Our Magnetic Earth
The Science of Geomagnetism
by Ronald T. Merrill
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Pub. Ed. $25.00
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Our Magnetic Earth
Geomagnetism offers answers to some of the biggest questions about our planet. In Our Magnetic Earth, Ronald Merrill lays out the physics of geomagnetism and magnetic fields before going on to explain how they provide crucial evidence for our understanding of various terrestrial phenomena.
As Merrill explains, we believe Earth’s main magnetic field originates from electric currents flowing in our planet’s iron-rich core, a process that in effect creates a giant dynamo. The term is appropriate, since the phenomenon is dynamic indeed. We learn, for example, that “magnetic north” and “magnetic south” have swapped hemispheres hundreds of times in Earth’s history, and that magnetic north drifted closer to the geographic North Pole by nearly 10 degrees in latitude during the 20th century. To understand why such changes occur, we need a detailed look at our planet’s internal constitution, which Merrill lucidly provides.
There is also an intimate connection between Earth’s magnetism and the Sun; the charged particles known as the solar wind strike Earth’s atmosphere and follow the lines of magnetic force, eventually coming close enough to the planet’s surface to create the northern and southern lights. Earth’s paleomagnetism is also locked into the planet’s rocks, a fact that helped prove the reality of seafloor spreading and continental drift. If you’ve wondered how certain species seem capable of migrating long distances without getting lost, Merrill touches on their abilities to sense Earth’s magnetic field. We even see how geomagnetism may have affected global climate.
Whether you are intrigued by the aurora borealis, magnetic compasses or flocks of birds flying in perfect formation, Our Magnetic Earth is ideal reading.
Hardcover : 272 pages
Publisher: University of Chicago Press ( November 15, 2010 )
Item #: 13-127049
ISBN: 9780226520506
Product Dimensions: 6.0 x 9.0 inches
Product Weight: 21.0 ounces (View shipping rates and policies)
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