Tuesday, April 01, 2008

Kofels v. Tunguska

Reader Skul brought up the 1908 Tunguska explosion that leveled a good part of Siberia.

You can get a sense of the magnitude of this event by comparing observations made at different distances. Seismic vibrations were recorded by sensitive instruments as much as 1000 km (600 mi) away. At 500 km (300 mi), observers reported "deafening bangs" and a fiery cloud on the horizon. About 170 km (110 mi) from the explosion, the object was seen in the cloudless, daytime sky as a brilliant, sunlike fireball; thunderous noises were heard. At distances around 60 km, people were thrown to the ground or even knocked unconscious; windows were broken and crockery knocked off shelves. Probably the closest observers were some reindeer herders asleep in their tents in several camps about 30 km (20 mi) from the site. They were blown into the air and knocked unconscious; one man was blown into a tree and later died. "Everything around was shrouded in smoke and fog from the burning fallen trees."

It is estimated that the force of the explosion was 1,000 times greater than the atomic bomb that devastated Hiroshima. If this explosion happened over Albany, NY, people on the Canadian side of Niagara Falls would be looking east saying "Whaaaaa?" Other descriptions of the explosion can be found here, here and here.

What is generally assumed is that an meteor entered the earth's atmosphere. Superheated by friction, it exploded about three miles over a very sparsely populated portion of Siberia and flattened everything over a two thousand square kilometer stretch of land (over 1,200 square miles). This meteoroid, producing a blast 1,000x more powerful than the Hiroshima bomb, was estimated to have been about 50 to 60 meters (160 to 200 feet) in diameter.

The Kofels explosion was caused by an meteoroid estimated to be 20x the size of the one that devastated Tunguska.

Neither the Kofels or the Tunguska events involved a meteor or asteroid actually impacting the earth. But this did happen just outside of Winslow, Arizona - Barringer Crater.
This is what happens when a Tunguska-sized meteroid (perhaps 50m, about 160 feet or so) hits the earth.

Oh yeah, that left a mark.

The crater is three quarters of a mile across and 700 feet deep.

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