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 Ait@ 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 truth.@ -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 had it
been the result of such an impact. Gilbert=s