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By Kenny Taylor



Splashing the sky with radiant hues, auroras can crash power grids and satellite systems even as they delight scientists and spectators with their glowing gases.



Get a taste of what awaits you in print from this compelling excerpt.

The whole dome of night sky was awash with color: cascades of yellow-green and blushes of crimson fanning from a darker point high overhead. As they fell in broad rays, they shifted and changed in brightness, sometimes intense in one place, then cool, then hot. It was like looking up into the heart of a flower of glorious light whose petals rippled in a breeze that could not be felt—a breath from beyond this planet.

That aurora (Latin for “dawn”) lit up the night at my home in the Scottish Highlands more than a decade ago, but to this day I can picture its colors, shapes, and movements. The show peaked for less than an hour, but its tonal themes lingered longer. It seemed an act of magic, but I knew that science had unveiled this magic act: Electrically charged particles from the sun were making gases glow in the upper atmosphere.

Thousands of miles away, in Alaska, the aurora also caught the attention of Charles Deehr, a physicist at the Geophysical Institute of the University of Alaska Fairbanks. “That display on March 13-14, 1989, was one of the best in the last 50 years,” he said.

I visited Deehr in March 2001 during the current phase of intense auroral activity. Deehr is a wiry man who retains, in his sixties, a youthful zest for new research ventures. His work in auroral forecasting mixes science and divination as he searches for patterns in the latest information sent from near-Earth satellites in hopes of predicting auroral activity a day or so in advance. Such forewarning makes it possible to prepare electrical systems on Earth and in space for disturbances.

Scientists use satellites to gauge an aurora’s power, but it was the 1989 aurora’s extreme reach that demonstrated to most of us how unusual it was. Most auroras are visible only in the higher latitudes (above 60 degrees), but that one showed up as far south as Key West in Florida and the Yucatán Peninsula in Mexico. People unnerved by the Şery tint in the sky phoned the police; others watched in awe. Within 90 seconds of the aurora’s reaching the skies above Quebec, magnetic storms associated with it caused a province-wide collapse of the power grid, leaving six million Canadians without electricity for hours.

At the same time, compass readings became unreliable, and there were reports of automatic garage doors opening and closing on their own. Radio transmissions and coastal navigation systems were disrupted, and information feeds from some satellites were temporarily lost.

Get the whole story in the pages of National Geographic magazine.






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In More to Explore the National Geographic magazine team shares some of its best sources and other information. Special thanks to the Research Division.


Reports of audible auroras come as a surprise to many, but the people of northern Europe and North America have long told of hissing or crackling sounds that occasionally accompany the show. Although rare, auroral sound seems to be a real phenomenon. The sounds reported are similar whether the reporter is a trained auroral scientist or just a tourist watching the lights, but attempts to make acoustic recordings have not been successful. Like much about the aurora, the cause of the sounds is unknown, and its infrequency makes it difficult to investigate. The Department of Physics and Astronomy at the University of Calgary, Alberta, presents a summary of likely and unlikely theories, along with links and a bibliography, at www.phys.ucalgary.ca/satellites/html/aur_sound.html. Scientists need to be skeptics, but sometimes ordinary experiences can cause them to change their minds. What follows is an account from Charles Deehr, a scientist who has spent decades in Alaska studying the aurora.

“There have been a number of anecdotal observations of auroral sound. There is a section on it in every book on the aurora, and there have been some scholarly investigations and reviews. I never thought any of it was believable.

Then on November 8, 1998, I happened to be outside in the Goldstream Valley when there was no wind, and only a couple of cars in the valley. I heard some soft static sort of sound, which seemed to be associated with some fast-moving green-white rayed bands of light. Unfortunately, there was background noise and I had to close my eyes to hear, so it was not a clear case of auroral sound. Later that evening when I walked up the hill to feed the neighbor’s dogs, I heard it again. This time there were no cars in the valley, and it was clearer, but I still found it necessary to close my eyes to hear it well. I’m a believer.”

—Patricia B. Kellogg


International Solar-Terrestrial Physics
www-istp.gsfc.nasa.gov/
Explore the sun-Earth connection through NASA’s ISTP website. This resource offers beautifully illustrated Web pages for every level of expertise. Some material is available in Spanish with links to Latin American resources.

Space Weather Now
www.sec.noaa.gov/SWN/index.html
In addition to producing weather reports for Earth, the National Oceanic and Atmospheric Administration now produces space weather reports. You will find images of the sun with close-ups of today’s active spots, warnings of geomagnetic storms, and tips on watching auroras.

Aurora’s Northern Lights
climate.gi.alaska.edu/Curtis/curtis.html
This site, from aurora photographer Jan Curtis, offers aurora photos and video clips from around the world. Curtis has assembled dozens of links to academic and nonacademic sites.

Poker Flat Research Range
www.pfrr.alaska.edu/INDEX.HTM
Poker Flat Research Range, a rocket-launching facility operated by the University of Alaska’s Geophysical Institute, has assembled photos, videos, scientific material, and even a daily aurora forecast for anywhere in the Northern Hemisphere.

Cary Anderson
www.caryanderson.com
This site, by aurora photographer Cary Anderson, features images of the aurora borealis and American wildlife from the far north and southwest. To contact Anderson, e-mail him at caryak@alaska.net.

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Bone, Neil. The Aurora: Sun-Earth Interactions. Ellis Horwood, 1991.

Davis, Neil. The Aurora Watchers Handbook. University of Alaska Press, 1992.

Eather, Robert H. Majestic Lights: The Aurora in Science, History, and the Arts. American Geophysical Union, 1979.

Savage, Candace. Aurora: the Mysterious Northern Lights. Sierra Club Books, 1994.

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“Those Mysterious Lights in the Sky,” World (December 1987), 18-23.

O’Neill, Catherine. Amazing Mysteries of the World, National Geographic Books, 1983.

Gartlein, Carl W. “Unlocking Secrets of the Northern Lights,” National Geographic (November 1947, 673-704.

Grosvenor, Gilbert Hovey. “The Mystery of Auroras: National Geographic Society and Cornell University Study Spectacular Displays in the Heavens,” National Geographic (May 1939), 689-690.

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