History
The asteroid fell about 50,000 years ago. The meteorites have been known and collected since the mid-19th century and were known and used by pre-historic Native Americans. The Barringer Crater, from the late 19th to the mid-20th century, was the center of a long dispute over the origin of craters that showed little evidence of volcanism. That debate was settled in the 1950s thanks to Eugene Shoemaker's study of the crater.
In 1953, Clair Cameron Patterson measured ratios of the lead isotopes in samples of the meteorite. The result permitted a refinement of the estimate of the age of the Earth to 4.550 billion years (± 70 million years).
Read more about this topic: Canyon Diablo (meteorite)
Famous quotes containing the word history:
“The history of progress is written in the blood of men and women who have dared to espouse an unpopular cause, as, for instance, the black man’s right to his body, or woman’s right to her soul.”
—Emma Goldman (1869–1940)
“The history of reform is always identical; it is the comparison of the idea with the fact. Our modes of living are not agreeable to our imagination. We suspect they are unworthy. We arraign our daily employments.”
—Ralph Waldo Emerson (1803–1882)
“History takes time.... History makes memory.”
—Gertrude Stein (1874–1946)