World Book at NASA for Students
An aurora is a colorful glow that appears in the sky at night. Most auroras appear in the far northern and southern parts of the world. Auroras in the northern part of the world are called the northern lights. The colored lights appear as curved lines, clouds, and streaks. Some auroras move or get brighter or flicker suddenly. The most common color in an aurora is green, but sometimes auroras are red or purple.
Auroras form when the solar winds reach the Earth. The solar winds are a flow of particles, or tiny bits of matter, from the sun. The particles in solar winds contain electrical energy. When these particles strike other particles that surround the Earth, energy is released. Some of this energy appears in the form of auroras.
How to cite this article: To cite this article, World Book recommends the following format: "Aurora." The World Book Student Discovery Encyclopedia. Chicago: World Book, Inc., 2005.
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