A new study has revealed that all living things, including humans, mice, and plants, give off a faint natural glow during life, a light that disappears the moment life ends. The research, carried out by scientists at the University of Calgary and the National Research Council of Canada, was published in The Journal of Physical Chemistry Letters. Experts say this glow, known as ultraweak photon emission, could open the door to new ways of monitoring health, stress, and even crop conditions.
This has fascinated scientists and ordinary people alike, because it shows that life itself carries a hidden signature of light. For many years, researchers suspected that living cells might emit tiny bursts of photons, but now, for the first time, scientists have been able to capture this glow across entire organisms. “It’s almost poetic to think that life shines in darkness, even if the glow is too faint for our eyes to see,” said lead physicist Vahid Salari.
The phenomenon is called biophoton emission. It is produced as a byproduct of metabolism inside cells, especially when they are under stress. These particles of light are incredibly weak, spread across wavelengths between 200 and 1,000 nanometers, and cannot be seen without very advanced cameras. To make the glow visible, the research team used electron-multiplying charge-coupled device cameras, devices so sensitive that they can pick up a single photon in a completely dark room.
The experiment was simple. Four mice were placed in a pitch-dark box and observed for one hour while alive. After being euthanized, the same animals were placed back in the box, kept warm to remove the effect of temperature, and observed again for another hour.
The results were clear, the photon emissions dropped sharply after death. “We saw a distinct change,” Salari explained. “The living bodies were glowing faintly, and the moment life ended, the light faded almost completely.”
The team also carried out similar tests on two plant species: thale cress and the dwarf umbrella tree. The leaves were stressed by either cutting or applying chemicals, and the cameras recorded the glow for 16 hours. The injured or stressed leaves emitted much more light compared to the healthy ones.
“Our results show that the injured parts in all leaves were significantly brighter than the uninjured parts,” the researchers reported. This finding shows that the natural glow of plants may act as a signal of stress or damage, one that could be detected long before the plant visibly withers.
Scientists believe the source of this glow is reactive oxygen species, or ROS. These unstable molecules are produced when cells face pressure from heat, toxins, or pathogens. While ROS can damage cells, they also trigger chemical reactions that cause electrons to release photons as they stabilise.
In other words, the faint glow of life is the result of cells fighting to stay alive. “Reactive oxygen species are like sparks in the machinery of life,” one researcher explained. “And those sparks release the tiny flashes of light that we can now measure.”
The potential applications of this research are huge. In medicine, doctors may one day use photon emission to monitor tissue health without surgery or invasive samples. Instead of cutting open a patient, they might simply scan for the glow to check which organs are under stress. In agriculture, farmers could use the same technology to measure crop health, spotting early signs of disease or poor soil conditions by looking at the brightness of the leaves.
The work is still experimental. The equipment required to measure ultraweak photon emission is expensive and complicated. Every day use in hospitals or farms is still a long way off. But scientists believe that as technology advances, these faint lights could become a powerful diagnostic tool.
For centuries, people have spoken of the body having an aura or a life force that vanishes with death. While many of those ideas are rooted in spiritual or mystical beliefs, the new research shows that there is, in fact, a scientific basis for a glow that belongs to the living and disappears when life ends.
Salari was quick to point out, however, that this is not about the supernatural. “We are talking about chemistry and biology, not mysticism,” he said. “But it is true that life, quite literally, radiates.”
The study reminds us that even the smallest details of biology can reveal beauty. Life does not just exist in silence—it shines, however softly, in the dark. And when that light is gone, it marks the final boundary between life and death.
This research, published in 2025, showed a new perspective on how we may one day understand health, disease, and the very nature of being alive. One scientist said,“Life is radiant. We just needed the right tools to finally see it.”
