UV light is radiation energy in the form of invisible light waves. UV light is emitted by both the sun and tanning lamps. The sun discharges three types of ultraviolet radiation: ultraviolet A (UV-A), ultraviolet B (UVB), and ultraviolet C (UVC). Only UVA and UVB reach the earth. UVC does not penetrate the earth’s upper atmosphere. Although research has long implicated UVB as the most likely form of UV to damage the skin and cause skin cancer, recent studies suggest that UVA is also dangerous. Tanning lamps also produce UVA and/or UVB. These artificial rays affect the skin in the same way as UVA and UVB from the sun.