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http://www.passporttoknowledge.com/sun/main.html. What an Aurora!.
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http://www.passporttoknowledge.com/sun/main.html What an Aurora!
The sun gives off high-energy charged particles (also called ions) that travel out into space at speeds of 300 to 1200 kilometers per second. A cloud of such particles is called a plasma. The stream of plasma coming from the sun is known as the solar wind. As the solar wind interacts with the edge of the earth's magnetic field, some of the particles are trapped by it and they follow the lines of magnetic force down into the ionosphere, the section of the earth's atmosphere that extends from about 60 to 600 kilometers above the earth's surface. When the particles collide with the gases in the ionosphere they start to glow, producing the spectacle that we know as the auroras, northern and southern. The array of colors consists of red, green, blue and violet.
The Lights are constantly in motion because of the changinginteraction between the solar wind andthe earth's magnetic field.The oval normally extends over northern Finland and Scandinavia, the whole of Canada and the northern USA, Alaska and Siberia. The Aurora Australis is much less frequently observed because so few people live in Antarctica during the austral winter.
A cloud of magnetized gas from the Sun swept past Earth and rocked our planet's magnetic field. Northern sky watchers were delighted as red and green lights rippled across the sky. It was the aurora borealis -- breaking out for the third time this month.
