Biophotons (or ultra weak photon emission) has been known about for decades. Various reactive oxidative molecules release light when coming down from an excited state. Some enzymatic activity is also known to produce light.
The big question has been just how much useful information can be derived from that light? It is difficult to tease out signal from noise and the human body is far from transparent at those frequencies so it's not like you could use it for imaging.
Since breathing stops and various oxidation reactions thus also slow or stop it makes sense the emitted light would decrease.
taejavu · 1h ago
Forgive my ignorance - at what point does electromagnetic radiation not count as light? Because it seems obvious to me that since our bodies are warm, and heat is a form of EMR, then of course we radiate "light". But also, things that wouldn't be described as warm still do this - all matter in the universe emits EMR, does it not?
Would someone be so kind as to clear up my long-held misconceptions?
volemo · 9m ago
> at what point does electromagnetic radiation not count as light?
At the point when its wavelength is outside of visible range, roughly 380 to 750 nm. (Some experts will call (parts of) IR and UV radiation “light”, but that’s neither here nor there.)
> Because it seems obvious to me that since our bodies are warm, and heat is a form of EMR, then of course we radiate "light".
Of course, everything radiates, and everything radiates light if you heat it up enough (> 500°C, > 1000°F).
> But also, things that wouldn't be described as warm still do this - all matter in the universe emits EMR, does it not?
Yep, only things at absolute zero temperature truly do not radiate, and it’s impossible to get there.
However, afaiu, the study describes chemiluminescence, i.e. specifically radiation above thermal.
nine_k · 59m ago
Emitting heat is obvious, well-known, and thus uninteresting. Humans do not see in the IR range, so the interesting thing is emitting light in the visible spectrum range. It also has various mystical / magical / religious connotations in the traditional culture for millennia.
userbinator · 3h ago
UPE, also known as biophoton emission, is a spontaneous release of extremely low-intensity light that is invisible to the human eye and falls within the spectral range of 200–1,000 nm
Part of that is in the infrared spectrum, and the other end in UV (including A, B, and C). Isn't this just https://en.wikipedia.org/wiki/Black-body_radiation that everything with a non-zero absolute temperature emits? Dead beings would obviously cool down and reduce the amount of radiation they emit.
throw10920 · 2h ago
> Isn't this just...black-body radiation?
I think that they explicitly controlled for that. From the article:
> The results revealed that despite both groups having the same body temperature of 37°C, the live mice showed robust emissions, whereas the UPE from the euthanized mice was nearly extinguished.
It's possible that they controlled improperly, but that's another question - from my reading of the above, they artificially heated the corpses (or measured immediately after death) to control for blackbody radiation.
addaon · 3h ago
> invisible to the human eye
Also unclear how the light would be invisible to the human eye, given that the human eye has single-photon sensitivity smack in the middle of that range.
throw10920 · 2h ago
I noticed that too and I agree that sounds wrong - I suspect the authors of the popsci phys article were being hasty and wrote poorly, using "invisible" to refer to the intensity, separate from the frequency (even though it's misleadingly mentioned immediately after).
Or maybe they're just wrong and didn't realize that 500 nm is visible light - that's possible too.
Waterluvian · 3h ago
> UPE varied depending on exposure to stress factors like temperature changes, injury and chemical treatments
I haven’t read the study but I studied remote sensing in undergrad and one thing we worked on was how to detect the stress of an agricultural crop from multispectral satellite data. You can quite clearly detect how plants are handling temperature, pest damage, drought conditions, largely based on their near- and middle-infrared responses. On the surface this sounds a lot like that, which I think is neat.
efnx · 3h ago
Anyone who has seen the movie Predator already knows this ;)
franky47 · 1h ago
Isn’t that a thermal image showing body warmth on infrared?
The OP title made me think of the aura seen by Xenomorphs in the original Alien vs Predator video games.
3oil3 · 3h ago
So we do have an "aura"?? Magical!
amarant · 2h ago
Well, mice do, if this study is to be believed anyway.
lostmsu · 2h ago
In mice.
markhahn · 47m ago
Woo-oriented people find this fascinating.
But talk to an electrical/computer engineer about it though. To be a signal, such light needs to be both received and aimed...
moralestapia · 2h ago
What a beautiful finding.
Of note, 200-1,000 nm overlaps with the wavelengths we perceive.
Could it be that under some particularly dark environments, some particularly sensitive humans (or animals) can get a glimpse of it? I believe it's quite plausible.
michaelmrose · 25m ago
No because the amount of illumination is dwarfed by the amount that must bounce on off from more normal sources for us to be aware of things.
nprateem · 1h ago
There's s knack to seeing auras. You need to soften your focus and kind of look more with peripheral vision than in the centre.
It's pretty easy to see the layer closest to the body. It's kind of like a bright outline about 1cm thick.
The layer with colours is further out and I've only ever seen it once. It was rad though, 10cm apple green flames appearing to shoot off my body as I moved my eyes around.
Certain lighting conditions make it easier, eg slightly dark environment with a backlit subject.
Anyway cue the downvotes from the overly analytical people here. As with all things meditation, the more you try the less you'll experience.
jwrallie · 33m ago
I can see colors on the periphery of my vision when black contrast with white too, and it is just... chromatic aberration from my glasses. Does not happen in a detectable level with my contacts.
michaelmrose · 23m ago
The downvotes are because this is unreal. You are describing hallucinations. Lots of people have them.
The big question has been just how much useful information can be derived from that light? It is difficult to tease out signal from noise and the human body is far from transparent at those frequencies so it's not like you could use it for imaging.
Since breathing stops and various oxidation reactions thus also slow or stop it makes sense the emitted light would decrease.
Would someone be so kind as to clear up my long-held misconceptions?
At the point when its wavelength is outside of visible range, roughly 380 to 750 nm. (Some experts will call (parts of) IR and UV radiation “light”, but that’s neither here nor there.)
> Because it seems obvious to me that since our bodies are warm, and heat is a form of EMR, then of course we radiate "light".
Of course, everything radiates, and everything radiates light if you heat it up enough (> 500°C, > 1000°F).
> But also, things that wouldn't be described as warm still do this - all matter in the universe emits EMR, does it not?
Yep, only things at absolute zero temperature truly do not radiate, and it’s impossible to get there.
However, afaiu, the study describes chemiluminescence, i.e. specifically radiation above thermal.
Part of that is in the infrared spectrum, and the other end in UV (including A, B, and C). Isn't this just https://en.wikipedia.org/wiki/Black-body_radiation that everything with a non-zero absolute temperature emits? Dead beings would obviously cool down and reduce the amount of radiation they emit.
I think that they explicitly controlled for that. From the article:
> The results revealed that despite both groups having the same body temperature of 37°C, the live mice showed robust emissions, whereas the UPE from the euthanized mice was nearly extinguished.
It's possible that they controlled improperly, but that's another question - from my reading of the above, they artificially heated the corpses (or measured immediately after death) to control for blackbody radiation.
Also unclear how the light would be invisible to the human eye, given that the human eye has single-photon sensitivity smack in the middle of that range.
Or maybe they're just wrong and didn't realize that 500 nm is visible light - that's possible too.
I haven’t read the study but I studied remote sensing in undergrad and one thing we worked on was how to detect the stress of an agricultural crop from multispectral satellite data. You can quite clearly detect how plants are handling temperature, pest damage, drought conditions, largely based on their near- and middle-infrared responses. On the surface this sounds a lot like that, which I think is neat.
The OP title made me think of the aura seen by Xenomorphs in the original Alien vs Predator video games.
But talk to an electrical/computer engineer about it though. To be a signal, such light needs to be both received and aimed...
Of note, 200-1,000 nm overlaps with the wavelengths we perceive.
Could it be that under some particularly dark environments, some particularly sensitive humans (or animals) can get a glimpse of it? I believe it's quite plausible.
It's pretty easy to see the layer closest to the body. It's kind of like a bright outline about 1cm thick.
The layer with colours is further out and I've only ever seen it once. It was rad though, 10cm apple green flames appearing to shoot off my body as I moved my eyes around.
Certain lighting conditions make it easier, eg slightly dark environment with a backlit subject.
Anyway cue the downvotes from the overly analytical people here. As with all things meditation, the more you try the less you'll experience.
It is also brighter the further you die from home.