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Issue Date: March 9, 2008
Auroras light up the sky like neon
By Julian Smith
Auroras commonly appear as swirling curtains of green.
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March is not just a season of emerging spring flowers. Look up at night and, depending on where you are, you might be lucky enough to spot a spectacular light display known as the aurora.
Alaska and northern states are the best places in the United States to see the heavens put on their show.
The phenomenon is called the aurora borealis, or northern lights, in the Northern Hemisphere and the aurora australis in the south, below the equator, where it is much less visible. The colorful displays are named for Aurora, the Roman goddess of dawn. Ancient people had many explanations for the source, including rings of fire that surrounded a flat Earth.
Modern scientists offer a more plausible cause. They believe that the colorful lights are created by streams of high-energy particles, called the solar wind, that are trapped in Earth's magnetic field and flow toward the poles. These particles collide with oxygen and nitrogen in Earth's atmosphere to light up the sky.
When solar activity is high, as it is this month, auroras expand from the polar regions toward the equator.
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