The sun is so large I bet all kinds of unlikely phenomena are possible at small scales. If there was life on the sun, would be know it or recognize it?
It's easy to notice carbon/water life because we are it, but most of our complexity exist within a rather narrow energy band (molecular electron orbitals with energy greater than a C-O and less than a C-H), so I think you're right to doubt that we'd recognize if there were a similarly narrow window into surprising complexity in the nuclear reactions that take place within the sun.
I expect there's quite a lot of "life" that we're overlooking, and that we're going to feel quite silly when we have whatever encounter causes us to broaden our definitions to include the rest of it.
Although to be pedantic, most definitions of life require that it be made of cells, and I doubt there are anything like cells in the sun.
Most definitions of life are very arbitrary. When it comes to astrobiology, we mostly look for things that look like us because if we didn't, the search space would be incomprehensibly large and frankly there's not a lot we could say.
Yeah definitions are tricky. If you saw a house consumed with fire, you might look at the circumstances and conclude that it was likely the offspring of the fire that consumed the house across the street, but there wouldn't be anything about the fire's phenotype that would help you come to that conclusion.
If the flames carried the characteristic shape of their parents fire, and they could be distinguished as not the offspring of some other fire by their features alone, then I'd be arguing that fire is alive.
I feel like I'm at risk of classifying certain periodic crystals as alive here, but they wouldn't meet the thermodynamic requirements that I have in mind (which fire does meet).
You made me remember how I was ridiculed by my teacher by asking if there was a possibility that life could be based on other thing than carbon. Granted, as I grew older and learnt a little bit more about the chemistry of carbon I realized that it had almost magic properties for life, but I wondered for long time why he reacted that way.
Ridiculing genuine curiosity is a terrible behavior from teachers... why stifle inquisitive minds? Anyway, you may already be familiar with these proposed biochemistries, but there has been a lot of speculation on this exact question over the years:
You probably triggered some memory. Perhaps, a student who insisted they knew more than the teacher and pushed some ignorant argument too far... so when you suggested the idea, and perhaps tried to push a bit more consideration, the teacher found himself re-living that bad experience and treated you like you were the other student, even if you yourself didn't push the matter beyond an acceptable level.
Silicon has almost the exact same properties as carbon. At high temperatures, carbon chains can’t form, but silicon chains can. In a high-temperature or high-pressure range, silicon might for a basis for life, analogous to carbon for us. So, not only was that question not stupid, it was profound.
Look at silicon on the periodic table. All of the things that make carbon great, basically silicon has almost exactly, except it needs a high temperature for most of those properties to be expressible.
That teacher didn’t know what he was talking about. Ridiculing a student for questions is such detestable behavior. The silliest questions can end up being the most insightful. I really despise teachers like that.
Here is a paper all about how your question was actually wonderful.
Silicon has only superficial similarities to carbon. Even at high temperatures, water and oxygen prevent silicon from substituting for carbon in any of what we are familiar with as organic molecules.
Your linked paper points out that the only viable solvent that supports a large variety of silicon chemistry is sulphuric acid, and even then it would need to be very poor in oxygen since silicon-oxygen bonds are so strong it ends up being much more strongly preferred over si-si bonds.
It makes for an interesting conversation, but I can't imagine spending an entire class going over what amounts to a massive distraction from the lesson plan.
All that's left is going to amount to an effectively dismissive answer, I suppose (though I agree that teachers who are intentionally dismissive are doing it wrong).
Wouldn’t an environment that has a significant sulfuric acid content naturally also a relatively limited free oxygen?
I’m thinking of Venus. That sort of environment would satisfy all criteria and would also start to get into the temperature ranges that would make Si-Si bonds possible.
That would at-least bracket the types of planets and their history to a useful extent.
Sulphuric acid actually has a lot of oxygen and hydrogen in it, and the presence of any metal or even high enough temperature will cause it to break up.
In a lab, it makes for a good solvent, but any place that has sulphuric acid will have both water and oxygen.
Venus, notably, has little to none of both. What free oxygen that does exist is from CO2 and CO breaking down in the atmosphere from the intense and extended venusian day. Most of the sulphur on Venus is sulphur dioxide (a tiny percentage of the atmosphere), and water vapor is a measly 20ppm.
Even if all of that water was sulphuric acid (which it may well be), there's simply not enough of it staying still long enough to form the repeating patterns of chemistry that might reasonably be called life.
Boron and Nitrogen may have a chance. They form long weird molecules that are stable. Is it possible? I don't know. Can they compeat with Carbon base life? Perhaps no. In a weird planet where almost all the Carbon is sequestred by some weird chemical composition of thee rocks, can Boron or Nitrogen life have a chance. I don't know!
(My guess is that we still need a few thousand years to answer these questions. We still don't understand too may details about Carbon based life. I'm not very optimistic.)
I wonder to what extent they'd need to compete at all, they'd probably have a different diet. Maybe there are carbon life forms out there living mutualistically with boron-nitrogen life forms.
I don't expect a mix of Boron and Nitrogen. Only Boron in some planets and only Nitrogen in another planets.
We [1] can eat things with Nitrogen, so I expect a competing form to be completely eaten if they are less effecient.
I don't know enough about Boron chemistry, but if there were enough of them we will eat them too, unles they eat us first.
The first stages of living things are probably very ineficient. If you need a year to make a viable copy, a previus life form will probably eat you before that. I think that two independent origins of life in tha same planet are impossible.
[1] If you include bacteria and archea in "we". And even we (humans) can eat some compound with nitrogen, in particular proteins that mix carbon and nitrogen.
Boron is scarce; it's one of the x-process elements, and those inherently have low abundance (although the boron-to-carbon ratio in the Earth's crust is enhanced over the solar system ratio, I believe.)
Boron nitride is weirdly analogous (indeed, isoelectronic) to carbon in that there's a graphite-like form (hexagonal BN) and a diamond-like form (cubic BN).
One thing that would hold back BN life is that by themselves B and N form more stable compounds than carbon does. Nitrogen in particular forms molecular nitrogen, which is annoyingly tightly bound.
> most definitions of life require that it be made of cells
Does this animal has cells? https://en.wikipedia.org/wiki/Xenophyophorea I feel like answering yes and calling it "unicelular" is cheating, but it's clear that it evolved from animals with cells and it has only "one".
It's a cell, but the (informal) idea is that a big living thing is made of a lot of small cells. If there is a catastrofic extintion and only these things survive, would and alien biologist clasify them as a huge cell or as a blob?
> How is it clear that it evolved from animals? It seems like clear protist to me.
My bad. You are right. I probaly mean from a normal living thing with small cells with only one nuclei.
> Skeletal muscle fibers are made when myoblasts fuse together; muscle fibers therefore are cells with multiple nuclei, known as myonuclei, with each cell nucleus originating from a single myoblast. The fusion of myoblasts is specific to skeletal muscle, and not cardiac muscle or smooth muscle.
In the polar regions of the Sun where the surface temperatures might be lower....
/jk
On a serious note scientists have long been able to measure that the sun has a large amount of energy available to any possible inhabitants. Until we understood enough physics around plasmas and the composition of stars it makes perfect sense to hypothesise the existence of creatures/life that would be able to utilise that energy for their own version of high temperature life. To be clear, I think that the extreme conditions in every part of the Sun preclude any possibility of life or life like processes.
A lack of understanding of plasma dynamics isn't preventing construction of a useful fusion reactor. Other energy sources being cheap and construction costs being high are much larger limitations.
We could have built a scaled up steady state tokamak using pure D-D fusion all the way back in the 1990's. We didn't because coal, fission, etc where plentiful/cheap and nobody was going to waste a trillion dollars on such technological dead end.
The current technical challenges are all about bring the costs down. Designing and using a breeding blanket is far more complected than a steel wall, but D-T allows for a vastly smaller and therefore hopefully much cheaper device.
tokamak researchers generally do not agree with you
the humans only achieved breakeven in 02022, and not in a tokamak, but in an inertial confinement experiment, which is to say, a tiny bomb. thinking you need a trillion dollars is a symptom of not knowing how to do it; the trillion dollars are to spend on experiments
Actually that trillion dollar number was from a Tokamak researcher. Though I am not sure how serious they where being when using it.
With Tokamak's Q isn't a constant for a general design it's a result of scaling laws and a specific size thus ITER was chosen at Q >= 10 but they could have picked bigger or smaller target. EX: https://nucleus.iaea.org/sites/fusionportal/Shared%20Documen...
In 1997 JET hit an equivalent Q of 0.67 using a 3m by 1.25m device and D-T. You can look at costs and scaling factors along with the output of DD vs DT fusion. I took a trillion dollar budget just mean ~10,000x the cost of JET which seems to line up reasonably well. Though making such a large jump in scale would have it's own challenges.
It's also always been possible to reach breakeven (and above) in magnetic mirrors. These are linear devices that leak out the ends, so just make them long enough and they will reach breakeven. The problem has been "long enough" has been "kilometers".
How we would call such depends how you define and understand life. If one defines it very widely as a dynamic dissipative process in an open thermodynamic system which organizes matter and energy, reacts to its surroundings, can reproduce itself, may have some symbolic representation of its surroundings, and possibly even care for its reproductions, intelligent life on a star is entirely possible, even if it would be very, very different from us.
If you on the other hand, define it as a set of dissipative structures which are based on organic carbon chemistry and which is able to exist somewhere between -30 and 40 degrees centigrade, replicates itself, use Deoxyribonucleic acid to store generational information, nourish their young by mammary glands, and walk on two legs, we are probably pretty alone in the universe.
Another things to think about, all life forms on our planet are relatives in the sense that we have common ancestors and shared DNA, even such "alien" creatures like tarantulas or centipedes. Given that, I am not entirely sure that it would be pleasant for us to meet technologically superior aliens. We would have to pray that they have much more empathy with other living things than we primates ourselves can usually muster.
"If you on the other hand, define it as a set of dissipative structures which are based on organic carbon chemistry and which is able to exist somewhere between -30 and 40 degrees centigrade, replicates itself, use Deoxyribonucleic acid to store generational information, nourish their young by mammary glands, and walk on two legs, we are probably pretty alone in the universe."
I have heard arguments that all life must be carbon based, and the temperature range is really a proxy argument for life requiring h2o. Everything after dna is clearly a joke.
It's yonks since I read it, but IIRC Olaf Stapledon's Star Maker (1937) played with (alongside everything else) the idea of stars as life-forms themselves.
I'd strongly recommend it; it's very weird and obviously quite dated, but nothing else ever written even comes close for sheer ambition.
I'll save you the reading, as he doesn't provide any evidence for the proposition. He merely speculates on what it might mean for the sun to be conscious. Also he's way out there on the wacky scale. I sank a lot of time reading his works as an undergraduate, as they're couched in quite scientific terms and he claims to have conducted rigorous experiments. But the more you look into the experiments, the more methodological flaws you find, and eventually I decided it wasn't worth the effort.
Robert Forward wrote a series of sci-fi novels about life on the surface of a neutron star. The first was called Dragon's Egg [1] and is a decent, if tropey, read. Some of the same issues are addressed in his books, of course making a ton of assumptions about the properties of neutron star matter (we still don't know the equation of state for neutron stars).
The idea is very simply that combining abundant energy with something capable of holding structure in such an environment could in theory produce a persistent store of information. A leap, sure, but a fun one.
Stanisław Lem wrote a story about a trio of scientists who recreate Sun's environment in a lab and discover it supports life & evolution which goes zero to sun-worm in the time it takes for the experiment to blow up, implying existence of lifeforms inside the Sun so advanced that they just don't bother to communicate with humans.
> The idea is very simply that combining abundant energy with something capable of holding structure in such an environment could in theory produce a persistent store of information. A leap, sure, but a fun one.
Hardly? We know that structures on the sun are capable of being (somewhat) persistent, and not only that, but even doing something vaguely resembling computation. Solar magnetic fieldlines are long-lived, producing visible sunspots that not only last for potentially several months, but show variations in frequency over a largely stable 11-year clock/cycle (during which the entire solar magnetic field flips/behaves as a binary oscillator). Magnetohydrodynamics is famously complex and capable of metastable configurations, and we don't know exactly what happens under the photosphere, but I don't think anybody could really argue that there isn't enough physical space and raw energy to swallow up every personal and animal on Earth.
Really, for all we know, I think the sun itself might be alive/sentient. Or maybe it contains not physically embodied life, but isolated engrams and memes styled after Boltzmann brains, something analogous to crystal structures (which self-proliferate/grow) but with more complexity. The question is whether there's any way to decode/decrypt the information that definitely is there— complex heterogeneous distributions over time in field strength, temperatures, convection patterns, etc.— into any form that isn't just repetition plus random noise.
I guess the issue is that you don't really know why you're conscious. If you had never seen a brain before, you would just think it was a useless blob of chaotically arranged fat. And even if you did know why you're conscious, you still wouldn't be able to say that that's the only way your specific form of consciousness can arise, nor that there aren't any other completely alien but equally conscious types of minds. Hell, homomorphic encryption means that it can be mathematically impossible to know whether any given complex system is just random noise, or contains someone's memories, experiences, desires, a soul. So given any system of adequate complexity, without knowing enough about it to put definite constraints on what it can do, I don't see how you could say for sure that it isn't "alive"/sentient.
When I hit my early teens, the example I thought of was n-body gravitational perturbations in something like the asteroid belt, and something like crystal grain structures in regular solid matter.
…Sucks for the lack of opposable thumbs, I guess, if it is alive. The information which may or may not be encoded in the sun may have unknown complexity and meaning, but I feel much more confident in saying that the amount of precision carried out by the solar wind and solar radiation will never allow it to shape and navigate the world around it like we can ours.
One generally accepted feature of life is maintaining a localized entropy anomaly, at the expense of dumping excess heat to an outside reservoir. There is no evidence that the Sun is doing anything like that. All of its MHD processes follow normal laws of thermodynamics, where structures will persist at a variety of scales and durations according to universal power-law spectra. The gravitational dynamics of the asteroid belt definitely doesn't exhibit any entropy peaks not explained by Jovian perturbations, etc.
I think you are confusing statistically improbable, but completely normal, patterns with meaningful ones, which is probably the primary flaw of the human brain.
That said, it's also improbable that our meat brains can comprehend every possible form of life in the universe.
The future sun, yes. The current sun is far, far too dense, which would make it cataclysmic (dramatically more energy released than Shoemaker-Levy 9) for the Earth to be inside of the sun.
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[ 2.8 ms ] story [ 75.2 ms ] threadI expect there's quite a lot of "life" that we're overlooking, and that we're going to feel quite silly when we have whatever encounter causes us to broaden our definitions to include the rest of it.
Although to be pedantic, most definitions of life require that it be made of cells, and I doubt there are anything like cells in the sun.
Is there a deeper reason for that?
I'd rather exclude fire on the basis that it's "reproduction" involves nothing like heritability.
I do know what you're saying but it's so easy to argue the other way too
If the flames carried the characteristic shape of their parents fire, and they could be distinguished as not the offspring of some other fire by their features alone, then I'd be arguing that fire is alive.
I feel like I'm at risk of classifying certain periodic crystals as alive here, but they wouldn't meet the thermodynamic requirements that I have in mind (which fire does meet).
> but there wouldn't be anything about the fire's phenotype that would help you come to that conclusion
but... but... cloning!
But yes, we could do this all day and still get nowhere. We, collectively, are missing something but I don't know what.
https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...
It happens to the best of us.
Look at silicon on the periodic table. All of the things that make carbon great, basically silicon has almost exactly, except it needs a high temperature for most of those properties to be expressible.
That teacher didn’t know what he was talking about. Ridiculing a student for questions is such detestable behavior. The silliest questions can end up being the most insightful. I really despise teachers like that.
Here is a paper all about how your question was actually wonderful.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7345352/
Your linked paper points out that the only viable solvent that supports a large variety of silicon chemistry is sulphuric acid, and even then it would need to be very poor in oxygen since silicon-oxygen bonds are so strong it ends up being much more strongly preferred over si-si bonds.
It makes for an interesting conversation, but I can't imagine spending an entire class going over what amounts to a massive distraction from the lesson plan.
All that's left is going to amount to an effectively dismissive answer, I suppose (though I agree that teachers who are intentionally dismissive are doing it wrong).
I’m thinking of Venus. That sort of environment would satisfy all criteria and would also start to get into the temperature ranges that would make Si-Si bonds possible.
That would at-least bracket the types of planets and their history to a useful extent.
In a lab, it makes for a good solvent, but any place that has sulphuric acid will have both water and oxygen.
Venus, notably, has little to none of both. What free oxygen that does exist is from CO2 and CO breaking down in the atmosphere from the intense and extended venusian day. Most of the sulphur on Venus is sulphur dioxide (a tiny percentage of the atmosphere), and water vapor is a measly 20ppm.
Even if all of that water was sulphuric acid (which it may well be), there's simply not enough of it staying still long enough to form the repeating patterns of chemistry that might reasonably be called life.
(My guess is that we still need a few thousand years to answer these questions. We still don't understand too may details about Carbon based life. I'm not very optimistic.)
We [1] can eat things with Nitrogen, so I expect a competing form to be completely eaten if they are less effecient.
I don't know enough about Boron chemistry, but if there were enough of them we will eat them too, unles they eat us first.
The first stages of living things are probably very ineficient. If you need a year to make a viable copy, a previus life form will probably eat you before that. I think that two independent origins of life in tha same planet are impossible.
[1] If you include bacteria and archea in "we". And even we (humans) can eat some compound with nitrogen, in particular proteins that mix carbon and nitrogen.
Boron nitride is weirdly analogous (indeed, isoelectronic) to carbon in that there's a graphite-like form (hexagonal BN) and a diamond-like form (cubic BN).
One thing that would hold back BN life is that by themselves B and N form more stable compounds than carbon does. Nitrogen in particular forms molecular nitrogen, which is annoyingly tightly bound.
Does this animal has cells? https://en.wikipedia.org/wiki/Xenophyophorea I feel like answering yes and calling it "unicelular" is cheating, but it's clear that it evolved from animals with cells and it has only "one".
Seems like a cell to me? How is it clear that it evolved from animals? It seems like clear protist to me.
It's a cell, but the (informal) idea is that a big living thing is made of a lot of small cells. If there is a catastrofic extintion and only these things survive, would and alien biologist clasify them as a huge cell or as a blob?
> How is it clear that it evolved from animals? It seems like clear protist to me.
My bad. You are right. I probaly mean from a normal living thing with small cells with only one nuclei.
---
Side note: I'm not sure it's related, but as a curiosity, our muscles have cells with multiple nuclei https://en.wikipedia.org/wiki/Muscle_cell
> Skeletal muscle fibers are made when myoblasts fuse together; muscle fibers therefore are cells with multiple nuclei, known as myonuclei, with each cell nucleus originating from a single myoblast. The fusion of myoblasts is specific to skeletal muscle, and not cardiac muscle or smooth muscle.
/jk
On a serious note scientists have long been able to measure that the sun has a large amount of energy available to any possible inhabitants. Until we understood enough physics around plasmas and the composition of stars it makes perfect sense to hypothesise the existence of creatures/life that would be able to utilise that energy for their own version of high temperature life. To be clear, I think that the extreme conditions in every part of the Sun preclude any possibility of life or life like processes.
We could have built a scaled up steady state tokamak using pure D-D fusion all the way back in the 1990's. We didn't because coal, fission, etc where plentiful/cheap and nobody was going to waste a trillion dollars on such technological dead end.
The current technical challenges are all about bring the costs down. Designing and using a breeding blanket is far more complected than a steel wall, but D-T allows for a vastly smaller and therefore hopefully much cheaper device.
the humans only achieved breakeven in 02022, and not in a tokamak, but in an inertial confinement experiment, which is to say, a tiny bomb. thinking you need a trillion dollars is a symptom of not knowing how to do it; the trillion dollars are to spend on experiments
With Tokamak's Q isn't a constant for a general design it's a result of scaling laws and a specific size thus ITER was chosen at Q >= 10 but they could have picked bigger or smaller target. EX: https://nucleus.iaea.org/sites/fusionportal/Shared%20Documen...
In 1997 JET hit an equivalent Q of 0.67 using a 3m by 1.25m device and D-T. You can look at costs and scaling factors along with the output of DD vs DT fusion. I took a trillion dollar budget just mean ~10,000x the cost of JET which seems to line up reasonably well. Though making such a large jump in scale would have it's own challenges.
https://thereader.mitpress.mit.edu/the-truth-by-stanislaw-le...
If you on the other hand, define it as a set of dissipative structures which are based on organic carbon chemistry and which is able to exist somewhere between -30 and 40 degrees centigrade, replicates itself, use Deoxyribonucleic acid to store generational information, nourish their young by mammary glands, and walk on two legs, we are probably pretty alone in the universe.
Another things to think about, all life forms on our planet are relatives in the sense that we have common ancestors and shared DNA, even such "alien" creatures like tarantulas or centipedes. Given that, I am not entirely sure that it would be pleasant for us to meet technologically superior aliens. We would have to pray that they have much more empathy with other living things than we primates ourselves can usually muster.
No one would define life this way.
https://www.mpg.de/20074327/extraterrestrial-intelligence-qu...
The idea didn't die, it grew to an unrecognizable size.
I'd strongly recommend it; it's very weird and obviously quite dated, but nothing else ever written even comes close for sheer ambition.
https://www.sheldrake.org/files/pdfs/papers/Is_the_Sun_Consc...
I'll save you the reading, as he doesn't provide any evidence for the proposition. He merely speculates on what it might mean for the sun to be conscious. Also he's way out there on the wacky scale. I sank a lot of time reading his works as an undergraduate, as they're couched in quite scientific terms and he claims to have conducted rigorous experiments. But the more you look into the experiments, the more methodological flaws you find, and eventually I decided it wasn't worth the effort.
The idea is very simply that combining abundant energy with something capable of holding structure in such an environment could in theory produce a persistent store of information. A leap, sure, but a fun one.
1. https://en.wikipedia.org/wiki/Dragon%27s_Egg
Hardly? We know that structures on the sun are capable of being (somewhat) persistent, and not only that, but even doing something vaguely resembling computation. Solar magnetic fieldlines are long-lived, producing visible sunspots that not only last for potentially several months, but show variations in frequency over a largely stable 11-year clock/cycle (during which the entire solar magnetic field flips/behaves as a binary oscillator). Magnetohydrodynamics is famously complex and capable of metastable configurations, and we don't know exactly what happens under the photosphere, but I don't think anybody could really argue that there isn't enough physical space and raw energy to swallow up every personal and animal on Earth.
Really, for all we know, I think the sun itself might be alive/sentient. Or maybe it contains not physically embodied life, but isolated engrams and memes styled after Boltzmann brains, something analogous to crystal structures (which self-proliferate/grow) but with more complexity. The question is whether there's any way to decode/decrypt the information that definitely is there— complex heterogeneous distributions over time in field strength, temperatures, convection patterns, etc.— into any form that isn't just repetition plus random noise.
I guess the issue is that you don't really know why you're conscious. If you had never seen a brain before, you would just think it was a useless blob of chaotically arranged fat. And even if you did know why you're conscious, you still wouldn't be able to say that that's the only way your specific form of consciousness can arise, nor that there aren't any other completely alien but equally conscious types of minds. Hell, homomorphic encryption means that it can be mathematically impossible to know whether any given complex system is just random noise, or contains someone's memories, experiences, desires, a soul. So given any system of adequate complexity, without knowing enough about it to put definite constraints on what it can do, I don't see how you could say for sure that it isn't "alive"/sentient.
When I hit my early teens, the example I thought of was n-body gravitational perturbations in something like the asteroid belt, and something like crystal grain structures in regular solid matter.
…Sucks for the lack of opposable thumbs, I guess, if it is alive. The information which may or may not be encoded in the sun may have unknown complexity and meaning, but I feel much more confident in saying that the amount of precision carried out by the solar wind and solar radiation will never allow it to shape and navigate the world around it like we can ours.
I think you are confusing statistically improbable, but completely normal, patterns with meaningful ones, which is probably the primary flaw of the human brain.
That said, it's also improbable that our meat brains can comprehend every possible form of life in the universe.
https://ui.adsabs.harvard.edu/abs/2007APS..4CF.E1013P/abstra...
Life deep within a sun-engulfed planet could perhaps survive for a while.
* https://www.youtube.com/watch?v=LhfCietvDZo