Ultraviolet

Ultraviolet radiation, or UV radiation is the shortest wavelength of electromagnetic radiation radiated from the sun, constituting about 10% of the total light output of the sun. The wavelength of the radiation is between 10nm to 400nm. UV radiation affects pigments in human skin, making it brown. Exposure to UV radiation is a major risk factor for most skin cancers, due to UV rays damaging the DNA in skin cells. Exposure to UVB however, will stimulate the production of Vitamin D. UVB radiation also inactivates bacteria. The UV’s ability to inactivate bacteria and viruses is also used to sterilise surfaces of things such as medical equipment.

Very hot objects emit some amount of UV radiation: the hotter the object, the more UV is emitted. This can be utilized in the field of astronomy, to observe solar systems and other space stuff.