What are Ultraviolet (UV) Rays? Where Do They Come From?

It is a well-known fact that sunlight is made up of seven colors. These seven colors are just the ones humans can see; however, sunlight contains other colors beyond these. Color refers to the wavelength of the ray, and every color has its own distinct wavelength. The first color we can see at one end of the spectrum is violet. The color before it, ultraviolet, is invisible to us. However, some insects like bees, as well as certain animals and birds, can see this color. These ultraviolet rays are intense enough to burn the skin and damage the eyes.
Fortunately, not all ultraviolet rays coming from the solar system reach the Earth. When they enter Earth's atmosphere, they react with oxygen to create ozone gas, forming a protective layer. The ozone layer shields us from ultraviolet rays.
That said, our bodies do need a small amount of ultraviolet light, as it helps produce Vitamin D in the skin. Because these rays are intense, they also destroy disease-causing bacteria. Scientists have developed lamps that generate ultraviolet rays, which are useful in treating many medical conditions.