Nature's Clocks : How Scientists Measure the Age of Almost Everything

"Radioactivity is like a clock that never needs adjusting," writes Doug Macdougall. "It would be hard to design a more reliable timekeeper." InNature's Clocks,Macdougall tells the fascinating story of scientists seeking to understand the past and shows how they arrived at the ingenious techniques they use to determine the age of objects and organisms. By examining radiocarbon (C-14) dating--the best known of these methods and the only one that can directly date once--living material-and several other techniques that geologists use to decode the distant past, Macdougall unwraps the past century's advances, explaining how they reveal the age of our fossil ancestors such as "Lucy," the timing of the dinosaurs' extinction, and the precise ages of tiny mineral grains that date from the beginning of the Earth's history. In lively and accessible prose, he describes how the science of geochronology has developed and flourished. Relating these advances through the stories of the scientists themselves, Macdougall shows how such major figures as James Hutton, William Smith, Arthur Holmes, Ernest Rutherford, Willard Libby, and Clair Patterson used ingenuity and inspiration to construct one of modern science's most significant accomplishments: a timescale for the Earth and all its creatures.

Doug Macdougall is Professor Emeritus of Geosciences at Scripps Institution of Oceanography, University of California, San Diego.