For decades, scientists have suspected that living organisms emit faint glimmers of light, invisible to unaided eyes yet potentially meaningful. Recent experiments using ultra-sensitive photon detectors have finally captured that elusive glow across entire animals and plants, revealing subtle visual signatures of metabolism, stress, and death.
Ultraweak Photon Emission: Oxidative Reactions as Light Sources in Living Systems
Whole-Organism Imaging Confirms Reactive Oxygen Pathways Emit Measurable Photons
From Fringe Theory to Measured Reality
Before the data and the headlines, the idea that living things emit a glow lived in the margins of science, whispered about by early biophysicists, dismissed by skeptics, and patiently waiting for technology to catch up.
The phenomenon is known as ultraweak photon emission or UPE. It is also sometimes referred to as biophoton release. The photon emission arises during ordinary oxidative reactions within cells or particularly those involving reactive oxygen species that generate electronically-excited molecules capable of shedding energy as single photons.
Early pioneers documented related effects during the 20th century. For example, between 1920 and 1930, Russian biologist Alexander Gurwitsch reported in 1920s faint UV light supposedly emitted by dividing cells. German biophysicist Fritz-Albert Popp coined the term biophotons while measuring UPE in humans, plants, and DNA solutions.
The phenomenon faced limited acceptance since detectors produced inconsistent results. Modern electron multiplying charge-coupled devices now provide sufficient sensitivity to track individual photons. This allowed a team of researchers from the University of Calgary and the Canadian National Research Council to revisit unanswered questions.
Nevertheless, to measure UPE, the team placed live mice and plant specimens inside light-sealed imaging chambers equipped with advanced detectors and vibration-dampening supports. Each was recorded nonstop during quiet resting periods, followed by controlled stress, injury, or termination for comparison across different physiological conditions.
The Quietest Light Show on Earth
Once the cameras were rolling and every light was sealed away, biology finally revealed its secret. What followed was part science, part spectacle — a quiet display of photons rising and falling with life, stress, and silence.
The resulting images confirmed that UPE reflects biological activity rather than incidental background noise. Several consistent patterns emerged across animal and plant subjects. These demonstrate both decreases during metabolic cessation and increases during heightened physiological demand. The following are the key findings:
• Cessation Response: Mouse subjects exhibited immediate reduction of emission following controlled termination, even after reheating procedures, confirming dependence upon active metabolism rather than mere thermal radiation.
• Injury Response: Cut leaves displayed significantly brighter regions surrounding damaged areas for extended periods, indicating localized oxidative bursts associated with cellular repair processes or defense signaling pathways.
• Chemical Response: Application of benzocaine produced the most pronounced light increase among the tested compounds. This suggests that disruption of normal ion transport stimulates elevated reactive oxygen activity across plant tissues.
Where This Discovery Could Lead Us
The implications stretch far beyond curiosity. What began as an invisible flicker could soon become a diagnostic tool, an agricultural monitor, or even a new language for understanding cellular behavior — without touching a single cell.
Remember that ultraweak photon emission occurs because living cells produce a small amount of stress while using oxygen to burn fuel for energy. That stress creates unstable molecules that briefly store energy in an excited form. Nevertheless, when these excited molecules settle down, they release the extra energy as a single photon or a weak flash of light.
Moreover, because it is classified as an ultraweak photon emission, the emitted light belongs to the lowest end of the visible light and near ultraviolet section of the electromagnetic spectrum. It is a form of electromagnetic radiation, similar to radio waves and microwaves or infrared or ultraviolet radiation, but released as individual photons in extremely small quantities.
The light emitted by living organisms belongs to the lowest end of the visible and near ultraviolet spectrum, classified as ultraweak photon emission. It is a genuine form of electromagnetic radiation, just like sunlight or radio waves, but released as individual photons in extremely small quantities.
The aforesaid outcomes suggest that noninvasive optical monitoring could eventually serve as a valuable diagnostic platform across numerous medical and agricultural settings. Continuous tracking of ultraweak emission may reveal early signs of tissue dysfunction or dehydration long before visible symptoms become apparent to human observers.
Further development of handheld photon-sensing devices could allow farmers to survey entire fields for stress hotspots using automated drones. Physicians could likewise screen skin surfaces for abnormal metabolic patterns potentially indicative of emerging pathology, providing safer alternatives to invasive biopsy procedures or ionizing scans.
Careful interpretation will remain crucial because ultraweak emission arises naturally from diverse biochemical pathways and fluctuates with temperature changes. Variations in signals must be correlated with additional biomarkers and environmental parameters before definitive conclusions regarding health or stress conditions can be drawn responsibly.
FURTHER READING AND REFERENCE
- Salari, V., Seshan, V., Frankle, L., England, D., Simon, C., and Oblak, D. 2025. “Imaging Ultraweak Photon Emission from Living and Dead Mice and from Plants under Stress.” The Journal of Physical Chemistry Letters. 16(17): 4354-4362. DOI: 1021/acs.jpclett.4c03546