North Pole

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Alert the elves and reindeer: the North Pole is moving! Actually, the North Pole is always on the move. And just to confuse you more, there are actually two poles, and neither of them ever stay still. The magnetic North Pole, though, is the one to worry about at the moment.

Our protective bubble

The magnetic North Pole is created by the magnetic field that surrounds and protects the Earth from harmful solar winds. It’s that magnetic field that helps determine where your compass points. Think of the Earth as a giant round magnet with a positive and negative end. If you’ve ever played with magnets, you know that the positive end of one will only be attracted to the negative end of another. A traditional compass works on the same basic principle. The magnet inside a compass is attracted to one end of the giant magnet that is the Earth. So it points you in the direction of north no matter where you might be on the globe. We normally think of this spot as somewhere near the “top” of the planet.

Shifting forces

But over the last century, “north” has been moving north at the rate of about 30 miles a year. Obviously, this creates some problems for hikers. It creates even more headaches for the military not to mention the transportation industry. Planes, missiles — these things operate based on pinpoint accuracy, accuracy determined by GPS coordinates. But when the magnetic pole moves, GPS coordinates are scrambled, so much so that the U.S. military has this year asked the National Oceanic and Atmospheric Administration to update their model. The NOAA, which tracks the pole and maintains the World Magnetic Model on which GPS systems are based, normally updates every five years but this request came early.

Alarming “jerks”

According to geologists, the Earth’s magnetic field is caused by iron and nickel deposits in the Earth’s outer core, some 1800 miles beneath the surface. These seas of liquid metal are constantly in motion, interacting with one another and consequently altering the polarity of the magnetic field. That’s all well and good; most of the time changes to these seas occur slowly. However, they can also occur spasmodically, a bit like earthquakes.

In a recent study two scientists, Julien Aubert and Christopher Finlay, fed four million hours worth of data into a supercomputer to try and determine just how these sudden changes occur. As they explain, gradual movements occur because the Earth’s core emits heat at a rate of six miles per year. As the heat reaches the outer core it alters the iron and nickel that control the magnetosphere. However, occasionally pockets of liquid iron in the core are significantly hotter than the material around them. These rise quickly to the surface, causing a sudden “jerk” in the magnetic field. Aubert describes these as similar to “vibrating strings of a musical instrument.”

Our ever-changing world

These jerks have led some doomsayers to argue that we are close to a total pole reversal, in which the North and South Poles would switch places. Such an event does seem to occur to the Earth at regular intervals, around a million years or so apart. And they can be destructive. However, dire predictions that the magnetic field might suddenly disappear, leaving the entire Earth completely vulnerable to deadly radiation, are unlikely. The last time the poles switched, some 750,000 years ago, the result was a temporary reduction of only about 30% in the field.

While we may not be in for a catastrophic polar change, the movement of the North Pole is definitely having a pronounced effect on one of Earth’s wonders. At the rate of 30 miles a year, it is likely that the Northern Lights, a product of the magnetic field, will be shifting as well. In fact, many scientists suggest it may soon be most visible over Siberia.