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Scientist Say They Now Know How an Aurora Occurs

A group of physicists re-created the wave that causes the northern lights
By Liz MacGahan,  Newser Staff
Posted Jun 12, 2021 11:03 AM CDT

(Newser) – Physicists say they know how the awe-inspiring aurora borealis light shows are formed and can for the first time prove it in a lab. It all has to do with surfing and waves. Electrons traveling to Earth can catch waves, called Alfvén waves, which pick them up and throw them at our planet much faster—think 45mph. Those electrons hit the atmosphere, and when everything settles down, an aurora blossoms, resulting in what we know as the northern lights. This has been the assumption for decades, first suggested by Soviet scientist Lev Landau, but now it has been measured, NPR reports. Researchers from the University of Iowa, Wheaton College, and UCLA used something called a Large Plasma Device to prove electrons can hitch rides on Alfvén waves.

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They used an antenna to start a wave, “much like shaking a garden hose up and down quickly, and watching the wave travel along the hose, Iowa’s Greg Howes said, per CNN. Then, the scientists observed electrons catching a ride on that wave, and gaining energy. "Think about surfing," says Wheaton's Jim Schroeder, lead author of the paper in Nature Communications. "In order to surf, you need to paddle up to the right speed for an ocean wave to pick you up and accelerate you, and we found that electrons were surfing. If they were moving with the right speed relative to the wave, they would get picked up and accelerated." Scientists didn’t get to see the full effect—they just proved the wave theory works but did not create a light show. And while this might someday help predict the appearance of an aurora, that, too, is a long way off. (Read more aurora borealis stories.)

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