As if we were a worm, as if, paraphrasing Paulo Coelho , we all shine with our own light, the body of a human being emits visible light and the intensity of the light rises and falls throughout the day (this visible light differs from the infrared radiation, an invisible form of light, that comes from body heat).
But why don’t we see it? Because it is 1,000 times less intense than the levels to which our naked eyes are sensitive .
All creatures do
In fact, we are not dealing with a human superpower : practically all living creatures emit very weak light, which is believed to be a by-product of biochemical reactions that involve free radicals.
To learn more about this faint visible light, Japanese researchers used remarkably sensitive cameras capable of detecting single photons . Five healthy male volunteers in their 20s were placed bare-chested in front of cameras in complete darkness in light-proof rooms for 20 minutes every three hours from 10 am to 10 pm for three days.
The researchers found that body brightness rose and fell during the day, with its lowest point at 10 a.m. and its peak at 4 p.m. These findings suggest that there is a light emission related to body clocks , probably due to how our metabolic rates fluctuate throughout the day.
Also, the faces were brighter than the rest of the body . This may be because the faces are more tanned than the rest of the body, as they are exposed to more sunlight. The pigment behind skin color, melanin, has fluorescent components that could amplify the body’s tiny light output.
Since this dim light is linked to the body’s metabolism, this finding suggests that cameras that can detect weak emissions could help detect medical conditions.
One more proof that most of what surrounds us is invisible to us, and that we must use science, and also the measuring instruments created thanks to technology, to establish models that allow us to get a little closer to the pale reflection of reality :