What Is St. Elmo's Fire?

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By By Steve Pool

SEATTLE - It's one of nature's more eerie sights. It's a blue or green glow around pointed objects that's caused by electric fields. It's a semi-rare event, and is most common during strong thunderstorms.

The aura usually forms on the tall points -- such as power poles, ship lasts, antennas, or even aircraft wings -- where electric charges are building in advance of a lightning strike. The glow comes from the tiny sparks of positive charges reaching skyward toward a growing area of negative charges in the sky or in the base of a thunderstorm's cloud.

It was named after Saint Elmo -- the patron saint of sailors. This phenomenon was first observed off the masts of ships hundreds of years ago. It was believed to be mentioned in Moby Dick, as well as Shakespear's "The Tempest".

For More Information:

www.physics.northwestern.edu

www.usatoday.com.

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