30 No. 6
Libby and the Nuclear Hourglass
Radiocarbon dating is one of the most important radiometric methods available to estimate the age of carbon-containing materials up to 60 000 years old, and has thus found multiple applications in archeology, geology, and other branches of science. It is based on the use of the naturally occurring carbon-14 radioisotope, which is continuously generated in the stratosphere and upper layers of the troposphere when cosmic rays interact with atomic nitrogen. This nuclide is quickly oxidized to carbon dioxide and enters the global carbon cycle, where it slowly begins its unrelenting beta decay to nitrogen-14 with a half-life of about 5 730 years.
The stamp illustrated in this note was issued by Monaco in 2004 to honor Willard Frank Libby (1908–1980), the American chemist who developed the technique of radiocarbon dating in the late 1940s while working at the University of Chicago. He subsequently received the 1960 Nobel Prize in Chemistry for this discovery. In addition to Libby’s likeness, the stamp shows an hourglass, a clever choice since the radioactive decay of carbon-14 occurs at a regular and predictable rate, much like the flow of sand in an hourglass. Unfortunately, it is also worth noting that the stamp incorrectly gives Libby’s first and middle names as Frank Willard (instead of Willard Frank), not the first time the wealthy city-state makes a blunder in the realm of chemical philately, as we shall see in a future note.
Written by Daniel Rabinovich <[email protected]>.
last modified 7 November 2008.
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