The North Pole ain’t what it used to be. Well, the geographic North Pole stays fixed over time (mostly because we define it to stay fixed over time) but the magnetic north pole constantly moves. And over the past decade it’s been moving out of Canada towards Siberia four times faster than it has in the past couple centuries. Armed with data from the ESA’s Swarm satellite, scientists might finally know why: the shifting of our magnetic field north pole is caused by a titanic struggle between two competing massive magnetic plumes.
Even though the Earth’s magnetic field looks just like a bar magnet, with two poles on either end, the way it’s generated is much more complex. Deep inside the Earth, the outer layers of our core are liquid molten iron. That iron spins rapidly, carrying its electric charges in frenzied circles over and over again. Moving electric charges generate an electric current, and any little changes in that electric current amplify, folding over on themselves and generating a magnetic field – one of the strongest magnetic fields in the solar system, capable of puncturing the surface of the Earth itself and extending thousands of miles into space.
Those magnetic field lines leave the Earth at the geographic South Pole (confusingly enough, what we call the “South Pole” is really the magnetic north pole, but that’s a different story), and curve and arc their way northwards before plunging back into the Earth’s crust in northern Canada.
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Because our magnetic field is caused by the chaotic twisting and tangling of the electric current of iron in our core, the magnetic field constantly shifts its shape and position over the years. This is been known since we first began measuring it in the early 1800s, but the cause of the recent surge in movement of magnetic north has been a mystery.
Thankfully, the ESA’s Swarm mission, which has been mapping the details of the Earth’s magnetic field, may give us some clues. It appears that the location of the north magnetic pole is determined by the balancing act of two massive magnetic regions plunging into the Earth right next to each other. And one of those blobs seems to be weakening, allowing the other one dominate, pushing the magnetic field towards Siberia.
As far as the researchers can tell, this motion will continue for at least another decade, but with the complexities of the Earth’s core, it’s impossible to tell what will happen after that. The north magnetic pole may return to its Canadian home, or it might permanently immigrate to the remote reaches of Eastern Russia.
No matter what, we need to carefully track of the movement of magnetic north. Navigation systems around the world, including the cell phone that’s probably in your hand right now, rely on compasses to aid in navigation, along with GPS systems. And if they get the location of magnetic north wrong, well you’re never quite sure exactly where you are.
Precise location tracking requires knowing the details of our Earth’s magnetic field changes year-to-year, and this rapid shift in magnetic north is forcing us to revise our maps faster than we expected – and the new understanding helps us better predict where north might be in the future.