Fireflies and jellyfish glow. So, in a tiny way, do you. In 2009, scientists in Japan captured photographs of visible light coming from human skin. Nobody in the room could see it, but a special camera could.
The experiment
Researchers at the Tohoku Institute of Technology placed five healthy young men, one at a time, in a completely dark, light-sealed room. They sat bare-chested in front of an extremely sensitive camera, cooled to very low temperatures so it could detect single particles of light.
Each session lasted 20 minutes and was repeated every three hours from 10 am to 10 pm, over three days. The study was published in the journal PLoS ONE.
What they found
The human body really does give off a faint visible light. The glow was about 1,000 times weaker than what the naked eye can detect. It is not body heat: heat comes out as infrared light, which is a different thing.
The face glowed more than the rest of the body. And the glow followed a daily rhythm: it was weakest around 10 am and strongest around 4 pm, then fell again toward evening.
Where does the light come from?
Scientists think it is a side effect of metabolism. As cells use energy, they produce reactive molecules. When these react with fats and proteins, a tiny amount of energy can be released as light.
Keep it in proportion
The colourful pictures from the study use false colours to show brightness. They are not what a person would see, and the study was very small. This is not an “aura”. It is ordinary chemistry, measured with an extraordinary camera.
In short
- The human body gives off real visible light.
- It is about 1,000 times too faint for human eyes.
- In one study, the glow peaked around 4 pm and was strongest on the face.
Sources
- Kobayashi et al. (2009), PLoS ONE: Imaging of ultraweak spontaneous photon emission from human body
- Live Science: Humans glow in visible light
This article is for curiosity and learning only and is not medical advice.