Sunday, September 20, 2009
NatGeo explores asteroid explosion over Sahara producing glass deposits; would produce Armageddon today
On Sunday September 20, National Geographic aired an important one-hour documentary on the asteroid impact issue, called “Ancient Asteroid,” with link here. The film is written by Richard Reisz.
The Sahara Desert has been a “sand ocean” for only a few thousand years. But about thirty million years ago something happened in the area to cause an enormous amount of green-yellow glass to form over an area a few hundred miles SW of Cairo.
Most natural glass is volcanic in origin, but the scientific evidence, developed by physicist Mike Boslough, indicates that a partially broken or loosened asteroid exploded above the area, sending an enormous plume a hundred kilometers into the atmosphere and heating the ground to thousands of degrees.
The same kinds of event may explain the Tunguska Explosion in Siberia in 1908, but it was smaller. The film shows simulations of Tunguska, and computer animated simulations of this Sahara explosion.
A similar glass surface about 600 yards wide was formed by the Trinity atomic bomb blast in New Mexico in July 1945, but it was much smaller even than Tunguska.
Even a Tunguska-sized asteroid over a major city could kill millions without warning, and such impacts may occur about once a century somewhere on the planet.
The idea of hitting an asteroid with nuclear weapons (as in the 1998 movie “Armageddon”) to break it into pieces might just cause an even bigger high-altitude blast.
The film also covers the Shoemaker-Levy Comet collision with Jupiter in 1994, NASA link here.
A glass deposit seems to exist in far northern California, north of Mount Shasta; I visited it in 1975.
Attribution link for Wikipedia/NASA photo of Africa. http://en.wikipedia.org/wiki/File:Africa_satellite_orthographic.jpg .