The North Magnetic Pole’s Mysterious Journey Across the Arctic ~ NYT

  • Scientists accelerated the update of a model of Earth’s fluctuating magnetic field, which is needed to keep navigational systems functioning. Many wondered what’s happening inside the planet’s core.
Aurora borealis over Canada, as seen from the International Space Station in 2017. The spectacular display is caused by charged particles from the sun interacting with Earth’s magnetic field. Credit JSC/NASA

By Shannon Hall

 

The north magnetic pole is restless.

Distinct from the geographic North Pole, where all the lines of longitude meet at the top of the world, the magnetic pole is the point that a compass recognizes as north. At the moment, it’s located four degrees south of the geographic North Pole, which lies in the Arctic Ocean at 90 degrees north.

But that wasn’t always the case.

In the mid-19th century, the north magnetic pole floated much further south, roaming around Canada. For the past 150 years, however, the pole has been sprinting away from Canada and toward Siberia.

That change of address cannot be ignored, given that magnetic compasses still underpin modern navigation, from the systems used by civilian and military airplanes to those that orient your iPhone.

In 1965, scientists launched a data-based, mathematical representation of Earth’s magnetic field in order to better keep track of the pole’s ever-changing home. The World Magnetic Model is updated every five years — most recently in 2015 — because the magnetic field is constantly shifting.

In early 2018, it became clear that 2015’s edition was in trouble, because the pole’s Siberian stroll had picked up speed, rendering the model — and therefore a number of navigational systems — incorrect.

So for the first time, scientists have updated the model ahead of schedule, which they released Monday afternoon. Since this work was completed in the wake of the partial government shutdown (which delayed its full release), researchers still are trying to get a handle on the mysteries within Earth’s core that must be driving the magnetic pole’s surprising behavior.

Heading North

The north magnetic pole, the point on the Earth where a compass needle would point down, is sliding about 35 miles closer to Russia each year.

Screen Shot 2019-02-06 at 1.57.45 PM.png

The north magnetic pole’s dizzying dance was first discovered nearly 400 years ago, when Henry Gellibrand, an English mathematician, realized that it had jumped hundreds of miles closer to the geographic pole over the course of 50 years.

“That was a big, monumental recognition that the field was not static, but dynamic,” said Andrew Jackson, a geophysicist at ETH Zurich.

It didn’t take long, however, before magnetic north flipped direction and started to move away from the geographic pole — demonstrating that the field is not just dynamic, it’s unpredictable.

“The problem that we’re still facing today is that we don’t have a good scheme to predict how the field will change,” Dr. Jackson said.

So scientists began tracking the ever-changing magnetic field. The first magnetic maps, which were hand-drawn by exploring sailors, revealed that for the next two centuries, magnetic north twirled among the many islands and channels of the Arctic Archipelago.

Then around 1860, it took a sharp turn and bee-lined toward Siberia. Since then, the pole has traveled nearly 1,500 miles and was most recently found in the middle of the Arctic Ocean, still en route to Russia.

Scientists attribute this wanderlust to the liquid iron sloshing within our planet’s outer core. That iron is buoyant — it rises, cools and then sinks. And that motion below carries Earth’s magnetic field with it, producing changes above.

The north magnetic pole is distinct from the geographic north pole, which is where all the lines of longitude meet at the top of the world. The magnetic pole is the point that compasses recognize as northCredit Norman Kuring, NASA/GSFC/Suomi NPP

To more accurately map those changes, scientists launched the precursor to the World Magnetic Model nearly 55 years ago, which began as a collaboration between the United States and the United Kingdom.

The map we know today has existed in its current form since 1990 and is created by an agency within the National Oceanic and Atmospheric Administration (NOAA) and the British Geological Survey (BGS). It’s commissioned by American and British military agencies, and used by many other militaries across the world.

~~~ CONTINUE  ~~~

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