Ultraviolet or UV light has a shorter wavelength than visible light, so we cannot see it.
Ultraviolet radiation possess higher energy than visible light, and are responsible for causing our sunburns. UV light can cause some type of skin cancers also. UV light can be reflected strongly from the surface of water and from white surfaces such as snow and can cause snow blindness. It is always better to wear protective goggles or sunglasses that filter out the UV light to prevent serious eye damage.
Though some UV rays from the sun penetrate earth’s atmosphere most of them are blocked from entering by various gases like ozone. However, increasing damage done to the ozone layer in the earth’s upper atmosphere means that more and more UV light is now reaching the surface of the Earth. This is dangerous to us.