CraterEarly in the history of the solar system, when space was cluttered with thematerials of its formation, the planets and their moons were heavily bombardedby meteorites.
Some of the members of the solar system (Mars, Mercury and ourmoon, for example) still show the residuals of the primordial rain of iron andstone. On our dynamic planet earth, erosion by weather, water and ice and thecontinuous reshuffling of crustal plates have erased most of the evidence ofthat early cratering. The solar system, not yet completely clear of the cosmicdebris which was left over at its birth, continued to rain small meteorites downupon the planets, and occasionally the earth is struck by an object large enoughto excavate a sizable hole. Dozens of meteorite impact craters have beenrecognized on the crust of the earth.
In most cases, erosion has removed all butthe shattered root zones of the craters. The most famous terrestrial impactcrater is in the desert near Winslow, Arizona. Origin of Meteor Crater Whathappens when an irresistible force meets an immovable object? Meteor Crater!50,000 years ago, a huge iron-nickel meteorite, hurtling at about 40,000 milesper hour, struck the rocky plain of Northern Arizona with an explosive forcegreater than 20 million tons of TNT. The meteorite estimated to have been about150 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. Largeblocks of limestone, some of them, the sizes of small houses were heaved ontothe rim.
Flat-lying beds of rock in the crater walls were overturned infractions of a second and uplifted permanently as much as 150 feet. Today, thecrater is 550 feet deep, and 2. 4 miles in circumference. Twenty football gamescould be played simultaneously on its floor, while more than two millionspectators observed from its sloping sides. In 1902, Daniel Moreau Barringer, aPhiladelphia mining engineer, became interested in the site as a potentialsource for mining iron. He later visited the crater and was convinced that ithad been formed by the impact of a large iron meteorite.
He further assumed thatthis body was buried beneath the crater floor. Barringer was correct. The craterwas formed by a meteorite impact, but what he did not know was that themeteorite underwent total disintegration during impact through vaporization,melting and fragmentation. In 1903, he formed the Standard Iron Company and hadfour placer mining claims filed with the federal Government, thus obtaining thepatents and ownership of the two square miles containing the crater. Barringerspent the next 26 years attempting to find what he believed would be the giantiron meteorite.
Barringer never found what he was looking for, but he dideventually prove to the scientific community that the crater was the site of ameteorite 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 arefixed & immutable. And still worse, there is usually no clue given as to whoclaimed 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 orambiguity of human judgment, no hint of the possibilities of error.
Knowledge ispresented as a commodity to be acquired, never as human struggle to understand,to overcome falsity, to stumble toward the emailprotected -Neil Postman. The End ofEducation Grove Karl Gilbert, the first person to conduct a full scientificsurvey of the mysterious crater in the Arizona desert, was the most renowngeologist of his generation, and has been described as Aperhaps the closestequivalent to a saint that American science has yet produced. (Hoyt, p37) He wastolerant, generous, and fair-minded, with an intense dislike of controversy ofany kind. As chief geologists of the U. S.
Geological Survey, his prestigiousdemeanor was held in high esteem. such that none of his colleagues or successorswere willing to publicly question his conclusions-even when it became apparentthat some of those conclusions had been wrong. In 1891, Gilbert becameinterested in reports of a large collection of nickel-iron meteorites found inthe neighborhood of a gigantic circular crater in the Arizona desert. Since hehad already speculated on the possible consequences of al large meteoritestriking the earth, he decided to visit the crater and try to determine
