Geology And Geophysics

Magnetic Pole Shift



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In 1831, explorer James Clark Ross discovered the Magnetic North Pole. At the time, it was just above the Arctic Circle, and located in Canada. Then, in 1904, Roald Amundson discovered that the Magnetic North Pole had moved approximately fifty miles closer to the Geographic North Pole during the previous seventy-three years. From this information, and from rock samples taken from ocean floors, we know that the magnetic poles are constantly shifting. However, since that 1904 expedition, the Magnetic North Pole has speed up in it's movements to a speed faster than any other known in history, according to the scientists that study Paleomagmetism (the study of Earth's magnetic past by examining the layers that are found around ocean ridges), who are also studying magnetic minerals at the bottom of Arctic lake beds.

Thanks to paleomagnetism, we now know that the North and South poles reverse completely in an irregular cycle that lasts an average of 300,000 years, leaving magnetic North near the Geographic South Pole and Magnetic South near the Geographic North Pole. Magnetic North and South are only named such because that is the position they were in when the Earth's magnetic field was discovered. At times, the magnetic poles have been much nearer to Earth's Equator than they are now, proving that magnetic North and South have no relation whatsoever to geographic North and South. Earth's last magnetic pole reversal was completed 780,000 years ago, meaning that we are long overdue for another reversal.

So what will happen in a pole reversal? One common misconception is that when the poles shift, the Earth is unprotected from the radiation that comes off of our sun during solar storms will cause catastrophic destruction for that period of time. However, this couldn't be farther from the truth. A magnetic pole shift takes thousands of years to complete, very much slow enough to ensure that the magnetic field will not be distorted enough to allow the destructive potential of the sun to get through.

Most people also believe that the magnetic field stays the same during a pole reversal, just rotating around until it gets to its final position. This is also untrue. While the magnetic field will still be strong enough to block solar storms, it will be greatly distorted and no compasses will work. During the greatest part of the pole shift, there will not even be a truly recognizable magnetic pole.

Remember the magnets that you played with when you were in science class? Place a piece of paper over that magnet and shake some iron filings onto it. The filings will create very regular lines around the magnet. This is what Earth's magnetic field looks like most of the time. now shake the paper just a tiny bit, but not enough to make the filings move too far away from the magnet. This is what Earth's magnetic field looks like during a reversal.

Since the most recent pole reversal (780,000 years ago), the magnetic poles have been moving at a rate of less that 10 miles per year, usually in an irregular circle around the geographical poles. Since the Magnetic North Pole was discovered, the rate of shift has sped up immensely and the poles have started to move closer to their geographic counterparts. The poles currently move about 25 miles per year. Since its discovery in 1831, the Magnetic North Pole has shifted 700 miles and is no longer in the country of Canada, it is currently located much farther north at the edge of the arctic waters that Canada claims. It is estimated that the Magnetic North Pole will be in Siberia by 2050 if the pole continues it's present course and speed.

Since 1948, the Canadian government has kept track of where the Magnetic North Pole is by conducting routine surveys once every 10 years. However, the scientists that go on these expeditions say that the surveys will have to be done more often now that the pole is moving faster.

Earth's magnetic field is created by the core of the Earth, which has two layers. The inner layer of the core is solid, while the outer layer is liquid iron. These two layers move and rotate independently of the mantle and crust of the Earth, which is why the magnetic field created by this movement moves independently of the exterior of the Earth.

The independent movement of this core also causes changes in the intensity of the magnetic field. Since the 1800's, the intensity of Earth's magnetic field has dropped a full 10 percent, promoting many people to worry about a collapse of Earth's magnetic field and giving people another theory regarding past mass extinctions. Paleomagnetism has shown that the magnetic field has been much weaker several times in the past, none of these times coinciding with a mass extinction.

The magnetic pole shift is causing and will cause some strange effect on the Earth. Every decade, compasses near the Equator point about one degree different that those of the decade before. By 2050, Russians and Siberians will be able to see the Aurora Borealis better than Canadians and Alaskans. And one day, people near the Equator will be able to see effects in the sky that are very similar to the Aurora Borealis.

The current pole shift may be the very beginnings of a complete pole reversal, though those of us living now will never know for sure, only a lot of time will be able to tell if it is or is not one. 100 years ago, these changes we are experiencing even now would have been catastrophic for navigators, because they only had a compass to point the way, but thanks to our new technology of GPS (global positioning satellite), we will be able to navigate with ease throughout the entire magnetic change.

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