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People Emit Visible Light
An Anonymous Reader writes "The human body literally glows, emitting a visible light in extremely small quantities at levels that rise and fall with the day, scientists now reveal. Japanese researchers have shown that the body emits visible light, 1,000 times less intense than the levels to which our naked eyes are sensitive. In fact, virtually all living creatures emit very weak light, which is thought to be a byproduct of biochemical reactions involving free radicals."
This isn't any kind of new or unpredicted phenomenon. Everything that emits heat emits some light. The chances that the wavelength of a photon emitted by a human being (while giving off normal heat) will fall within the visible spectrum is very low, but given that we emit billions and billions of photons on a regular basis, it's sure to happen every now and then. Get sensitive enough cameras, and you'll see that glow from everything that isn't at absolute zero.
Not really a halo...
At least not to most people. Assuming that light sensitivity and light emission are independently normally distributed in the population, it's entirely possible that extremely sensitive individuals can see the light coming off the extremely bright individuals. Further, it is possible for genetically isolated populations to have gained extreme sensitivity or extreme brightness through the usual biological mechanisms, or if such traits were selected for through cultural or religious practices. Also, consider that relatively unstressed young Japanese men may not be fully activating whatever metabolism or physiology issues the light. There may be something to metabolism around "afterglow", women glowing when they're pregnant, unusual mental capacity, etc. which could easily generate 10 or 100 x the intensity observed in this study, and thus be observable by many people. (All sorts of biological processes span several orders of magnitude in concentration, intensity, energy, etc., and plenty of other bio-luminescent organisms show that the energy levels required to emit naked eye visible light are mostly not harmful to the organism.)
Whether we are consciously aware of the brightness of others, or if we do anything with that information are topics for future study.
There are 1.1... kinds of people.