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Pointing North

April 5, 2019

Pilots at the airport in Wichita, Kansas, will notice some changes this year. All three of the airport’s runways will get new names. Runway 14/32 will become 15/33, for example, while 1 Left/19 Right will become 2 Left/20 Right.

The change is needed because of changes in Earth’s magnetic field. Runways are designated by their compass headings. As the magnetic field changes, though, so do those directions. So the runways need new names to reflect the direction to the north magnetic pole.

And the pole is shifting in a hurry. Since the 1990s, it’s moved an average of about 35 miles per year. It’s moved from northern Canada into the Arctic Ocean, not too far from the geographic pole. It’s headed for Siberia.

Earth’s magnetic field is generated by motions deep within the planet. The outer core is made of liquid iron, which flows as Earth rotates on its axis. That process isn’t smooth and predictable, though. Currents within the core come and go. And blobs of material can move in sudden “jerks” — something that happened a few years ago.

The recent shift is so big that scientists released a new model of Earth’s magnetic field earlier this year — a year earlier than scheduled. The military and other agencies use that model to help navigate around the world. It’s even used in some smartphones. So the early update will help keep many people headed in the right direction — not just pilots.

Script by Damond Benningfield

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