Unformatted text preview: appears to be much higher than it actually is. A ring of light around the sun or moon is known as a halo. The halo is caused by sun or moonlight being refracted from ice crystals. The presence of ice crystals indicates the presence of cirriform clouds. Halos are often bright, white lights, but sometimes appear in colors. When white light is split into colors because of their respective wavelengths, the refraction is referred to as dispersion. Sundogs are caused by refraction through ice crystals. Sun pillars are caused by reflection off ice crystals. Rainbows occur when both rain and sunlight are present at the same time, as the light is reflected by the large water droplets. Secondary rainbows occur when the light enters the water droplets at such an angle that it reflects from the inside of the drop as well....
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- Spring '08