12/11/2014:
On this date in 1719, the Northern Lights were first reported in North America. Also called the aurora borealis, they are named for Aurora, the Roman goddess of dawn, and Boreas, the Greek name for the north wind. Galileo named the phenomenon in 1619.
The sweeping waves of color across the night sky are caused by charged particles entering the atmosphere from space. The Northern Lights are more common closer to the magnetic poles. They do occur during the day, but are more visible against a dark night sky. They can sometimes be seen overhead, but are more common towards the horizon nearest the pole. A similar phenomenon occurs in the Southern Hemisphere. It is called aurora australis, or the Southern Lights. There are even auroras on other planets. They have been observed on Jupiter, Saturn, and Neptune.
Auroras are sometimes seen farther south than usual. This generally occurs during a magnetic storm. Auroras are more common during high levels of solar activity, and they are most common in the spring and fall. They are frequently described as curtains of light, and are usually green or red. The red light appears at the highest altitudes. Green lights occur closer to the earth. The lowest altitude of Northern Lights appear blue. These are the least common.
The ancient Norse thought the lights were caused by the Valkyrie as they rode across the sky. The Cree Indians called them “The Dance of the Spirits.” Australian aborigines thought they were campfires in the land of the dead. Benjamin Franklin thought they were caused by electrical charges in the Polar Regions. In the early 1900s, there was a theory that they were caused by solar radiation. Scientists are still not certain exactly what causes them. But there is no doubt that North Dakotans are fortunate to live where there is a good possibility of seeing the lights. It is a spectacular sight, and an experience rarely forgotten.
Dakota Datebook written by Carole Butcher
Sources:
Eather, Robert H. Majestic Lights: The Aurora in Science, History, and the Arts. Washington, D.C.: American Geophysical Union, 1980.
Library of Congress. "http://www.loc.gov/rr/scitech/mysteries/northernlights.html" http://www.loc.gov/rr/scitech/mysteries/northernlights.html Accessed 11 November, 2014.
Space Weather Research Explorer. "http://www.exploratorium.com/spaceweather/auroras.html" http://www.exploratorium.com/spaceweather/auroras.html Accessed 11 November, 2014.