(The Spinning Magnet, Alanna Mitchell, January 2018)
The Ultimate lose-Lose Proposition
With all the talk of climate change, the sixth extinction, the collision of galaxies and the death of the sun, Alanna Mitchell adds another – the fading of our magnetic field. We are protected from the sun’s ferocity by a magnetic field that comes from the core of the planet. The sun can blow it back, but it can’t blow it away. Worryingly, all is not well with that shield.
The Spinning Magnet is almost entirely history. Mitchell looks at the long list of milestones as we discovered and tried to understand electricity and magnetism. There are as many wrong turns as right ones, but today we have a good idea of what came before (though no feel for what comes next). The most important discovery was that electricity and magnetism are both manifestations of the same force. We ignore one for the other at our peril. By 1838 we knew the magnetic field came from the center of the Earth. We’ve spend the following 200 years taking measurements everywhere, all the time, to figure out the patterns, the intensity, the movements and the implications. But that’s also how we know it is fading.
The magnetic north and south poles used to reverse fairly regularly, and they leave traces when they do. There hasn’t been one since we came along, so we don’t know what to expect. But reversing the poles and the field will almost certainly wreak havoc like we’ve never seen. For one thing, we now run on electricity. When extraordinary solar flares penetrated the field in the mid 1800s, batteries powering the telegraph network all over the western world caught fire, seemingly spontaneously. Disconnecting them did not shut the system down, however. It ran on “celestial power”. Today, everything is electric. But in addition, everything runs on magnetic media. All the software, hard drives and memory banks in the world might be wiped if the magnetic field behaves badly. It could be like Puerto Rico after Hurricane Maria, but with no possibility of aid, as nothing would work anywhere. And that doesn’t count what it might do living beings. Birds for example, can actually see the magnetic field, and use it to navigate thousands of miles twice a year. Many insects use it too. We have no idea how they will handle a reversal. If the field doesn’t reverse but fades away, the sun will be free to fry the Earth into another Mercury, and continually bombard it with killer radiation (which is why “escaping” to Mars is no solution. Its magnetic field is long gone). It gives one pause.
Mitchell’s style is fast and spare. Her book is very easy to read. The sentences are short, direct and declarative. The chapters are short and concise. They are discrete entities, each having its own tight purpose. She avoids the worst complexities. It is page 96 before Mitchell uses the word quantum. And it only appears once more later. That’s pretty remarkable for a book on atomic structures and processes.
The irony is that our discovery of electricity, magnetism and how to employ them has allowed us to understand that life as we know it could end with the change or demise of the magnetic field and all the wonderful ways we have deployed electricity and magnetism.
David Wineberg