Did you know that our planet is a big, spinning magnet?

Or that it is constantly making and remaking its own magnetic field? Or that, right now, there is a titanic battle going on inside the Earth’s molten core as different magnetic factions wage war against each other, striving for dominance?

It’s true. Not only that, but this intimate internal battle is gaining strength and these rearguard cabals are trying to topple the system we have now. When they succeed, the Earth’s two normal magnetic poles – north and south – begin the long trek to switch places. North becomes south. South becomes north. In physics-speak, the planet’s magnetic field changes direction.

The process can take as much as thousands of years. And during that time, the magnetic field wastes away to about a tenth of its usual force, exposing everything on the planet to dangerous solar and cosmic rays.

That could scotch the electromagnetic structure of civilization, putting us back into the equivalent of the Victorian era, technologically speaking. Creatures on Earth will be exposed to more UV radiation and their ability to navigate to find food and mates could be impaired, even highly endangered ones like sea turtles and whales.

Yet hardly anyone on Earth knows that this is afoot.

That’s why I wrote my new book The Spinning Magnet. It tracks the story of how we know all this, including the fantastic findings of the 20th century that proved that the Earth’s magnetic poles have switched places many times and the up-to-the-minute analysis that tells us that our planet’s molten core is in such turmoil right now that the poles may be forced to change places once more.

It’s been breathtaking to research and write.

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Take a look:

“Alanna Mitchell weaves a scientific mystery in the best possible way, exploring the ancient puzzle of our planet’s electromagnetic field, following scientists as they attempt to decipher its clues, leading us to a better understanding of Earth’s invisible and powerful electromagnetic field. The result is a compelling tale of unseen and unforeseen natural forces – and a reminder that we’ve staked our home on a planet that remains infinitely strange, dangerous – and ever full of wonder.” Deborah Blum, author of The Poisoner’s Handbook: Murder and the Birth of Forensic Medicine in Jazz Age New York

“A spellbinding scientific detective story, told over the ages…nimbly explains magnetism’s role in everything that matters. Each chapter is filled with exciting new revelations written in clear, crisp prose. A skilled writer, Mitchell puts magnetism on the map!” Timothy J. Jorgensen, author of Strange Glow: The Story of Radiation

“Alanna Mitchell pulls off the rare trifecta in science writing: an engrossing plot of a planetary mystery, authentic character portraits of scientists and their passion for their work, and explanations of complex physics in easily understandable terms.” Sabine Stanley, professor of Earth and Planetary Sciences at Johns Hopkins University

“The Earth’s magnetic field – an invisible cloak that shields our bodies and our technologies from deadly harm – tends to be taken for granted. In reality it’s a fickle, ill-understood phenomenon… [The Spinning Magnet is] an engrossing book that features a new surprise on every page.” Sean Carroll, author of The Big Picture: On the Origins of Life, Meaning and the Universe Itself

“A fascinating untold story of science that is full of mystery and intrigue, and written with a great deal of style.” Mark Mlodownik, author of Stuff Matters: Exploring the Marvellous Materials That Shape Our Man-Made World