Meteor Essays - Meteor Crater, Meteorite, Impact Event,

Meteor Crater Early in the history of the solar system, when space was cluttered with the materials of its formation, the planets and their moons were heavily bombarded by meteorites. Some of the members of the solar system (Mars, Mercury and our moon, for example) still show the residuals of the primordial rain of iron and stone. On our dynamic planet earth, erosion by weather, water and ice and the continuous reshuffling of crustal plates have erased most of the evidence of that early cratering. The solar system, not yet completely clear of the cosmic debris which was left over at its birth, continued to rain small meteorites down upon the planets, and occasionally the earth is struck by an object large enough to excavate a sizable hole. Dozens of meteorite impact craters have been recognized on the crust of the earth. In most cases, erosion has removed all but the shattered root zones of the craters. The most famous terrestrial impact crater is in the desert near Winslow, Arizona. Origin of Meteor Crater What happens when an irresistible force meets an immovable object? Meteor Crater! 50,000 years ago, a huge iron-nickel meteorite, hurtling at about 40,000 miles per hour, struck the rocky plain of Northern Arizona with an explosive force greater than 20 million tons of TNT. The meteorite estimated to have been about 150 feet across and weighing several hundred tons, in less than a few seconds, left a crater 700 feet deep and more than 4000 thousand feet across. Large blocks of limestone, some of them, the sizes of small houses were heaved onto the rim. Flat-lying beds of rock in the crater walls were overturned in fractions of a second and uplifted permanently as much as 150 feet. Today, the crater is 550 feet deep, and 2.4 miles in circumference. Twenty football games could be played simultaneously on its floor, while more than two million spectators observed from its sloping sides. In 1902, Daniel Moreau Barringer, a Philadelphia mining engineer, became interested in the site as a potential source for mining iron. He later visited the crater and was convinced that it had been formed by the impact of a large iron meteorite. He further assumed that this body was buried beneath the crater floor. Barringer was correct. The crater was formed by a meteorite impact, but what he did not know was that the meteorite underwent total disintegration during impact through vaporization, melting and fragmentation. In 1903, he formed the Standard Iron Company and had four placer mining claims filed with the federal Government, thus obtaining the patents and ownership of the two square miles containing the crater. Barringer spent the next 26 years attempting to find what he believed would be the giant iron meteorite. Barringer never found what he was looking for, but he did eventually prove to the scientific community that the crater was the site of a meteorite impact. ATextbooks are concerned with presenting the facts of the case (whatever the case may be) as if there can be no disputing them, as if they are fixed & immutable. And still worse, there is usually no clue given as to who claimed these are the facts of the case, or how [emailprotected] discovered these facts (there being no he or she, I or we). There is no sense of the frailty or ambiguity of human judgment, no hint of the possibilities of error. Knowledge is presented as a commodity to be acquired, never as human struggle to understand, to overcome falsity, to stumble toward the [emailprotected] -Neil Postman. The End of Education Grove Karl Gilbert, the first person to conduct a full scientific survey of the mysterious crater in the Arizona desert, was the most renown geologist of his generation, and has been described as Aperhaps the closest equivalent to a saint that American science has yet produced. (Hoyt, p37) He was tolerant, generous, and fair-minded, with an intense dislike of controversy of any kind. As chief geologists of the U.S. Geological Survey, his prestigious demeanor was held in high esteem. such that none of his colleagues or successors were willing to publicly question his conclusions-even when it became apparent that some of those conclusions had been wrong. In 1891, Gilbert became interested in reports of a large collection of nickel-iron meteorites found in the neighborhood of a gigantic circular crater in the Arizona desert. Since he had already speculated on the possible consequences of al large meteorite striking the earth, he decided to visit the crater and try to determine