Application of carbon dating in archeology
Thus the less of it that remained in an object, in proportion to normal carbon, the older the object was.
By 1950, Willard Libby and his group at the University of Chicago had worked out ways to measure this proportion precisely.
Some of the carbon-14 might find its way into living creatures.
After a creature's death the isotope would slowly decay away over millennia at a fixed rate.
The prodigious mobilization of science that produced nuclear weapons was so far-reaching that it revolutionized even the study of ancient climates.
He was looking for the carbon that human industry had been emitting by burning fossil fuels, in which all the carbon-14 had long since decayed away.
Comparing the old wood with modern samples, he showed that the fossil carbon could be detected in the modern atmosphere.(5) Through the 1950s and beyond, carbon-14 workers published detailed tables of dates painstakingly derived from samples of a wondrous variety of materials, including charcoal, peat, clamshells, antlers, pine cones, and the stomach contents of an extinct Moa found buried in New Zealand.(6) The measurements were correlated with materials of known dates, such as a well-documented mummy or a log from the roof of an old building (where tree rings gave an accurate count of years).
Their exquisitely sensitive instrumentation was originally developed for studies in entirely different fields including nuclear physics, biomedicine, and detecting fallout from bomb tests.(1) Much of the initial interest in carbon-14 came from archeology, for the isotope could assign dates to Egyptian mummies and the like.
As for still earlier periods, carbon-14 dating excited scientists (including some climate scientists) largely because it might shed light on human evolution the timing of our development as a species, and how climate changes had affected that.(2) It was especially fascinating to discover that our particular species of humans arose something like 100,000 years ago, no doubt deeply influenced by the ice ages.(3) A few scientists noticed that the techniques might also be helpful for the study of climate itself.