Humans give off visible light that vanishes when we die, new study shows

It turns out the idea that humans glow might not just be poetic. A new study from the University of Calgary and the National Research Council of Canada has captured physical evidence showing that living organisms, including mice and plants, emit a faint visible light that vanishes upon death.

This barely-there glow, known as ultraweak photon emission (UPE), is produced by chemical reactions inside cells. While these biophotons are far too dim for our eyes to see, they’re very real, and scientists have now observed the glow flicker out in real time.

Biophotons aren’t a new concept, though they’ve often been treated as fringe science. They differ from more familiar forms of bioluminescence (like glowing jellyfish or even barrelfish) and are emitted as cells deal with stress or damage. However, this is one of the first times science has posited that humans themselves glow.

The source of the glow is believed to be byproducts of metabolism that sometimes create high-energy reactions capable of releasing light.

A new study focused on whether this phenomenon could be seen across an entire living subject, not just in isolated cells or tissues. To test this, researchers placed live mice into completely dark imaging chambers and used high-sensitivity cameras to record their biophoton emissions.

After about an hour, the mice were euthanized, but kept warm to rule out temperature effects. Imaging continued for another hour. According to a study published with their findings, the researchers observed a dramatic decrease in photon emissions after death.

The same was observed in plant leaves from thale cress and umbrella trees. Injured parts glowed more brightly than healthy ones, which the researchers say is clear evidence that living stress responses drive the emission.