The solar spectrum is the entire set of electromagnetic radiation emitted by the Sun. This spectrum includes all wavelengths of light, from infrared to visible to ultraviolet, covering a very wide range.
Visible light is only a small part of the solar spectrum and includes colors ranging from red to violet, with wavelengths ranging from about 400 to 700 nanometers. Visible light from the Sun appears white, but is actually made up of many different colors, which can be separated by a prism or by raindrops, creating a rainbow.
Infrared represents a significant portion of the solar spectrum and has longer wavelengths than visible light. This radiation is responsible for the heat we feel when we are exposed to the sun. Although invisible to our eyes, infrared is essential for warming the Earth’s atmosphere and maintaining a livable climate.
Ultraviolet (UV) has shorter wavelengths than visible light and, although invisible, has important effects. UV radiation is divided into three categories: UVA, UVB and UVC. UVA penetrates deeper into the skin and is associated with premature aging, while UVB is the main cause of sunburn and can damage the DNA of skin cells. Most UVC is blocked by the Earth’s atmosphere.
The solar spectrum is essential for life on Earth, it regulates the climate and influences the water cycle. Our health also depends on proper exposure to sunlight: it stimulates the production of vitamin D, essential for bones and the immune system.
