The Northern Lights: What Are They? The aurora borealis has fascinated people for hundreds of years. These “northern lights” are beautiful displays that brighten the night sky in the far north with glowing arcs, clouds, and streaks. These can be red, purple, or green, and may go on for thousands of miles across the horizon. Though the borealis has always been regarded with awe and wonder, it was not always known what causes these displays. We now know that the northern lights are astronomical phenomena caused by solar wind, the flow of charged particles from the surface of the sun. Some of these particles get trapped in the Earth’s magnetic field and release energy that causes visible auroras.
Early Exploration of the Northern Lights
Since ancient times, there has been folklore associated with the aurora borealis. These stories came largely from the native people of Finland, Norway, and other places where the aurora is typically visible. In Finnish, the term for the aurora translates to “fox fires”, believed to be the result of a magical fox brushing snow into the air with its tail. Those in Lapland believed these “fires” were the souls of the dead.. In Norway, the aurora was said to be the spirits of old women dancing. A scientific explanation for the lights was somewhat longer in coming. Beginning around 1895, the Norwegian physicist Kristian Birkeland sought to discover why the aurora is seen mainly in polar regions. His experiments were based on his hypothesis that the aurora’s particles came from the sun. His work helped substantiate that the magnetic fields of the Earth were largely responsible for the way the auroras appeared. Later, fellow Norwegian scientists Lars Vegard and Carl Størmer added to his body of work. Vegard was the first to map the colors of the auroras, while Størmer calculated the existence of a “belt-like” zone around the Earth where charged particles moved between the poles. His beliefs were verified with the discovery of the Van Allen Belt in 1958.
More Facts About Northern Lights Becoming Clear
Over time, researchers have learned more about the aurora borealis. Recent research has uncovered, for example, the reason why the northern lights may suddenly seem to brighten and “dance.” This is due to the sudden reconnection of magnetic fields in an area of space about one-sixth of the way to the moon, which releases a large amount of energy. Likewise, it is now known that the prevalence of the aurora borealis is linked to the electromagnetic activity of the sun, which intensifies and wanes on an eleven-year cycle. More auroras are likely during the solar maximum period of intense radiation. Auroras are most often seen in Alaska, Canada, and Scandinavia, but in times of extreme solar activity they may also be seen in parts of the U.S. and Europe. Recently, researchers have also re-examined the ancient idea that climate and the aurora are linked. Though the aurora has no bearing on weather conditions such as rain and wind, it is suspected that colder average temperatures on the Earth’s surface may be correlated with dips in solar activity, and higher temperatures with spikes that would produce more auroras. As research continues, scientists are sure to learn more about the aurora borealis and what this beautiful phenomena can teach about the Earth, the sun, and the solar system.
For more on the aurora borealis, please see the following links:
NASA: Aurora: NASA’s official page with a brief overview of the aurora and the mechanism behind it.
Aurora Borealis: Northern Lights: Capsule discussion of the aurora with tips on viewing them.
Maryland Geological Survey: Aurora Borealis: Detailed information on the role of the sun in causing auroras, with an index of verified resources for finding out more.
The Northern Lights: Resources on understanding auroras, finding them, and viewing them. Includes links to a number of high-quality photo galleries showing auroras in action.
The Northern Lights in Mythology and Folklore: Overview of folklore and fantastic tales about the auroras, including a selection of beliefs from Scandinavia, the ancient Mediterranean, and the indigenous people of North America, among others.
The Norwegian Space Center: Aurora Borealis: Discusses the history of scientific research into the aurora, with further information on the three Norwegian scientists whose breakthroughs helped shape modern understanding of the “lights.”
The Norwegian Aurora Polaris Expedition, 1902 – 1903: (PDF Document) Digitized full-text version of a narrative describing a research-oriented voyage to explore the cause of the aurora borealis. Includes a huge amount of then-current scientific information. Translated from the Norwegian original written by Kristian Birkeland.
Polar Cap: History: Detailed website including concepts and histories relating to the scientific exploration of the aurora borealis.
Aurora FAQ: Detailed answers to common questions about the aurora borealis, provided by the Geophysical Institute of the University of Alaska.