Actually, everything with a temperature above 0 Kelvin emits light. But our glow is not just from body heat-the amount of light and the amount of heat we give off do not match, meaning we are slightly bioluminescent. Scientists found that we give off light in a 24-hour cycle, and that the brightest light comes from our cheeks, forehead, and neck.
What is Bioluminescence?
Bioluminescence is the production and emission of light by a living organism. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria and terrestrial invertebrates such as fireflies.
How does bioluminescence happen?
The chemical reaction that results in bioluminescence requires two unique chemicals: luciferin and either luciferase or photoprotein. Luciferin is the compound that actually produces light. In a chemical reaction, luciferin is called the substrate.
What are some bioluminescent animals?
At dusk, cells produce the chemicals responsible for its light. Bioluminescence is found in many marine organisms: bacteria, algae, jellyfish, worms, crustaceans, seastars, fish, and sharks to name just a few. In some cases, animals take in bacteria or other bioluminescent creatures to gain the ability to light up.
Source: curiosity and google