The Spinning Magnet

November 20, 2017
Canadian science journalist Mitchell (Sea Sick) investigates critical yet little-discussed concerns for the future of our world in this narrative history of magnetism and study of periodical changes in Earth’s magnetic field. She begins with some giant steps through time to explain magnetism, starting with the big bang and running up to 19th-century Scottish physicist James Clerk Maxwell’s epic mathematical equations that show how electricity, magnetism, and light are all aspects of one another. The historical background is braided with scenes from Mitchell’s quest to find the rocks that French physicist Bernard Brunhes used to prove that Earth’s magnetic poles have periodically switched places. In the latter half of the book, Mitchell examines evidence that the Earth’s magnetic field is weakening—which indicates an upcoming pole shift—and explains the potential effects of such a shift on life around the globe, including electrical grids’ increased vulnerability to solar storms and harm to animals that rely on magnetism for navigation. Mitchell’s nontechnical discussion is substantively accessible, and her vivid writing holds the reader’s attention. Occasionally, elements of the narrative can be hard to follow, and diagrams and figures would have been helpful in clarifying the more complex ideas. Pop science readers and science policy wonks will find plenty to think—and worry—about here. Agent: Ron Eckel, Cooke Agency (Canada).

November 15, 2017
An award-winning Canadian science journalist tells the story of the Earth's magnetic field.Deemed "a fleeting magic" by the ancients, our planet's magnetic force--generated in the Earth's core--holds matter together and makes a giant magnet of the Earth, with north and south poles. With the help of modern scientists, Mitchell (Malignant Metaphor: Confronting Cancer Myths, 2015, etc.) traces our growing understanding of the phenomenon through the "investigations of the Middle Ages, the electrical exploits of the Renaissance, and the compulsions of the Victorians." Leading geophysicists and others walk the author through the lives and experiments of many pioneering scientists, beginning with the 13th-century French engineer Petrus Peregrinus, who first tested the properties of magnetism. Mitchell takes us to an unmarked corner of rural France, where physicist Bernard Brunhes (1867-1910) discovered evidence in a "fabled" piece of rock that Earth's two magnetic poles have often switched places (most recently 780,000 years ago). By 1840, notes the author, 30 permanent observatories were studying magnetism. As she recounts the stories of scientists like Hans Christian Oersted, a Dane who studied the relationship between magnetism and electricity, the Italians Luigi Galvani and Alessandro Volta, Michael Faraday, inventor of the transformer, and seismologist Inge Lehmann, who discovered Earth's inner core, she makes vivid the process of science and the culture of scientific meetings. For all that is known, scientists still do not fully understand "the mysterious goings-on" at the planet's core. We cannot predict when the poles will next reverse, though such a reversal could have devastating impacts in our high-tech, networked world: the magnetic field protects against solar radiation. Mitchell's text sometimes borders on the technical, but patient readers will be rewarded by her combination of thoughtful conversations with, say, the editor of Faraday's papers and her encounters with geophysicist at various conferences.A complex, well-told account of "this spinning magnet we live on."

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December 1, 2017

Journalist Mitchell's (Sea Sick) narrative of progress in our understanding of Earth's electromagnetic field and its patterns is told via biographies of key researchers, including Petrus Peregrinus (13th century), James Clark Ross (19th century), and Inge Lehmann (20th century), among others. The author's journalistic style makes the book accessible to lay readers and is especially evident in her personal descriptions of meetings with French geologist and volcanologist Jacques Kornprobst and Caltech physicist Sean Carroll. Mitchell's simple definitions of terms allow the narrative to flow smoothly; her desire to understand Earth's magnetic system was sparked by seeing the Northern Lights and by her son's organic chemistry curriculum. During her research, she found evidence that Earth's magnetic poles have reversed in the past and will do so again--hence the dramatic subtitle. Some chapter titles are also alarmist, such as "Horrors the Lights Foretold." VERDICT An intriguing story of humankind's recent and evolving understanding of the integral electromagnetic properties of our planet that should hold the interest of both teen and adult readers.--Sara R. Tompson, Jet Propulsion Laboratory Lib., Archives & Records Section, Pasadena, CA

Copyright 2017 Library Journal, LLC Used with permission.

December 1, 2017
Compasses and refrigerator magnets are so common around the world that almost everyone is familiar with the mysterious, invisible force they harness. Yet a deeper understanding of electromagnetism's power and ubiquitous presence throughout the universe has mostly been the province of chemists and astrophysicists. In this captivating scientific history concerning one giant magnet in particular, our spinning Earth, award-winning Canadian journalist Mitchell does her best to make electromagnetism more comprehensible to lay readers. Presented as a guidebook to history's key discoveries about the phenomenon and to the men behind them, Mitchell traces our growing awareness of magnetism, especially its alignment within our planet's core and two poles, from the Middle Ages to modern times. With leading contemporary geologists and researchers providing insights from the sidelines, we meet such scientific pioneers as French physicist Bernard Brunhes, transformer inventor Michael Faraday, and seismologist Inge Lehmann. Mitchell ends on a sobering note, revealing evidence that an imminent magnetic pole reversal could cripple our energy grids. This immersion in magnetism is an invaluable contribution to the popular science shelf.(Reprinted with permission of Booklist, copyright 2017, American Library Association.)