Source: www.livescience.com
July 22, 2009: Scientists have learned that the human body literally glows, emitting a visible light in extremely small quantities at levels that rise and fall with the day.
Past research has shown that virtually all living creatures, including humans, emit visible light. Thought to be a byproduct of biochemical reactions, this light is 1,000 times less intense than the levels to which our naked eyes are sensitive. It is different from the infrared radiation (an invisible form of light) that comes from body heat.
Scientists in Japan studied this faint visible light with extraordinarily sensitive cameras capable of detecting single photons. They found the body glow rose and fell over the day, with its lowest point at 10 a.m. and its peak at 4 p.m., dropping gradually after that. Faces glowed more than the rest of the body.
Some scientists postulate that since the glow appears to be produced by metabolic processes, super-sensitive cameras could help spot medical conditions. “If you can see the glimmer from the body’s surface, you could see the whole body condition,” said researcher Masaki Kobayashi, a biomedical photonics specialist at the Tohoku Institute of Technology in Sendai, Japan.