Ultraviolet light is a type of light that exists just beyond what human eyes can see. The name comes from its position in the spectrum of light: “ultra” means beyond, and violet is the last color we can see before light becomes invisible to us.

Sunlight contains ultraviolet light, often called UV light or UV rays. This invisible light is what causes sunburns when you spend too long outside without protection. It's also why doctors and parents remind you to wear sunscreen: too much UV exposure can damage your skin.

But ultraviolet light isn't all bad. It helps your body produce vitamin D, which keeps your bones strong. Scientists use special UV lights to study things invisible to the naked eye: forensic investigators use UV light to find evidence at crime scenes, and museums use it to authenticate old paintings. Some animals, like bees and certain birds, can actually see ultraviolet light, which helps them find flowers and navigate.

You might see blacklights at parties or mini-golf courses. These produce ultraviolet light that makes white clothing and certain colors glow brilliantly. What looks like magic is actually UV light causing special chemicals in fabrics to fluoresce, meaning they emit visible light.