Naked Earth: The New Geophysics
by Shawna Vogel
Dutton/Penguin
Everybody knows about plate tectonics—that the Earth's crust is cracked into chunks that slide slowly around its surface, ferrying the continents with them in an endless demolition derby. Shawna Vogel, author of Naked Earth, says it's the one fact about Earth science that the majority of adults know. Plate tectonics was the first successful theory of global geology, and as all great theories do, it opened a tempting vista of deeper scientific questions to ask and new problems to solve.
Naked Earth: The New Geophysics is a panoramic survey of that new vista. In many respects plate tectonics has closed the books on traditional geology, but in the thirty years since its acceptance the major questions of geophysics have remained. What is the Earth's core composed of? How is the geomagnetic field maintained, and why does it reverse its direction many times over the course of geologic time? What is the structure of the rocky mantle, which makes up the majority of the planet's mass? And how do these different phenomena fit together with the crustal plates in a unified Earth system?
For the past 40 years, geophysicists have been closing in on a great prize—a complete physical and chemical description of the planet from its cool surface rocks to its fiery metal heart. This has been a riveting story, but only people in or near the scientific life have known about it, and almost no one has known about it all. Whereas plate tectonics was about the obvious, deep-Earth geophysics is about the invisible, and the methods of geophysics are abstract and mathematical. The cast of characters includes seismologists, geochemists, high-pressure experimentalists and mathematicians, to name just a few.
To tell this story, Vogel relies on the craft she learned as an editor at Discovery magazine. The Lava Lamp, cream on top of oatmeal, dregs in salad dressing and other lively analogies dot every page, and many notable scientists are brought to life in interviews. As a result, there is no more accessible treatment of modern deep-earth science in print. Nevertheless, Naked Earth is not for the casual reader—it packs more science into its 200 pages than most Americans will read in a lifetime.
The Earth-science professional will read this book with pleasure, for Vogel gets things right. She captures a sense of the humanity behind the science, and she covers all the bases that can be covered without using any mathematical expressions. Deeper understanding is not part of her program. The equation of state, for example, perhaps the single most important concept in mantle studies, is not mentioned. Nor are any publications referenced or graphs presented. Naked Earth is a very good show, suitable as a general survey of the field, but it will not get you behind the curtain. She catches the outlines of the action, a formidable achievement in itself, and shines welcome light on the great collegial work of understanding Earth in depth.
