a butterfly-shaped 830-square-mile zone.
Modern simulations put Tunguska-like damage near 20 megatons from a 230-to-295-foot object.
The primary hazards were shock waves and thermal radiation.
When scientist Leonid Kulik reached the site in 1927, trunks stood stripped, burned, and branchless.
But the expedition found no physical evidence of the bolide itself.
A NASA simulation study ran 10 million Tunguska-scale cases.
Semyonov saw the northern sky split apart, with fire above the forest.
Where it leaves off
Before Earth could prepare for another Tunguska, one final question remained: what exactly exploded over Siberia?
Sources
- 1908 SIBERIA EXPLOSION: Reconstructing an Asteroid Impact from Eywitness Accounts - Planetary Science Institutepsi.edusecondary
- 115 Years Ago: The Tunguska Asteroid Impact Event - NASAnasa.govsecondary
- NASA/Technical Memorandum (NASA/TM--220174) 2018ntrs.nasa.govsecondary
- Vurdalak | Witness: S. B. Semyonovvurdalak.comprimary
- AN ARCHIVAL AND ORAL HISTORY OF THEhou.usra.edusecondary
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