The human body has been found to emit light, but in extremely small amounts — about 1,000 times lower than the sensitivity of the human eye. The process of the body releasing energy as light is known as bioluminescence. This process was once thought to occur only in certain animals, but researchers discovered with the use of cameras that were hypersensitive to light that human beings also emit trace amounts of light. The light intensity emitted from humans tends to operate in 24-hour cycles. In the late afternoon, the light tends to be brightest, and the levels are their dimmest at night.
More about bioluminescence:
- It is estimated that at least 80% of ocean creatures emit light to help them see in the dark, deep water.
- Fireflies are thought to use bioluminescence as a tactic to advertise to bats that the insects might be toxic and should not be eaten.
- Five species of seaworms create bioluminescent bombs, which are capsules filled with liquid that glows when it bursts. They launch these capsules to distract predators and escape.
