This is specifically not thermal (blackbody) radiation, which is negligible at the visible frequency range for mice at these temperatures. The researchers find a difference in visible wavelength emission between living and dead mice at the same temperature
This point is addressed on page 2 of the paper, accessible on bioarxiv:
The fact that they're seeing visible photon differences between live and dead tissue at the same temperature suggests it's tied to metabolic or biochemical activity, not just thermal noise
I should have added that this result wasn't unexpected or mysterious as it might sound, because it's known from physics that different chemical processes have characteristic photon emissions. Since it's known that different chemical processes occur in living and dead organisms, it was expected that there would be differing emissions in the two cases. As far as I know this research is the first actual detection of these differences
I believe there's an example of something similar happening when fertilization of an egg occurs. There's a zinc reaction which creates "flash" of visible light.
Animals (and plants? Bio 101 was a long time ago) use ATP for a lot of their metabolism and phosphates are pretty well known for emitting light as they react.
Sure but, in fairness, the HN title is a bit misleading. The paper says that the bodies are emitting light in the visible part of the EM spectrum not that the light is visible. And the intensity isn't really high enough to see the light without instruments.
True, there's an ambiguity in "visible light" between "EM radiation within the visible frequency range" and "EM radiation within the visible frequency range which is of sufficient intensity that we can detect it with our eyes"
But this is independent of the misconception that the radiation observed in this experiment is thermal. Thermal radiation in the visible range at this temperature is much lower in intensity than the biological radiation observed here, but both kinds of radiation are well below the intensity that we can see with our eyes.
Specifically from paper: The live/dead mice (and container) were all held at 37C, which google tells me is a normal mouse body temp. And, the observed light does not match the spectrum of black body radiation expected for the temps at which images were taken or subjects were held.
Also strange: The effect changed w/ injury or anesthetic treatment according to the abstract.
Specific electrochemical processes have their own characteristic photon emissions. Since there are some processes that occur distinctively in living organisms (e.g. to do with metabolism), it was previously thought that these would have characteristic photon emissions, but as far as I know these are the first observations of this kind of thing.
The effect changing with injury or anaesthetic I guess reflects the fact that there are different electrochemical processes occurring in these cases that have detectable differences in the photon emissions
I seem to recall the mechanism for anesthetics being something like temporarily depolarizing the mitochondrial walls to shut down ATP synthesis, so that might point towards where the effect is originating.
From the abstract the answer basically seems to be yes, and that's how they're pitching it.
They note increased emissions due to injury, which would be consistent with repair activities increasing the general intensity of chemistry happening to facilitate repair at wound sites.
Research is finding MicroTubules in the brain likely are the LINK (quantum entanglement) to where Consciousness "lives" (is located). Note that the Microtubules link STOPs while under Anesthesia.
Why does consciousness have to live somewhere? I currently prefer to think of it as an emergent phenomenon that arises (somehow, we have no clue) from the complex and distributed computations in the brain. Many different systems contribute, and saying that a single level of abstraction is where it lives seems meaningless. Kind of like saying that your video game “lives” in a transistor. It’s not wrong, but it’s not useful.
We don't seem to be able to find it inside the physical brain, and not for a lack of trying. Just throwing emergent behaviour out there changes nothing, just like it doesn't for AI.
What would "finding it" mean, whether inside the brain or out? It's quite easy to perturb consciousness by messing with the pieces of the brain, via pharmacology, injury, electrical stimulation, etc. I'm not sure why we need to assign responsibility to a single specific component like microtubules. That seems like saying the axle is responsible for a car moving. Sure, not wrong, but not right or explanatory either.
There are observed differences in brain function between conscious and unconscious patients. What's wrong with that as an initial characterization of "consciousness in the brain"? The investigation of these "neural correlates of consciousness" is quite a rich research field in its own right
Yeah he types weird and linked some generic YouTube search result that pops Joe Rogan up for some people, but there's some pretty interesting research along these lines that's becoming harder to dismiss as just Roger Penrose stepping way outta his field (I don't see people personally attacking Hameroff or Tuszynski for their roles in this research which always struck me as telling). I think it's more trying to zero in on how consciousness works from the perspective of trying to figure out how xenon administration in anesthesiology works to induce its effects.
Joe Rogan has interviewed plenty of people, different people that have very little in common, just because some of them have controversial views that make you nervous that doesn't mean all the information is useless.
We are constantly bombarded by links to information. It is reasonable to make snap judgments about the quality of the information based on who is providing it. If I’m looking for accurate, factual information on a topic that is clearly prone to magical thinking, a provider whose reputation is to listen to anyone, including people who very much engage in magical thinking, is actually a very bad source. Because they will not filter on anything beyond “is this neat to listen to.”
You are correct. However, Joe Rogan should not be the first stop for assessing the scientific plausibility of a new idea. If that is where someone is sending you, that can- and should- be a red flag.
Nothing weird or new about it: Suppose the foremost source for Dr. Example's claims happens to be the one time they interviewed on Coast To Coast AM [0]. That tells you something about the media-landscape they seek—or have been stuck inside.
I don't think it's the controversy of his guests so much as many of their unqualified ramblings that get treated as expertise. It's really obnoxious that it all gets put into political controversy when it's just often facially stupid BS.
Pretty much everything that is either capturing or releasing energy is giving off a spectrum of EM radiation. Usually it is mostly in the IR range, but you really just need sensitive enough equipment to get all sorts of EM noise.
Not "pretty much everything" but actually everything. The only way an object wouldn't emit radiation is if it was at absolute zero, which is something that exists literally no where in the universe.
That said, this light is not the result of just radiating heat and must have a different source.
That's UV, visible and near IR. We know that 100-600 nm (infrared EDIT: UV) light "can carry out photostimulation and photobiomodulation effects particularly benefiting neural stimulation, wound healing, and cancer treatment" [1]. I'm curious what could be producing UV and visible light.
Does light production tend to hang out around any particular organs or organelles? If stress causes it, I'd hypothesise it's metabolic or signalling related.
I would assume respiratory complexes I and III in mitochondria. Both used highly reduced states to create the gradient to pump protons, and electron leakage is inevitable.
This likely then leads to redox transitions in quinones, flavins, metal centres, leaving them in unstable excited states. When they relax, the excess energy has to go somewhere - usually thermal energy, but just occasionally, a photon.
This would also tally with anaesthetics and injury having an effect, as both effect mitochondrial function - and of course when you’re dead, so are your mitochondria.
The brain is electro-chemical, hold all sorts of minuscule charges… I guess once the process for keeping that all going comes to abrupt halt, electric potentials change which would take into account some electromagnetic field :shrugs:
I listened to the Radiolab podcast. I remained fairly unconvinced by the reporting on the show, but the part that really didn't make sense to me was, what is their definition of death? My (limited, non-medical) understand is that death has a bit of a spectrum associated with it. At what point does this light stop emitting? When you flatline exactly?
I came here with a similar thought. Given that we don't have a really precise definition of that transition from living to dead, I wonder if this could be it.
Some parts of the dead mice still emit in that spectrum. There won't be a clear and distinct "the lights went out" moment but a gradual fading, so you'll have to define some threshold to translate from radiation distribution and intensity do dead/alive. I don't think an image of photon emission will help pronounce someone dead.
Light is just a form of electromagnetic radiation. All processes produce electromagnetic radiation, only different in the amount. So as we improve our equipments, we naturally can see more things like that.
Kind of makes you wonder if this could eventually become a diagnostic tool, though I imagine the sensitivity requirements and ambient light issues are pretty brutal in real-world settings
You might enjoy The Light Eaters, it covers latest studies on plants for consciousness. I’m still very skeptical after reading it, I.e. how to differentiate between automaton like behavior derived from genetic programming and consciousness (argued for in the book) is still not clear to me.
I find it totally inline with expectations that, given sufficiently accurate measurement aparatus, one could detect a difference in light (and sound, and moves, and smell...) between living, stressed or dead things. After all, those are very distinguishable state of matter.
The visible range corresponds to the typical energy differences between different states of an outer electron in a molecule, which also correspond to the typical energy differences between the input and output molecules of a chemical reaction.
(The near infrared range corresponds to the typical energy differences between different vibrational states of the atoms in a molecule. Such energy differences are smaller than the energy differences encountered in most chemical reactions, which involve extracting or adding atoms from/to the molecule, which obviously needs more energy than the vibration of those atoms, when they remain bound in the molecule.)
Thus it is normal and expected that the output molecules of an exothermic chemical reaction may be in an excited state from which they can decay to their ground state by emitting light exactly in the visible range.
As long as it is living, in any organism a lot of exothermic chemical reactions happen. In many cases the energy produced by those reactions is used for something useful for the organism (i.e. the excited output molecules transfer their surplus energy to other molecules), but it also may escape as emitted light, reducing the efficiency in the use of the energy produced by an exothermic chemical reaction to less than 100% (the efficiency is also reduced when the energy of the excited molecule is transferred to other molecules than those intended, which eventually results in warming the environment instead of doing useful work).
So you're saying that there is something special about the visible spectrum? I've always wondered why most eyes we know of work in that range (modulo some leftovers from our time as aquatic creatures)
As other's commented it is "special" because a good portion of the radiation from the Sun is in the same range.
It's also special for a few other reasons. The most obvious one being that UV light is destructive to many forms of animal life, there isn't much utility in being able to see for example something like X-Rays. They don't occur naturally in any quantity and the mechanisms that create them (lightning) also give off visible light.
On the other end of things, lower energy photons are what we would call heat. Some animals can see it, but not humans. We can sense it just fine through other mechanisms however.
I invite you to consider that most of the light that earth species have had available during their evolution comes from a blackbody emitter at about 6000 kelvins (solar photosphere).
The sensitivity of the eyes is indeed matched to the available light.
However the causal dependencies are more complex than this. If the available light would have been from another range of the possible frequencies, the eyes could not have used the same kinds of photoreceptors that are used now in the eyes of all animals.
For instance, if the available light would have been only infrared, then photo-chemical reactions could not have been used for detecting it, but such light could have been detected by its warming effect, like some snakes do for detecting infrared.
If our star would have been much colder, with negligible visible light, then such light might have been not usable for splitting water and generating free oxygen in the atmosphere. In such a case, the planet would have remained populated only by anaerobic bacteria and viruses, like in the first few billion years of Earth's history.
Is there a reason why you feel compelled to compose a comment before reading or even just skimming the source? Why ask questions that are specifically answered by the provided link?
This is specifically not thermal (blackbody) radiation, which is negligible at the visible frequency range for mice at these temperatures. The researchers find a difference in visible wavelength emission between living and dead mice at the same temperature
You should post this as a top-level comment because it's extremely informative and most of everybody is just assuming this is just talking about thermal radiation.
God forbid we take something "magical" and extract the real Truth from it? Like, if this is a piece of evidence, aren't you happy to update your assumptions?
Sadly, that's not how it works. Those nutheads are twisting everything to their convenience, and sell it to idiots, even at the cost of someone's live. And any "proof" of their BS is just solidifying all the other BS.
Yes, those nutheads who are twisting it, not all nutheads who are in spiritual stuff. There are many old and ancient creeds which are barely changing for decades and centuries. Those can be also problematic, but usually their believers are more pragmatic and won't tell you how you can cure cancer by just praying hard enough while sipping the 200 dollar tea they sell you.
Sorry, I muddled together your reply and the one I originally replied to in my head and seem to have arrived at the strawman "Auras are bs and people who take this article as a hint to them are grifters/victims".
We have discovered way more exotic states of matter though. And for a preindustrial society there are only three phenomena that involve plasma: the sun, the aurora borealis, and lightning.
I don't believe in auras, but perhaps some of these photons are picked up by human brains unconsciously, even though it can not be seen "directly". Those that sense it feel special because it is not common, and may use supernatural explanations, when it is really just a natural phenomenon.
No one ever claimed that auras weren't natural, just frequencies that most people can't see. Everything vibrates, even physical matter, we've just agreed to experience some frequencies differently.
If humans could detect this light then we could see living things in otherwise complete darkness. But we cannot. So it stands to reason that these photons do not explain "auras", and "It's just your imagination" remains the best explanation for auras. Perhaps they are based on simple after-images: if you stare at something long enough the color detecting cells in your eyes get tired and you start seeing weird visual effects that seem to match how people describe "auras".
This is like saying: "Nobody can jump over this 200m wall. - Nobody is a pretty strong claim." It's really beyond the scope of human vision overall, rather than "really hard".
Or perhaps there just happened to be an overlap between the nonsense they believe in and some shred of truth that you have to squint really hard to make work.
You be more exact; I’ve spent plenty of time in internet woo-woo ideas and I don’t think I’ve heard of auras since the nineties, reading about Kirlian photographs from a hundred years before that.
Here you are saying that some unspecified group is deriving some unspecified ideas which are, you claim, life riskingly serious.
Just for the sake of making HN interesting to read, can you stop with the one sentence comments that vaguely imply you know something we don’t, and be more exact, explanatory and specific?
Frankly, IR signature + movement is more than enough to the ChatGPT+Claude+Deepseek axis to completely obliterate all those pesky electricity wasters that are not involved in useful industries like Energy and Chipmaking.
A lot of comments are assuming this is just heat.
This is specifically not thermal (blackbody) radiation, which is negligible at the visible frequency range for mice at these temperatures. The researchers find a difference in visible wavelength emission between living and dead mice at the same temperature
This point is addressed on page 2 of the paper, accessible on bioarxiv:
https://www.biorxiv.org/content/10.1101/2024.11.08.622743v1
The fact that they're seeing visible photon differences between live and dead tissue at the same temperature suggests it's tied to metabolic or biochemical activity, not just thermal noise
Yes, exactly.
I should have added that this result wasn't unexpected or mysterious as it might sound, because it's known from physics that different chemical processes have characteristic photon emissions. Since it's known that different chemical processes occur in living and dead organisms, it was expected that there would be differing emissions in the two cases. As far as I know this research is the first actual detection of these differences
I believe there's an example of something similar happening when fertilization of an egg occurs. There's a zinc reaction which creates "flash" of visible light.
Animals (and plants? Bio 101 was a long time ago) use ATP for a lot of their metabolism and phosphates are pretty well known for emitting light as they react.
Sure but, in fairness, the HN title is a bit misleading. The paper says that the bodies are emitting light in the visible part of the EM spectrum not that the light is visible. And the intensity isn't really high enough to see the light without instruments.
True, there's an ambiguity in "visible light" between "EM radiation within the visible frequency range" and "EM radiation within the visible frequency range which is of sufficient intensity that we can detect it with our eyes"
But this is independent of the misconception that the radiation observed in this experiment is thermal. Thermal radiation in the visible range at this temperature is much lower in intensity than the biological radiation observed here, but both kinds of radiation are well below the intensity that we can see with our eyes.
Sure, what isn't fair about debating the headline in the comments without reading the article?
Specifically from paper: The live/dead mice (and container) were all held at 37C, which google tells me is a normal mouse body temp. And, the observed light does not match the spectrum of black body radiation expected for the temps at which images were taken or subjects were held.
Also strange: The effect changed w/ injury or anesthetic treatment according to the abstract.
Specific electrochemical processes have their own characteristic photon emissions. Since there are some processes that occur distinctively in living organisms (e.g. to do with metabolism), it was previously thought that these would have characteristic photon emissions, but as far as I know these are the first observations of this kind of thing.
The effect changing with injury or anaesthetic I guess reflects the fact that there are different electrochemical processes occurring in these cases that have detectable differences in the photon emissions
I seem to recall the mechanism for anesthetics being something like temporarily depolarizing the mitochondrial walls to shut down ATP synthesis, so that might point towards where the effect is originating.
That would be lethal. Instead, they affect cell membranes of nerve cells.
Ah, thank you, I was misremembering. That sounds more feasible.
If we had good enough sensors could we use this for screening or diagnostics?
“Aura scanners” has an appropriately cyberpunk feel.
From the abstract the answer basically seems to be yes, and that's how they're pitching it.
They note increased emissions due to injury, which would be consistent with repair activities increasing the general intensity of chemistry happening to facilitate repair at wound sites.
Research is finding MicroTubules in the brain likely are the LINK (quantum entanglement) to where Consciousness "lives" (is located). Note that the Microtubules link STOPs while under Anesthesia.
https://www.youtube.com/results?search_query=microtubules+co...
Why does consciousness have to live somewhere? I currently prefer to think of it as an emergent phenomenon that arises (somehow, we have no clue) from the complex and distributed computations in the brain. Many different systems contribute, and saying that a single level of abstraction is where it lives seems meaningless. Kind of like saying that your video game “lives” in a transistor. It’s not wrong, but it’s not useful.
We don't seem to be able to find it inside the physical brain, and not for a lack of trying. Just throwing emergent behaviour out there changes nothing, just like it doesn't for AI.
What would "finding it" mean, whether inside the brain or out? It's quite easy to perturb consciousness by messing with the pieces of the brain, via pharmacology, injury, electrical stimulation, etc. I'm not sure why we need to assign responsibility to a single specific component like microtubules. That seems like saying the axle is responsible for a car moving. Sure, not wrong, but not right or explanatory either.
There are observed differences in brain function between conscious and unconscious patients. What's wrong with that as an initial characterization of "consciousness in the brain"? The investigation of these "neural correlates of consciousness" is quite a rich research field in its own right
Obviously, but that doesn't tell us shit where consciousness comes from.
Your idiosyncratic use of capital letters only adds to my skepticism.
Yeah he types weird and linked some generic YouTube search result that pops Joe Rogan up for some people, but there's some pretty interesting research along these lines that's becoming harder to dismiss as just Roger Penrose stepping way outta his field (I don't see people personally attacking Hameroff or Tuszynski for their roles in this research which always struck me as telling). I think it's more trying to zero in on how consciousness works from the perspective of trying to figure out how xenon administration in anesthesiology works to induce its effects.
https://www.youtube.com/watch?v=QXElfzVgg6M
https://pubs.acs.org/doi/10.1021/acs.jpcb.3c07936
https://www.sciencedirect.com/science/article/pii/S157106452...
First video when I hit that YouTube link was Joe Rogan.
Skeptic meter caught fire before I could get a reading.
This is such a weird way to navigate life.
Joe Rogan has interviewed plenty of people, different people that have very little in common, just because some of them have controversial views that make you nervous that doesn't mean all the information is useless.
We are constantly bombarded by links to information. It is reasonable to make snap judgments about the quality of the information based on who is providing it. If I’m looking for accurate, factual information on a topic that is clearly prone to magical thinking, a provider whose reputation is to listen to anyone, including people who very much engage in magical thinking, is actually a very bad source. Because they will not filter on anything beyond “is this neat to listen to.”
You are correct. However, Joe Rogan should not be the first stop for assessing the scientific plausibility of a new idea. If that is where someone is sending you, that can- and should- be a red flag.
And to add to that he's interviewed just as many absolutely mainstream scientists whose ideas are not considered controversial
Nothing weird or new about it: Suppose the foremost source for Dr. Example's claims happens to be the one time they interviewed on Coast To Coast AM [0]. That tells you something about the media-landscape they seek—or have been stuck inside.
[0] https://en.wikipedia.org/wiki/Coast_to_Coast_AM
I don't think it's the controversy of his guests so much as many of their unqualified ramblings that get treated as expertise. It's really obnoxious that it all gets put into political controversy when it's just often facially stupid BS.
And you're enough of an expert on all subjects to judge?
Or are you rather shielding from whatever makes you think?
The odd defensiveness of it wherever any criticism is labeled as some sort of philosophy against thinking.
>And you're enough of an expert on all subjects to judge?
Never claimed to be
I havent even RTFA to be fair but I like how often Bayesian heuristics like this turn out to be... Useful... If even not provably "true".
It sounds like it's time for The Talk [0].
The whole thing is good, but the final punchline in the last three panels are particularly relevant.
[0] https://www.smbc-comics.com/comic/the-talk-3
Pretty much everything that is either capturing or releasing energy is giving off a spectrum of EM radiation. Usually it is mostly in the IR range, but you really just need sensitive enough equipment to get all sorts of EM noise.
Not "pretty much everything" but actually everything. The only way an object wouldn't emit radiation is if it was at absolute zero, which is something that exists literally no where in the universe.
That said, this light is not the result of just radiating heat and must have a different source.
Guessing these are surfacing due to the recent Radiolab podcast "The Spark of Life": https://radiolab.org/podcast/the-spark-of-life
> in the spectral range of 200–1000 nm
That's UV, visible and near IR. We know that 100-600 nm (infrared EDIT: UV) light "can carry out photostimulation and photobiomodulation effects particularly benefiting neural stimulation, wound healing, and cancer treatment" [1]. I'm curious what could be producing UV and visible light.
Does light production tend to hang out around any particular organs or organelles? If stress causes it, I'd hypothesise it's metabolic or signalling related.
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC5505738/
> 100-600 nm (infrared) light
Ultraviolet, you mean.
> I'm curious what could be producing UV and visible light.
There is tons of chemoluminescent stuff in a live being. As my spectroscopist friend says, everything luminesces at some point.
I would assume respiratory complexes I and III in mitochondria. Both used highly reduced states to create the gradient to pump protons, and electron leakage is inevitable.
This likely then leads to redox transitions in quinones, flavins, metal centres, leaving them in unstable excited states. When they relax, the excess energy has to go somewhere - usually thermal energy, but just occasionally, a photon.
This would also tally with anaesthetics and injury having an effect, as both effect mitochondrial function - and of course when you’re dead, so are your mitochondria.
Thanks, that's the first thought I had, thanks for reporting mitochondria. Which are not localized stuctures as pictured in undergrad courses.
Yes, I come here to mention that this phenomena has something to do with mitochondria.
For the next decade it most probably will be one of the very important topics in science of life in general.
The brain is electro-chemical, hold all sorts of minuscule charges… I guess once the process for keeping that all going comes to abrupt halt, electric potentials change which would take into account some electromagnetic field :shrugs:
I listened to the Radiolab podcast. I remained fairly unconvinced by the reporting on the show, but the part that really didn't make sense to me was, what is their definition of death? My (limited, non-medical) understand is that death has a bit of a spectrum associated with it. At what point does this light stop emitting? When you flatline exactly?
I came here with a similar thought. Given that we don't have a really precise definition of that transition from living to dead, I wonder if this could be it.
Some parts of the dead mice still emit in that spectrum. There won't be a clear and distinct "the lights went out" moment but a gradual fading, so you'll have to define some threshold to translate from radiation distribution and intensity do dead/alive. I don't think an image of photon emission will help pronounce someone dead.
I mean the definition of death is when the light fades right? Everything else is just an approximation. Would be wild if true.
Light is just a form of electromagnetic radiation. All processes produce electromagnetic radiation, only different in the amount. So as we improve our equipments, we naturally can see more things like that.
"See" is a poor verb choice. "Detect".
Finally a way we can do the Star Trek "scanning for life forms".
I just love scanning for life forms.
https://www.youtube.com/watch?v=dWBmaKk32fE
He's dead, Jim.
I'm a doctor, not a spectrophotometer!
Title: Imaging Ultraweak Photon Emission from Living and Dead Mice and from Plants under Stress
Previously (19 points, April) https://news.ycombinator.com/item?id=44617867
How soon after death does it expire? Are we talking seconds? Hours?
Exactly 21 moments.
Imperial or metric?
Yes.
When the soul leaves the body.
I couldn't get to the PDF.
Here are articles commenting some of the content:
https://nrc.canada.ca/en/stories/worlds-first-ultraweak-phot...
https://www.sciencealert.com/we-emit-a-visible-light-that-va...
https://phys.org/news/2025-05-emit-faint-extinguishes-death....
Kind of makes you wonder if this could eventually become a diagnostic tool, though I imagine the sensitivity requirements and ambient light issues are pretty brutal in real-world settings
When you get dental X-rays, the technician aligns the instrument and leaves the room to push the button that triggers the image capture.
Another problem to solve though, is ignoring the E-M radiation from small life forms that may be in the room.
“Pause CPR and turn off all the lights.”
Isn’t it well known you can tell plant health via there spectral return? NVDI cameras/filters?
https://static.publiclab.org/#wiki/ndvi
The difference here being absorption vs. emission I guess?
TIL local anesthetics works on plants
https://medium.com/@lukehollomon/anesthesia-works-on-plants-...
You might enjoy The Light Eaters, it covers latest studies on plants for consciousness. I’m still very skeptical after reading it, I.e. how to differentiate between automaton like behavior derived from genetic programming and consciousness (argued for in the book) is still not clear to me.
I find it totally inline with expectations that, given sufficiently accurate measurement aparatus, one could detect a difference in light (and sound, and moves, and smell...) between living, stressed or dead things. After all, those are very distinguishable state of matter.
Does this mean we can finally answer the question "at what point is a strawberry no longer alive"?
As someone wise once said, “You just gotta ignite the light and let it shine”
Turns out Katy Perry was low-key talking about ultraweak biophoton emission all along
Luminous beings are we, not this crude matter.
We use a lot of energy, its not surprising we emit it.
It is surprising to me that it is in the visible range.
The visible range corresponds to the typical energy differences between different states of an outer electron in a molecule, which also correspond to the typical energy differences between the input and output molecules of a chemical reaction.
(The near infrared range corresponds to the typical energy differences between different vibrational states of the atoms in a molecule. Such energy differences are smaller than the energy differences encountered in most chemical reactions, which involve extracting or adding atoms from/to the molecule, which obviously needs more energy than the vibration of those atoms, when they remain bound in the molecule.)
Thus it is normal and expected that the output molecules of an exothermic chemical reaction may be in an excited state from which they can decay to their ground state by emitting light exactly in the visible range.
As long as it is living, in any organism a lot of exothermic chemical reactions happen. In many cases the energy produced by those reactions is used for something useful for the organism (i.e. the excited output molecules transfer their surplus energy to other molecules), but it also may escape as emitted light, reducing the efficiency in the use of the energy produced by an exothermic chemical reaction to less than 100% (the efficiency is also reduced when the energy of the excited molecule is transferred to other molecules than those intended, which eventually results in warming the environment instead of doing useful work).
Hooold up.
So you're saying that there is something special about the visible spectrum? I've always wondered why most eyes we know of work in that range (modulo some leftovers from our time as aquatic creatures)
As other's commented it is "special" because a good portion of the radiation from the Sun is in the same range.
It's also special for a few other reasons. The most obvious one being that UV light is destructive to many forms of animal life, there isn't much utility in being able to see for example something like X-Rays. They don't occur naturally in any quantity and the mechanisms that create them (lightning) also give off visible light.
On the other end of things, lower energy photons are what we would call heat. Some animals can see it, but not humans. We can sense it just fine through other mechanisms however.
You're missing a big one: organic chemistry* changes often occur in the 4-7 eV range of energy, which is the visible spectrum.
* Meaning "molecules containing carbon", not "hippy chemistry done without pesticides".
I invite you to consider that most of the light that earth species have had available during their evolution comes from a blackbody emitter at about 6000 kelvins (solar photosphere).
https://www.sciencedirect.com/topics/physics-and-astronomy/s...
The sensitivity of the eyes is indeed matched to the available light.
However the causal dependencies are more complex than this. If the available light would have been from another range of the possible frequencies, the eyes could not have used the same kinds of photoreceptors that are used now in the eyes of all animals.
For instance, if the available light would have been only infrared, then photo-chemical reactions could not have been used for detecting it, but such light could have been detected by its warming effect, like some snakes do for detecting infrared.
If our star would have been much colder, with negligible visible light, then such light might have been not usable for splitting water and generating free oxygen in the atmosphere. In such a case, the planet would have remained populated only by anaerobic bacteria and viruses, like in the first few billion years of Earth's history.
Yeah, I always unconsciously assumed it's just a random slice, never thought deeper about this. Thanks, HN!
This is a lot to chew on. Thank you.
Every body does emit radiation. Most is in IR range, but since nature is very broad, a very small amount is in a wide band from the spectrum.
https://en.m.wikipedia.org/wiki/Black-body_radiation
You can see it in the picture, the radiation is very wide.
You'll probably want to compare/contrast that with Fig 1 in the paper https://www.biorxiv.org/content/10.1101/2024.11.08.622743v1....
If you can see something with your biological eyes, it is emitting energy in the electromagnetic spectrum
I don't know about you, but I have trouble seeing other life forms in a room that is pitch black.
I don’t know what my comment had to do about being in a situation where you don’t see it
More likely to be reflecting, not emitting.
Which is actually the same.
Simple experiment: Turn off the lightbulb, close the curtains and check again how many of your household items are still "emitting" light.
When I provide the necessary energy with the necessary frequency they will.
transforming food into energy and poop seems to be the meaning of life from an individual point of view
The second law of thermodynamics! Life is the ultimate expression of that. We create order, but to do that we always create more chaos than order.
"Luminous beings are we; not this crude matter"
- Yoda
Can we detect it on exoplanets?
No. If it's barely detectable right next to the organism, it's extremely below the noise level on a planetary scale.
What if we got 8 billion people to all jump, er, bio-luminate at once?
You'd still get less than 1 cd of luminance in total, unless my napkin math is way off.
This must be the light my supermarket uses to make meat look fresh.
Was "AI" used in this study?
why does it feel like the world is full of "explainers" and "rationalisers"
usually unintentionally pushing the accepted narrative
anytime something interest comes up everyone seems to try to downplay or explain it
the fact is even your explanation is wrong on some level
Is that just heat?
The source specifically tells you the answer.
You’re all made of stars you gotta let that shit shine okay?
..so black-body radiation?
Is there a reason why you feel compelled to compose a comment before reading or even just skimming the source? Why ask questions that are specifically answered by the provided link?
You can only access the abstract without logging in and I see no argument that this isn't black-body radiation in that.
no
thats because they are npc's
I prefer to call it heat. Just to clarify the picture.
This is specifically not thermal (blackbody) radiation, which is negligible at the visible frequency range for mice at these temperatures. The researchers find a difference in visible wavelength emission between living and dead mice at the same temperature
This point is addressed on page 2 of the paper.
Paper is accessible on bioarxiv: https://www.biorxiv.org/content/10.1101/2024.11.08.622743v1
You should post this as a top-level comment because it's extremely informative and most of everybody is just assuming this is just talking about thermal radiation.
Done ^^
>visible light
I thought black bodies emitted light the whole spectrum, albeit with differences in the distribution depending on their temperature?
Yep, but the exponential decay at the short-wavelength end means you're going to hit a single-digit number of photons/m^2/s fairly quickly.
> 10–10^3 photons cm^–2 s^–1
So probably invisible but under the very darkest of conditions?
Visible refers to being in the visible spectrum.
Oh no, this will feed the "aura" BSers
God forbid we take something "magical" and extract the real Truth from it? Like, if this is a piece of evidence, aren't you happy to update your assumptions?
Sadly, that's not how it works. Those nutheads are twisting everything to their convenience, and sell it to idiots, even at the cost of someone's live. And any "proof" of their BS is just solidifying all the other BS.
You have a one-dimensional view of your "opponents". Not everybody who is into spiritual BS is preying on suckers, or a sucker being preyed upon.
The thinking that preceded our current understanding of physical elements was very loose and woo-woo(Water, Earth, Wind, Fire), but we refined.
I never claimed that everyone is doing this. Are you reflecting?
You did though. You said "those nutheads". Not "some of those nutheads"
Yes, those nutheads who are twisting it, not all nutheads who are in spiritual stuff. There are many old and ancient creeds which are barely changing for decades and centuries. Those can be also problematic, but usually their believers are more pragmatic and won't tell you how you can cure cancer by just praying hard enough while sipping the 200 dollar tea they sell you.
Sorry, I muddled together your reply and the one I originally replied to in my head and seem to have arrived at the strawman "Auras are bs and people who take this article as a hint to them are grifters/victims".
I guess it's a charged topic for me (badumm-tss).
Solid, liquid, gas, and plasma fit the woo-woo explanation of earth, water, air, and fire quite well though. It's actually eerie how well it fits.
We have discovered way more exotic states of matter though. And for a preindustrial society there are only three phenomena that involve plasma: the sun, the aurora borealis, and lightning.
Fire is not a state of matter, it's a process. Sadly, my prog rock band "Solid Gas and a Process that Creates Heat and Light" never really took off.
Liquid is not literally only water either, so I don't think it contradicts the comparison.
Hey, never thought of it like that!
I don't believe in auras, but perhaps some of these photons are picked up by human brains unconsciously, even though it can not be seen "directly". Those that sense it feel special because it is not common, and may use supernatural explanations, when it is really just a natural phenomenon.
No one ever claimed that auras weren't natural, just frequencies that most people can't see. Everything vibrates, even physical matter, we've just agreed to experience some frequencies differently.
That one has to use a throwaway to avoid losing HN good boy points from the bitter fedora-posters is a shame.
Yup, could be! My problem is not with that, but rather the things they seem to "derive" from this.
If humans could detect this light then we could see living things in otherwise complete darkness. But we cannot. So it stands to reason that these photons do not explain "auras", and "It's just your imagination" remains the best explanation for auras. Perhaps they are based on simple after-images: if you stare at something long enough the color detecting cells in your eyes get tired and you start seeing weird visual effects that seem to match how people describe "auras".
Corollary: it'll give the materialism jerks something to think about.
such as?
That perhaps the people who claim to see auras were in fact telling the truth due to having the right genetics to be able to observe this light.
They don't. It's normal visible light spectrum, just extremely weak. Nobody can see it with their eyes.
Supposedly the human eye can detect a single photon under the right conditions though.
Not really... https://www.technologyreview.com/2017/08/08/105518/the-thorn...
Or, yes, under ideal conditions, maybe sometimes. 51.6% chance of being right in a yes/no question will not help in this case.
Nobody is a pretty strong claim.
Human bodies are different in many ways.
This is like saying: "Nobody can jump over this 200m wall. - Nobody is a pretty strong claim." It's really beyond the scope of human vision overall, rather than "really hard".
Those are ... two different things?
People can pick up single photons, this is definitely within the realm of possibility.
Btw, your level zero snark can be defeated by the "on which planet?" argument.
Or perhaps there just happened to be an overlap between the nonsense they believe in and some shred of truth that you have to squint really hard to make work.
That's not even the "BS" part (for me), but what they "derive" from all of that.
Such as, maybe there's more to life than just chemical reactions.
Where is the indication that this light (which is barely visible to instruments, let alone humans) does not come from "just chemical reactions"?
This finding is certainly interesting, but it does not at all contribute to "spiritual thinking".
Bioluminescence IS a natural chemical reaction, though.
Are you implying the light discussed in the paper is supernatural?
More, how? Come on, be more exact.
You be more exact; I’ve spent plenty of time in internet woo-woo ideas and I don’t think I’ve heard of auras since the nineties, reading about Kirlian photographs from a hundred years before that.
Here you are saying that some unspecified group is deriving some unspecified ideas which are, you claim, life riskingly serious.
Just for the sake of making HN interesting to read, can you stop with the one sentence comments that vaguely imply you know something we don’t, and be more exact, explanatory and specific?
no ;)
This is the technology Skynet will harvest to track down and eliminate all life. Finally an objective and measurable metric for this pesky concept!
Frankly, IR signature + movement is more than enough to the ChatGPT+Claude+Deepseek axis to completely obliterate all those pesky electricity wasters that are not involved in useful industries like Energy and Chipmaking.
Perhaps this is why creatures keep evolving eyes.
Woah that's wild, so this gives credence to some more spiritual stuff out there.