The sun emits a broad spectrum of radiation. We call the visible part of it ”light”. Other parts are invisible, but have important functions. Infrared radiation, for instance, supplies us with heat. Ultraviolet radiation, UV in short, provides the solar energy which is vital for so many biological processes. However, too much UV radiation can be harmful to many forms of life.
UV radiation from the sun can be split up into several ranges.
Like visible light, UV-A and UV-B penetrate the protective atmosphere surrounding the earth and reach the ground. However, UV-C, which has a particularly high energy content and would therefore be extremely harmful, never reaches the earth’s surface.
UV-B radiation has a higher energy content than UV-A and can cause sunburn. Logically enough, solar radiation which burns the skin can also injure various layers of tissue in the eye.
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