Word: comets
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Except for a sudden dash across the sky by Halley's comet--which appears about as often as the Patriots do in the Super Bowl--not much is going to deter 90 million Americans from watching the big game this Sunday...
...20th century has spawned some notions about comets that seem even more fantastic than the ancient myths. British Astronomers Fred Hoyle and Chandra Wickramasinghe have suggested that over hundreds of millions of years, primitive biological entities, perhaps even cells, developed within some comets. These may have been delivered to the earth as the first form of terrestrial life by a comet that impacted billions of years ago. Francis Crick, co-discoverer of the DNA molecule's structure, and Organic Chemist Leslie Orgel have proposed a less fanciful theory: Comets brought with them the chemical precursors of life, in the form...
...That comets do occasionally strike the earth seems certain. Some scientists think a tiny chunk of a comet, exploding in the atmosphere above Siberia in 1908, caused a tremendous blast and fireball in the Tunguska region, felling trees in a 200-sq.-mi. area and knocking the nearest residents (40 miles away) off their feet...
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...
...that Halley's is visible either through binoculars or to the naked eye, it will appear to move among the constellations. On the day you plan to look for Halley's, find the point on the chart that approximates the chosen date. This spot will help you determine the comet's position relative to familiar groups of stars. But the time of day for observing Halley's and the direction in which to look will vary. This week, for example, observers in the northern hemisphere should search the southwestern sky during the evening. The best view is on clear, moonless...