Science

  • Issue 111 / May - June 2016



    Should We Fear a Magnetic Pole Shift?

    Serif Dogru

    The Earth currently rotates in a counter-clockwise direction. This rotation, along with movement of iron particles inside the Earth’s molten core, generates a magnetic field, which protects the Earth from solar winds. Since this magnetic field is determined by using the right-hand rule, its direction is from the magnetic North Pole (the geographic South Pole) towards the magnetic South Pole (the geographic North Pole).
    Yet, some scientists believe this “order” might be about to change. Research shows the positions of the magnetic poles shifting, with the magnetic north- and south poles moving at a rate of 10 miles per year – and they’re moving towards each other. Simultaneously, the strength of Earth’s magnetic field is rapidly decreasing. This decrease is growing faster – it has weakened 15% in the last 200 years. These two facts suggest that the Earth’s magnetic poles could be preparing to reverse. In fact, the process has already started, and a magnetic pole reversal may happen over the course of a few hundred years.



    At first glance, it sounds frightening that the Earth’s magnetic poles are about to shift. But when we study geologic history, we’ll see that such a shift has happened before – many times. When scientists study the direction of the Earth’s core, it suggests that all sediment cores must have the same direction. But research shows that some sediment cores from the deepest parts of the ocean have the opposite direction. This helped scientists confirm that magnetic pole reversal is a natural event which happens, approximately, every half a million years. Since the last one occurred 780,000 years ago (the Brunhes-Matuyama reversal), the Earth is overdue for another reversal.


    Some scientists say that this upcoming reversal will be drastic. During a magnetic pole reversal, solar winds could punch holes in the ozone layer. This could damage power grids, and affect cancer rates and the climate. The aurora borealis, normally only visible in the extreme northern hemisphere, would be visible every night all over the world.


    Such a magnetic pole shift is a physical rule, not the exception. Each reversal happens over hundreds or thousands of years; it is not a clean flip. Magnetic fields morph and push and pull at one another, with multiple poles emerging at odd latitudes throughout the process. Scientists estimate reversals have happened hundreds of times over the past three billion years. And while reversals have happened more frequently in "recent" years, when dinosaurs walked the Earth, a reversal was more likely to happen only once every one million years.


    Many conspiracy theorists like to claim that a magnetic pole shift will mean doomsday. But according to scientists who have studied geologic history, such a pole shift is nothing to fear, as it has happened hundreds of times throughout the Earth’s history. Though it could mean big changes for human civilization, we cannot be absolutely sure whether it will be the end of the Earth or not.


     


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