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Benchmarks: Henri Becquerel discovers radioactivity on February 26, 1896

February 26, 1896, was an overcast day in Paris — and that presented a problem for French physicist Antoine Henri Becquerel. Becquerel was hoping to demonstrate a link between minerals that glow when exposed to strong light and a new type of electromagnetic radiation called X-rays. The weather thwarted this experiment — but that failure inadvertently produced an entirely new discovery: natural radioactivity.

28 Feb 2011

Benchmarks: May 18, 1952: Stonehenge's age solved with Carbon-14

Like sentinels standing guard over a millennia-old secret, the 8-meter-tall stones of Stonehenge rise above the rolling green hills of England’s Salisbury Plain. The origin, date and purpose of the arrangement of the giant standing stones, located about 145 kilometers west of London, have puzzled people for thousands of years. But in 1952, physical chemist Willard Libby, a professor at the University of Chicago in Illinois, finally provided a concrete answer to one of the site’s most enduring questions: when it was built. To do this, Libby used a brand-new geochemical technique that he had been developing based on the radioactive isotope carbon-14. Only a few years later, his work on this groundbreaking technique earned him a Nobel Prize for Chemistry.

18 May 2010

Nuclear Fallout

Willard Libby, who won a Nobel Prize for Chemistry in 1960, was a prominent advocate of nuclear weapons testing, and worked on the Manhattan Project to help develop an atomic bomb during World War II. During the late 1950s, chemist Linus Pauling, a peace activist who won Nobel Prizes for both Chemistry and Peace, presented the United Nations with a petition signed by more than 11,000 scientists that called for an end to nuclear weapons testing. In particular, Pauling cited a 1958 speech on carbon-14 by Libby that suggested nuclear tests would produce large amounts of the radioactive isotope. 
18 May 2010