The Dating Game: One Man's Search for the Age of the Earth

Lewis's sketch of Arthur Holmes's (1890-1965) life and work captures a fascinating period of scientific achievement and recovers the accomplishments of a neglected thinker. The young Holmes was enamored of natural history and geology. As an adolescent, he eagerly followed the debates over the age of the Earth between the leading but aged physicist Lord Kelvin and his opponents, much younger scientists using radioactivity for dating. By age 21, Holmes had engaged in numerous experiments, seeking to perfect uranium-lead dating for determining the ages of rocks. Soon he used his research to gauge the Earth's age, and at 23, he wrote a seminal work, The Age of the Earth, in which he argued that the planet was 1.6 billion years old, refuting Kelvin's earlier estimate of 20 million years; later Holmes dated the Earth at 3.35 billion years. Eventually, as a professor of geology at Edinburgh University, he fulfilled his lifelong dream of producing a geological time scale that ordered the temporal ages of the Earth from the Cambrian period to the Pleistocene epoch. In his 1944 (and still used) book, Principles of Physical Geology, Holmes detailed these ideas and also proposed a theory of continental drift that challenged the reigning idea of a onetime land bridge. In due time, Holmes's conclusions about the Earth's age and plate tectonics were accepted into the scientific canon, even though, as Lewis, a British petroleum scientist, argues, he seldom receives credit. Science fans will appreciate Lewis's fast-paced biography tracing the evolution of Holmes's genius, the often hostile and sometimes divisive character of the scientific community and the quest to discover the age of the Earth. 44 illus. (Dec.)