Tracking the Aurora Borealis

University of Alaska physics professor Roger Smith explains the northern lights—and when and where to see them.

Physics professor Roger Smith, University of Alaska, Fairbanks, Alaska, image

Professor Roger Smith helps forecast aurora displays.

Knowing the science behind the aurora borealis—the nighttime phenomenon dubbed the northern lights—only enhances their beauty. When the lights shimmer above Fairbanks, University of Alaska physics professor Roger Smith is as enthralled by the spectacle as anyone.

Q What causes auroras?
A
Auroras light up when streams of particles from the sun—solar winds—collide with electrons and protons in the earth’s magnetic fields. The collisions happen 60 to 200 miles above the earth’s surface. Auroras are constantly forming at the poles, but you can’t always see them.

Q Will auroras show up in the lower 48 this year?
A
Definitely. The sun is flaring right now, which means bigger and brighter auroras will reach farther south. In the coming year, northern Montana and Idaho might have auroras as often as one night out of 10. On those nights, the view outside Great Falls or Coeur d’Alene can be more spectacular than it is in Alaska.

Q When’s the best time to see auroras?
A
In the lower 48, the season doesn’t matter much. But you need a clear, dark night and a northerly view. Auroras shine brightest within an hour or so of midnight.

Q Any way to predict where and when auroras will appear?
A
Scientists rank the level of auroras’ activity from 0 to 9. A ranking of 5 means they should be visible below the Canadian border. If the ranking hits 9, Southern California might be in for a show. As for when to watch for them, check out the aurora forecast on the website of the Geophysical Institute at the University of Alaska-Fairbanks (gi.alaska.edu).

Q Is it possible to hear auroras?
A
I’ve never heard one. Auroras haven’t been proven to make sounds audible at ground level, but they do release radio waves. Who knows? Some people might be able to pick up that signal.

Photography by UAF Photo/Todd Paris

This article was first published in March 2013. Some facts may have aged gracelessly. Please call ahead to verify information.

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