7 days ago
Humans Give Off a Light That Is Extinguished in Death, Study Reveals
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While auras may come from the realm of pseudoscience, all living beings do emit a faint light, invisible to the human eye—one that is extinguished upon death.
This is the conclusion of a team of researchers from the University of Calgary, Canada, who used a special camera to study such "ultraweak photon emission" (UPE) in mice.
UPE is closely linked to vitality," explained physicist Vahid Salari and colleagues in their paper, published in The Journal of Physical Chemistry Letters.
"The study of UPE has fundamental importance for basic research, as it can be used for non-invasive insights into the biochemical and metabolic processes of living organisms."
Stock image of a man glowing.
Stock image of a man glowing.
bestdesigns/iStock / Getty Images Plus
UPE has been detected coming from a multitude of life forms—all the way up from single-celled organisms to plants, animals and even us humans.
Unlike bioluminescence (as seen in creatures like fireflies and glowworms), which releases high-intensity visible light, UPE results in extremely low-intensity light our eyes cannot see. It is also separate to the blackbody radiation emitted as a result of temperature.
According to the researchers, at the heart of UPE is the production of so-called reactive oxygen species, or ROS for short.
(These, as their name might suggest, are highly reactive oxygen-containing molecules that result as a byproduct of the chemical reactions that sustain all living things.)
ROS play a role as signaling molecules in the cellular response to stress. If too many of these molecules are produced, however, they can actually cause oxidative stress.
When this overwhelms a cell's antioxidant defenses, cells and tissues can be damaged and electron excitation and transfer processes can be induced, leading to photon emission.
In their study, the researchers created ultradark enclosures to block out environmental light and allow UPE from living organisms to be detected via specialist cameras.
A so-called Electron-Multiplying Charge-Coupled Device (EMCCD) camera was used to capture UPE from plants, while a "regular" Charge-Coupled Device (CCD) to observe the changes in ultraweak photon emission between live and dead mice.
While live mice gave off robust emissions, the team found just-euthanized mice—despite having the same body temperature of 98.6 degrees Fahrenheit—gave off robust UPE.
UPE from live (top) and dead (bottom) mice.
UPE from live (top) and dead (bottom) mice.
Salari et al. / The Journal of Physical Chemistry Letters
Experimenting on plants, meanwhile, the researchers found that UPE emissions increased with both temperature and injuries—although the latter could be mitigated with chemical treatment.
The findings, the team concluded, highlight how "UPE imaging provides the possibility of non-invasive label-free imaging of vitality in animals and the responses of plants to stress."
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Reference
Salari, V., Seshan, V., Frankle, L., England, D., Simon, C., & 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.
