cover image A Natural History of Time

A Natural History of Time

Pascal Richet, . . Univ. of Chicago, $29 (471pp) ISBN 978-0-226-71287-1

For millennia humans relied on mythical or biblical accounts to conjure up a birth date for our planet. Astronomer Edmund Halley used the amount of salt in the oceans as his calendar. The great Newton ventured at writing a chronology that took most of the stories of Greek kings and heroes at face value. But as French geophysicist Richet tells readers, people didn't get serious about ascertaining the age of the Earth until the Enlightenment, when researchers tried to figure the amount of heat lost by the Earth to reckon backward to its molten youth. But a firm date—4.5 billion years—couldn't be established until the discovery of radioactive elements to date everything from textiles to stones. Richet writes in a meandering European style as he draws in figures from other fields (who would have guessed that Voltaire was Newton's principal advocate on the Continent?) to fill out his story. His writing occasionally plods along, and attempts at humor sometimes fall flat, although these may be just hazards of translation. Geology and natural science buffs will discover a rich, baroquely embellished birthday cake to dig into and enjoy. 12 half-tones, 27 line drawings. (Aug.)