Picture of the day - May 8, 2005

Aurora Over Wisconsin

Aurora over Wisconsin
Photo courtesy of Chris VenHaus. 

Today's picture features one of the most beautiful phenomena in nature: an auroral display over the U.S. state of Wisconsin.

An aurora is a faint, yet often spectacular colorful glow in the earth's ionosphere. It occurs when there is an interaction between the earth's magnetic field and the solar wind (charged particles from the sun).


In the northern hemisphere, this phenomenon is called the Aurora Borealis (also known as the Northern Lights), and in the southern hemisphere it is called Aurora Australis (Southern Lights). The auroral displays typically become more pronounced as you get closer to the poles.

Aurora Borealis displays are common in Alaska and northern Canada, but like the one in the photograph above, they can occasionally be seen in many parts of the lower 48 United States.
 

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