Electromagnetic solar radiation
The Sun continuously emits two kinds of radiation: electromagnetic and corpuscular.
Energy from the Sun at the speed of light in the form of a wave
Electromagnetic solar radiation is a phenomenon by which energy escapes from the Sun at the speed of light in the form of a wave. There are several types of radiation that can be expressed in terms of energy, wavelength or frequency (number of waves per second). The best known type of the spectrum is visible sunlight.
In a rainbow, the solar rays are arranged according to their wavelength (see above illustration). From purple to red, the wave gets longer. The infrared, with a wavelength larger than the one of red, is not visible, but we feel its warmth. The ultraviolet (UV) has a wavelength smaller than the one of purple. This part of the solar radiation, which is not visible either, can be harmful for humans.