Wednesday, September 05, 2007
History Channel: Mega Disasters on comets, asteroids
This particular blog, smaller than many others, is set up to remind visitors of some of the life-changing external threats out there, those bolts from the blue, especially when these apocalyptic potentialities are documented in films (usually documentaries) and television shows (often on cable). On the blog, I try to present the appearance of new films as “news items” that may alert the public to some particular possible disaster. The discussion is more about the newsworthiness of the content than a review of the object merit of the show as a “film”.
The History Channel seems to be adding to its “Mega-Disaster” series (they go alone pretty well with Weather Channel’s “It Could Happen Tomorrow”). During the first week of September, 2007, The History Channel presented “Asteroid Apocalypse” and “Comet Catastrophe,” each one-hour shows. These supplement shows already reviewed about earthquakes.
A comet is a soft ball of ice, sometimes a few miles across, that usually revolves in a highly eccentric orbit around the sun, sometimes reaching as far from the Sun as the Oort cloud. An asteroid is a planetoid, a piece of rock that somehow didn’t get consolidated into a planet. Most asteroids circulate between Mars and Jupiter (Ceres is the largest, over 400 miles across) but a small percentage may cross the Earth’s orbit. The orbits of Asteroids are usually less eccentric than those of comets.
The last major asteroid strike may have occurred 65 million years ago near the Yucatan, resulting in the extinction of the dinosaurs, the appearance of modern birds and mammals, which had a competitive advantage in a world so suddenly changed. The last major comet impact might have occurred around 2807 BC a few hundred miles east of Africa in the Indian Ocean and caused the great Flood in Genesis. Historical migrations and “Babel” language development may support that hypothesis. Comet impacts may be more common than asteroid impacts, and the presence of Jupiter in our Solar System as a “vacuum cleaner” (Jupiter took a major hit in 1994) may well protect us and account for the fact that we can be here. The Tunguska explosion in Siberia in June 1908 was probably a "moderate sized" comet.
Both kinds of catastrophes would have similar consequences. Both can result in a huge fireball, earthquakes, and tsunamis hundreds of feet high, followed by a “nuclear winter” and possibly the end of technological civilization as we know it. An asteroid the size of a football field (100 yards) could wipe out a city. Either a comet or asteroid of several kilometers in diameter could punch through the atmosphere and result in an extinction event. The films “Deep Impact” and “Armageddon” in 1998 explored these possibilities.
The asteroid film presented Space Guard, with seven tracking telescopes (in the US, Hawaii, and Australia) to detect NEO ‘s (Near Earth Objects). An asteroid that has a narrow miss might return on the next orbit if it passes through a "keyhole". It seems as though there may a better chance of preventing an asteroid hit than a comet hit, and that unavoidable comet hits might be more likely, "eventually" as topologists say.
(See also July 25, 2006 on this blog.)
Update: Sept. 15, 2007
A review of an important 2005 History Channel film on bird flu (The Next Epidemic: Avian Influenza) was posted Sept. 15 on the TV blog, here.
Update: On Oct. 7, 2007 The History Channel presented "Siberian Apocalypse" about the 1908 Tunguska explosion over Siberia, 600 miles north of Lake Baikal. The most likely theory is a stony asteroid or carbonaceous chondrite. But other theories, including plasma ball lightning, were discussed. A similar fictitious explosion of New York City was simulated. There is a review of a short film "Russian Roswell" here on my TV blog.