Morrisey, the frontman for the iconic 80s alternative rock band The Smiths, famously proclaimed that “There is a light that never goes out.” While the light Moz was referring to is up for debate, when it comes to living beings, a group of scientists is saying that there is indeed a light that goes out, and it does so at the time of death.
A team of scientists led by Vahid Salari, a professor in the department of physics and astronomy at the University of Calgary, found that living beings emit a light so faint it’s invisible to the naked eye. However, when they die, so too does that light.
Writing in the Journal of Physical Chemistry Letters, Salari and team note a biological phenomenon known as ultraweak photon emission, or UPE. The phenomenon was observed in mice, with live mice emitting a “significantly higher UPE intensity” compared to their recently euthanized counterparts, as Sanjukta Mondal at Phys.org explains.
To capture the light emissions, the University of Calgary researchers used high-tech imaging equipment, as well as “ultradark” enclosures that removed any “environmental light interference.”
When the images were analyzed, the researchers noted that while the living and dead mice had the same body temperatures –– 37 degrees Celsius –– the live mice showed “robust” UPE emissions, compared to the UPE emissions of the dead mice, which were “nearly extinguished,” Mondal writes.
UPE is the result of metabolism in the cells, which produces a byproduct known as reactive oxygen species, or ROS. According to Mondal, studies suggest that when an organism is stressed, biochemical pathways are activated, which in turn generate ROS. Too much ROS can then lead to “oxidative stress,” which subsequently excites electrons and causes UPE.
However, Mondal notes that “Despite being so widely observed, not much is known about the impact of mortality and stress factors on UPE.”
The phenomenon has been observed in myriad life forms, including single-celled organisms and bacteria, plants, animals and humans.
Mondal says that based on the researchers’ findings, UPE imaging could eventually be used as a non-invasive tool for not only conducting research but also diagnosing patients in a clinical setting.
