Tuesday, December 16, 2008

History Channel: The Universe: Deadly Comets and Meteors


The History Channel “Universe” program tonight is accompanied online by a three-minute video “Comets of Doom”, link here.

The “main course” of this “Universe” installment was called “Deadly Comets and Meteors”. The program started with mention of a website that allows one to calculate the effect of a given sized asteroid at a given location. The asteroid that caused the Chicxulub Crater near the Yucatan 65 million years ago, if it hit Los Angeles, would also destroy San Francisco with the “fallout” from the plume.

The film used the terms asteroid and meteorite more or less interchangeably, and most of the rest of the hour long film was a descriptive exploration of asteroids and comets in general.

The film talked about carbonaceous and ordinary meteorites. It moved to comets, and a female scientist made a “comet” in a laboratory with corn syrup, window cleaner, and dry ice. The film described Halley’s comet and then the Mam belt of comets in the regular orbits similar to those in the asteroid belt. Some comets that could threaten Earth could come from the Oort Cloud outside Pluto, extending to almost a light year.

The film then explored the idea that both meteorites and asteroids helped seed the Earth with life. Comets could have provided enormous quantities of water, and asteroids seem to have primitive amino acids, or at least their building blocks.

The film went back to the possible threats, including a small asteroid hit in 2029, which could be large enough to destroy a city, but had less than 1 chance in 40000 in striking. The film also showed comet Shoemaker-Levy (NASA link) which hit Jupiter in 1994. Jupiter protects Earth from most major asteroid and comet hits. We owe our lives to Jupiter. The film briefly described the Tunguska explosion over Siberia in 1908. There is an article by Charles Q. Choi in Space "Huge Tunguska Explosion Remains Mysterious 100 Years Later," link here.

At the end of the film there was a comment that a major strike of some kind would occur within the next 1000 years. But you don't need asteroid insurance, nor can you get it.

There was a related "Mega Disasters" entry (2 films, one on comets, one on asteroids) reviewed on this blog Sept. 5, 2007.

No comments: