Radiant Energy

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Visible light is electromagnetic energy emitted at wavelengths our eyes can see. Electromagnetic energy emitted at wavelengths we cannot see may take the form of infrared radiation, ultraviolet radiation, X-rays, gamma rays, and radio waves. Gamma rays have wavelengths much shorter than visible light. Radio waves are the opposite. Their frequencies are far longer than the longest waves our eyes can see.

Figure 5
Electromagnetic spectrum
The electromagnetic spectrum includes radio, infrared, visible light, ultraviolet, x-rays, and gamma rays.

Solar radiation, a term used to describe all electromagnetic radiation emitted by the sun, including visible light, passes through the atmosphere, is absorbed, and re-radiated back out to space as infrared (heat) waves.