It was revealed by ultra-sensitive cameras that our bodies emit tiny amounts of light that are too weak for the human eye to detect. Amazing pictures of "glittering" human bodies were released by Japanese scientists who have captured the first ever images of human "bioluminescence". Although it has been known for many years that all living creatures produce a small amount of light as a result of chemical reactions within their cells, this is the first time light produced by humans has been captured on camera. Strangely, the areas that produced the brightest light did not correspond with the brightest areas on thermal images of the volunteers' bodies. (Link)

Strangely, the areas that produced the brightest light did not correspond with the brightest areas on thermal images of the volunteers' bodies.

The light is a thousand times weaker than the human eye can perceive. At such a low level, it is unlikely to serve any evolutionary purpose in humans – though when emitted more strongly by animals such as fireflies, glow-worms and deep-sea fish, it can be used to attract mates and for illumination.

Bioluminescence is a side-effect of metabolic reactions within all creatures, the result of highly reactive free radicals produced through cell respiration interacting with free-floating lipids and proteins. The "excited" molecules that result can react with chemicals called fluorophores to emit photons.