Word: asteroid
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Dates: during 1980-1989
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Meteors, which are asteroids or cometary debris that has entered the atmosphere, continually shower the earth. Most of them are small and either break up or are burned to ash by frictional heat generated by their plunge through the atmosphere. But, explains Shoemaker, the incineration of larger asteroids is far more violent. An asteroid 80 ft. across, striking the atmosphere at 50,000 m.p.h., compresses the air in its path so much that in effect the asteroid is stopped dead in its tracks, converting kinetic energy almost instantaneously into heat, light and a powerful shock wave. That causes a tremendous...
...calculations suggest that asteroids packing the explosive energy of one megaton should enter the atmosphere on an average of once every 30 years, larger asteroids with a 20-megaton punch every 400 years, and a 1 km, 10,000- megaton comet or asteroid once in 100,000 years...
During the past few years, evidence has been accumulating to support Physicist Luis Alvarez's theory that a giant comet (or asteroid) struck the earth 65 million years ago, pulverizing a huge area and spewing so much debris into the atmosphere that the skies darkened for months, temperatures dipped, and much of the life on earth--most notably the dinosaurs--perished. It was the demise of the dinosaurs, many evolutionists believe, that enabled man's tiny mammalian ancestors to emerge from hiding, occupy the environmental niches left vacant by the great beasts and other destroyed species, and evolve into Homo...
...world may someday end with a whimper, but evidence is mounting that the dinosaurs went out with a bang. According to the much debated theory proposed by the father-son team Luis and Walter Alvarez in 1980, an asteroid or comet slammed into the earth at the end of the Cretaceous period, 65 million years ago, spewing so much dust into the atmosphere that sunlight was blocked for months. Temperatures plummeted, plants withered, and many species, including the mighty dinosaurs, perished en masse...
...Clemens' view, the discovery indicates that at least some dinosaur species were not sensitive tropic dwellers but were able to survive through chilly and dark Arctic winters lasting from November to February. That theory tends to undermine the currently popular asteroid version of the apocalypse. According to that model, all dinosaurs perished when an asteroid or comet collided with the earth and tossed obscuring dust into the air, blocking sunlight and lowering ground temperatures. Clemens counters that dinosaurs living up north would hardly have noticed the difference, let alone be wiped out. Says he: "It doesn't matter if your...