Shifting Pole

StarDate

Our planet’s north magnetic pole is on a journey across the top of the world. But it’s slowing down. Over the past five years, it’s put on the brakes – its position has changed much more slowly than over the previous couple of decades.

Earth’s magnetic field acts like a giant bar magnet, with north and south poles. The poles aren’t tied to the geographic poles – they wander.

The north magnetic pole was discovered in 1831. At the time, it was centered over northwestern Canada. It moved farther south, then made a big turn, toward Siberia. In all, it’s moved almost 700 miles since it was discovered.

For a couple of decades, it was moving at more than 30 miles per year. More recently, though, it’s slowed to about 22 miles a year – the biggest slowdown ever recorded. Scientists are trying to understand why.

The magnetic field is generated by motions of molten rock in Earth’s outer core. Those motions produce electric currents, which create the magnetic field. So the changing position and rate of motion are telling us something about what’s going on deep inside our planet.

The change in the magnetic pole has important practical implications as well as scientific ones. GPS, aircraft, the military, and others use magnetic north for navigation. So maps of Earth’s magnetic field are updated every few years to show the change in the pole’s location – keeping everyone headed in the right direction.

Script by Damond Benningfield