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New theory claims to unite Einstein's gravity with quantum mechanics
- sheepscreek 3y agoDid anyone else find the AI generated "art" more distracting than helpful?
- hn_throwaway_99 3y ago> A second paper, published simultaneously in Nature Communications and led by Professor Oppenheim's former Ph.D. students, looks at some of the consequences of the theory, and proposes an experiment to test it: to measure a mass very precisely to see if its weight appears to fluctuate over time. Definitely don't know enough to comment about the overall proposal, but given how many grand physics theories over the past couple decades have been untestable, it's really nice to see the proponents proposing a test.
- dotnet00 3y agoYeah, since untestable proposals for this kind of theory are basically the norm, the fact that they have a proposed test made me think it was worth sharing.
- Animats 3y agoIt's good that it's testable. This is one of those ideas which either wins a Nobel Prize or is totally bogus. So what does it take to test it?
- stjohnswarts 3y agoBogus usually implies something meant as a fake or counterfeit, I think a better way to describe it would be "incorrect", I don't think these scientists are trying to fake anything.
- szundi 3y agoUntestable theories are not theories - I mean, for what purpose and why care?
- colordrops 3y agoPath finding
- dotnet00 3y agoThe other big theories aren't completely untestable, the issue is basically that the models have a lot of parameters which can often be tuned in a way that leaves a possibility for the general theory to still work, and testing them to the point that any corrections seem too unreasonable is even more difficult and expensive.
- dragoncrab 3y agoNot reflecting to this particular theory, but in general history is full of theories which were not testable at their birth, but both engineering and the evolution of the theory eventually found a way to do so, even if it took a century. Black holes, Higgs bozon and neutrinos are a few popular examples.
- mr_mitm 3y agoSome theories are only untestable for practical reasons, like needing a particle accelerator the size of the solar system. That doesn't make them unscientific or "not theories". That is not the kind of falsifiability that Karl Popper had in mind.
- leptons 3y agoYes, it does. The word "theory" has a specific meaning. What this article is about is really a hypothesis, not a theory. I saw no evidence or data to back up what they think might be happening, thus not a theory. "In scientific reasoning, a hypothesis is constructed before any applicable research has been done. A theory, on the other hand, is supported by evidence: it's a principle formed as an attempt to explain things that have already been substantiated by data." Most people in this thread, as well as the writers of the article seem to be confused about the meaning of the word theory.
- guenthert 3y ago> it's really nice to see the proponents proposing a test. Is it feasible though? I wonder whether that test is not just outside of what can be technically realized today, but Heisenberg's uncertainty principle gets in the way.
- mikro2nd 3y agoWell,... measuring gravity waves was outside of the technically realisable for a long time, but a couple of decades of trial and refinement and it got realised.
- nojvek 3y agoLove that there is a test. Some of the theories like gravity waves and Higgs boson took almost half a century to be confirmed by experimentation. The hard part about this is building tools that can precisely measure mass fluctuations with extremely low error bars at picosecond timescales. Because we need to both validate the theory and that the device is correctly measuring. So much of science became only possible because of better instruments. Be it microscopes to see the tiniest phenomena or telescopes to observe the furthest phenomena.
- edgefield 3y agoI’m not a physicist much less an astrophysicist and so take what I’m about to say with a hefty grain of salt. But I wonder if this new approach can also explain observations of distant galaxies. Distant galaxies either redshift because they’re moving away faster over time due to dark energy or redshift because their mass is changing. Can this new theory help explain why older galaxies might lose increasing mass over time?
- thfuran 3y ago>redshift because their mass is changing. Why would that cause red shift?
- tycho-newman 3y agoLosing energy shifts the frequency of your emissions towards red. Basically, cooling down is the same thing as moving farther away from an inertial reference point.
- mr_mitm 3y agoAre you thinking of thermal radiation? And what does losing mass have to do with cooling down? We observe redshift in the spectrum. Hydrogen emits radiation in very specific frequencies, which are redshifted. This cannot be explained by losing mass, heat or energy.
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- rhelz 3y agoThe various standard kilograms held by the national bodies, and the prototype standard kilogram in paris, were measured very precisely over the past hundred years, and their weights did seem to diverge mysteriously.
- dataflow 3y agoWhat made them mysterious? Aren't there always some fraction of atoms or molecules with sufficiently high energy to escape the object?
- mvdtnz 3y agoThe fact that you, a random internet guy, knows this makes me believe that the world's top experts on measuring this exact thing probably thought of it, and if there is a mysterious divergence this probably doesn't account for it.
- dataflow 3y agoI figure as much, but that's kinda why I'm asking what made it mysterious. I actually hadn't heard of it being seen as mysterious until today - that comment is the first time I've seen that. Until today I thought it had been was unsurprising for scientists.
- yetihehe 3y ago> I figure as much, but that's kinda why I'm asking what made it mysterious. You expect simple explanations to VERY complex problems from random internet commenters. I think you expect too much.
- quickthrower2 3y agoNot on HN sometimes some gems of comments are made by experts
- lostdog 3y agoIs there a decent explanation of what the conflict is about, that is understandable with a non-physics-major college level maths background?
- whatshisface 3y agoGravitons don't work as force carriers in quantum field theory because the sums describing them diverge even worse than other sums describing the three other forces; sums which also diverge but can be corrected.
- mvdtnz 3y agoDepends how much time you want to spend on it. I first learned about this topic in Brian Green's book The Elegant Universe back in 2005 or so. At the time there was a glut of popular science books on the topic (Lee Smolin had an excellent book titled The Trouble with Physics which made an excellent counter argument to Green's string theory-heavy title). If you want to go much deeper, Roger Penrose wrote The Road to Reality which is a much much harder read (I was never able to complete it after 3 separate attempts).
- selecsosi 3y agoBeing _hyper_ reductionist, the standard model of physics, which describes, to an extremely high degree, the interaction (creation, elimination, and chance of one thing turning into another) of particles that constitute "stuff" (matter / energy) does not account for the interaction of matter via gravitation. Most things interact with each other, they create "particles" to exchange force / energy (actually in the case here much of this is actually virtual particle interaction / creation). An example of this is when two magnets are interacting with each other, the repulsion/attraction that the magnets / and magnetic fields, the force carriers there actually described by best by "virtual photons" https://en.wikipedia.org/wiki/Virtual_photon#:~:text=Virtual%20photons%20are%20thought%20of,other%20by%20exchanging%20virtual%20photons https://en.wikipedia.org/wiki/Virtual_photon#:~:text=Virtual.... The whole standard model is like this (protons/neutrons exchange gluons via the strong nuclear force). For gravity, there isn't a good "particle" we've found that can accurately describe how gravity behave. It's good to note here a "particle" is what is used to "quantize" something, and so quantum mechanics is the study of how these subatomic particles interact and are created when things like protons are smashed together in a particle accelerator. Gravity, on the other hand, behaves more like a classical theory (in the sense that it is a field, rather than a discrete quantized energy exchange). In the parlance of the field, mass, appears to cause a curvature in space time according to the rules (quite accurately predicted) in general relativity. This appears to be some sort of more reconciliation by acknowledgment of the different aspects of the behaviors of the models (GR vs QM), and chooses a path to verify this by looking at the breakdown of matter (in this case, entangled quantum particles) in a asomtomic limit that might be imposed on a quantized theory when that is subatomically reconciled against a continuous field like gravity. (My own notes) This might be indicating that there is a continuous nature (or at least continuous at the scales that these subatomic particles experience) such that when the particles interact with the continuous field, their movement creates some snapback of the field (thinking how movement in water creates microscopic cavitation) which disrupts what would be a continuous laminar flow in the water case, creating macroscopic turbulence (in this case disturbing the entangled particles) * Edit: a little clarity / notes on the SM/QM/GR overlap
- inasio 3y agoI was really hoping to find concrete details of what the experiment that they proposed to validate or refute their theory is. I hope it's something achievable, or at least not ridiculously far from what we can currently measure
- defrost 3y agoJonathan Oppenheim: If you'd like to attend a public lecture (virtual or in London) about the postquantum theory of classical gravity, or contribute a donation to the group's research program, click "Donate" to add your email address to our list. https://www.ucl.ac.uk/oppenheim/ https://www.ucl.ac.uk/oppenheim/ https://www.ucl.ac.uk/oppenheim/research.html https://www.ucl.ac.uk/oppenheim/research.html See Also: Gravitationally induced decoherence vs space-time diffusion: testing the quantum nature of gravity (March 2022) https://arxiv.org/pdf/2203.01982.pdf https://arxiv.org/pdf/2203.01982.pdf Is it time to rethink quantum gravity? (March 2023) https://arxiv.org/pdf/2310.12221.pdf https://arxiv.org/pdf/2310.12221.pdf
- Certhas 3y agoThis is all surprisingly substantative. That said, there are many results that connect gravitational and thermodynamic phenomena. It would be good to understand how these look from the perspective of this theory. Edit: just started reading, so if this is explained somewhere would love to get a pointer.
- maaaaattttt 3y agoThis is a question I've been asking myself (probably due to a lack of understanding and knowledge) and this theory seems to hint at something similar: why do we assume spacetime to be homogenous in its nature? Here they seem to say that on some quantum level spacetime could vary drastically. Couldn't then dark matter be explained by some variations on a large scale? Like giant "wrinkles" in spacetime? They would then behave as pseudo black holes, or more like "black trenches", that lead to the structures we see today in the universe. The structures seem to have more mass than what we can actually see, but are in fact just placed in locations that behave differently gravity wise?
- samus 3y agoScience had fared quite well so far with the assumption that the laws of physics are largely the same no matter where and when we are. There would have to be very strong evidence to throw that out. And the immediate next problem is that it actually wouldn't explain much. The immediate next question would be "why is spacetime behaving this way".
- maaaaattttt 3y agoUltimately it's just a way to say, "well, there is simply more gravity there". I was also thinking of the "why" and I'd say because when the universe expends, or initially expended, it didn't happen homogeneously. In my opinion it's more realistic that spacetime isn't homogeneous than that it is.
- psc 3y agoI've had the same question and I don't have the answer, but what you're asking about might be referred to as the cosmological principle https://en.wikipedia.org/wiki/Cosmological_principle https://en.wikipedia.org/wiki/Cosmological_principle Seems like so far our observations are that the universe is pretty homogeneous. Cosmological principle being the default position, my best understanding is that it's just a lack of evidence otherwise: > The End of Greatness is an observational scale discovered at roughly 100 Mpc (roughly 300 million light-years) where the lumpiness seen in the large-scale structure of the universe is homogenized and isotropized in accordance with the Cosmological Principle. At this scale, no pseudo-random fractalness is apparent. https://en.wikipedia.org/wiki/Observable_universe#End_of_Greatness https://en.wikipedia.org/wiki/Observable_universe#End_of_Gre...
- I_am_tiberius 3y agoSo in summary, if right, it means that spacetime is not as predictable as we thought.
- quickthrower2 3y agoAlmost as if it is a machine learning simulation :-)
- yathaid 3y agoThe article mentions the 5000:1 odds bet, but reading the text of the bet itself is hilarious: >>> Whereas Carlo Rovelli and Geoff Penington firmly believe that gravity is better described by a quantum theory. >>> And whereas Jonathan Oppenheim is more sympathetic to other possibilities (i.e. doesn’t have a clue) ... [1] - https://www.ucl.ac.uk/oppenheim/pub/quantum_vs_classical_bet.pdf https://www.ucl.ac.uk/oppenheim/pub/quantum_vs_classical_bet...
- bilekas 3y ago> a small amount of olive oil, balsamic vinegar, or wine I think we can guess who write up the contract!
- DrBazza 3y agoCrisps though! > Should space-time be shown to be quantum, the loser will give to each of the winners, one ITEM* of their choice. If the alternative hypothesis is deemed to be correct, the losers will each give 5,000 ITEMS to the winner. > * ITEM is defined to be a object of the winner’s choice, worth no more than 20 British pence on January 21st, 2021. Examples include some crisps, a bazinga ball, a small amount of olive oil, balsamic vinegar, or wine
- denton-scratch 3y agoThe contract doesn't specify what kind of balsamic vinegar. Supermarket balsamic is just a mixture of colourings and flavourings. Proper solera balsamic is sipped as an aperitif, and is much too expensive for me to have ever tasted.
- GuB-42 3y agoIt doesn't say the amount either, just that each item must be worth less than 20 british pence. So it can be one drop of "Aceto Balsamico Tradizionale di Modena DOP", which is the real deal. Prices start at around 50€ for 100mL, but it can easily go into the 100s if you want the more premium ones (25 years). A single drop would fit the 20 pence bill.
- hoseja 3y agoWhat awful AI-generated illustrations. Anyway, is there any justification for treating spacetime as a smooth manifold, except for mathematical tractability?
- staunton 3y agoYes. GR does it and GR gives good descriptions for a lot of observed phenomena.
- hoseja 3y agoExcept, you know, all the elementary particles. I have this intrusive thought those are just bits of non-smoothly kinked/knotted spacetime but have neither the physics background or sense where to even start to look further into that.
- fsckboy 3y ago>> Yes. GR does it and GR gives good descriptions for a lot of observed phenomena. >Except, you know, all the elementary particles. except, you know, all the elementary particles don't do a good job of explaining what GR explains
- TheOtherHobbes 3y agoHardly an expert, but it seems more likely to me that GR is the smoothed-out limit of a lot of much smaller stuff happening, than QM is somehow low-level wrinkles in an otherwise perfectly smooth spacetime. I don't think a smooth anything is physically tractable. You need infinite resolution for perfect smoothness - essentially an infinite amount of information at every point. Except there are no points. So somehow you have equations that define curvature floating in some kind of metaphysical space which somehow gets mapped to observable phenomena. And if it's a noisy smoothness - where does the noise come from?
- showlife 3y agoMaybe what you're looking for is a "geon"? https://en.wikipedia.org/wiki/Geon_(physics) https://en.wikipedia.org/wiki/Geon_(physics)
- 8bitsrule 3y agoA wonderful, bold, and colorful idea, already thought through carefully. And 5000:1 odds! It'll be more interesting how many more dozens of minds will find more testable consequences. Is it too much to hope that some untestable ideas will deservedly die?
- hallway_monitor 3y agoThat which can be destroyed by the truth should be.
- jeisc 3y agoOur present day understanding of the universe is rudimentary at best and will be rocked with each new device invented to reveal its nature to us. When we explode a nuclear bomb here how far away in the universe would it be visible or detectable? If there were a highly developed civilization would they not be listening for this background noise to detect when a civilization had reached the nuclear point and used it for exploding a bomb?
- tsimionescu 3y agoNuclear explosions on Earth, while very powerful, are not even a blip compared to the random noise in the amount of energy that the Sun gives out. You would have to very very carefully measure the Earth itself in particular to notice them in any way.
- bawolff 3y ago> and this scale can be determined by another experiment where we test how long we can put a heavy atom in superposition of being in two different locations." Im a physics noob, but does this imply the theory helps explain why we usually only see quantum effects on the mucroscopic scale, since it says something about how heavy objects cant be put in superposition?
- codethief 3y agoYes, at least that's my understanding.
- bheadmaster 3y agoI'm a physics noob too, but from what I understand, the quantum effects don't happen on macroscopic scale because of high temperature and lack of "structure". Every interaction of particles seems to change the state ("collapse the wave function") of the particles, so such a chaotic environment makes things start behaving in a predictable way. Sort of how balls falling in a Galton board seem to converge to Gauss normal distribution: https://en.wikipedia.org/wiki/Galton_board https://en.wikipedia.org/wiki/Galton_board In low enough temperature and regular enough structure, even macroscopic objects can be entangled (or, I assume, show other quantum effects): https://www.scientificamerican.com/article/scientists-supersize-quantum-effects-with-entangled-drum-duet1/ https://www.scientificamerican.com/article/scientists-supers...
- deleted 3y ago[deleted]
- jug 3y agoHonestly at this point, who knows. Let's find out. This is even a testable theory so that already puts it ahead of a host of others.
- netfortius 3y agoI am a huge fan of Carlo Rovelli, and read all his books to date, so I am siding with him on this one.
- eterevsky 3y agoPrevious discussion on HN: https://news.ycombinator.com/item?id=36667278 https://news.ycombinator.com/item?id=36667278
- amai 3y agoSee also https://www.quantamagazine.org/the-physicist-who-bets-that-gravity-cant-be-quantized-20230710/ https://www.quantamagazine.org/the-physicist-who-bets-that-g...
- maho 3y agoAfter skimming the second paper, I still don't understand how precision mass measurements come into play here. They mention Cavendish-type measurements, but they are used for measuring the gravitational constant. Of course, you can turn the formula around, plug an unknown mass into the apparatus and then call it a mass measurement, but it's going to be a very imprecise measurement. A Penning trap can give you 11 to 12 significant digits -- a Canvendish-type measurement could give you maybe 5 or so, I think. Or is it because the Penning trap measures "inertial mass" but they really want a measurement of "gravitational mass"? But wouldn't inertial mass fluctuate the same way?
- Timeroot 3y ago(I went to a talk by Oppenheim author a couple weeks ago on this topic.) The idea is that gravity, as a force, only operates classically. More precisely: there is a classical state describing the curvature of space time, and then a quantum state describing the configuration of particles on that spacetime. But then, that quantum state needs to affect the classical state again (mass bends space), which would usually lead to the classical half becoming quantum and entangled with the other half. You can keep the classical half (the shape of spacetime) classical, if the effect of the quantum part is partially stochastic. There's a minimum amount of random noise you need for it to be mathematically consistent. So, you set up an experiment where a particle is acting on another via gravity. There's a quantity of noise you should expect to see in the gravitational force. "Inertial Mass=Gravitational Mass" now only holds on average. The gravitational mass will effectively have a Brownian noise term added in.
- Workaccount2 3y agoSo if I am understanding this correctly: Quantum particles can effect change (curve) spacetime without direct quantum action if you sprinkle a bit of randomness into the (quantum acting on spacetime) effect?
- a_cardboard_box 3y agoIf this hypothesis is true, would it give us a way to distinguish many-worlds vs. wave function collapse? If the many "worlds" are all interacting with a single classical spacetime, we should be able to measure the gravity of other worlds, right? I'm not a physicist, but that sounds a lot like dark matter to me.
- kristov 3y agoI wonder: does this theory explain any currently unexplained phenomenon? It may be testable, but that doesn't guarantee it to be correct. There could be another undescovered theory that also passes these tests. It feels weird to make up a theory, and then make up some tests to validate it, without mentioning the actual problem the theory is trying to resolve. It seems physicists just don't like there being two separate models, one for large things and one for small things, but it could be the universe is just like that, right?
- naijaboiler 3y agoTheories like that are never “correct”. They just explain things and fit data better than other/previous theories. Correct is not what I would go for. “Best we currently have” sounds more like it
- mettamage 3y agoDisclaimer: not a physicist. It seems to me that one issue with falsification is that: if you're exactly right on how the universe works, then it's hard to know that you are exactly right. So I imagine that we'd be infinitely putting resources in it (to some extent) to see if anything is unexplained. So if the universe is just like that, then we'd have a long way to go to find out. I do think that physicists are bothered by the idea that current theories can't explain everything they're observing. So whether the universe is or isn't like that, more research is definitely needed.
- simiones 3y ago> It seems physicists just don't like there being two separate models, one for large things and one for small things, but it could be the universe is just like that, right? No, it couldn't be just like that. There could exist a common umbrella theory that uses GR for certain objects and QM for others, but it would have to be a new theory that introduces a very important new info: the nature of the separation between the two. Right now, all of the laws of QM say that it applies just as much to the motion of the Sun as to the motion of an electron. GR says the same. And yet, GR's predictions for how an electron behaves are clearly wrong. QM's predictions for how the Sun moves are closer to being correct (that is, QM + SR + Newtonian gravity), but it is hard to measure. A unified theory has to either correct the equations of QM, GR, or both; or to add explicit boundaries to each of them. A theory that would say "an object moves according to the laws of QM if it's 0.00000001g or lower, and according to the laws of GR if it's any higher" (or any other distinguishing characteristic) would be an entirely new theory. Interestingly, this new theory being proposed in the articles actually does something slightly in this vein: it says "QM applies to the electromagnetic, weak, and strong interactions, and GR applies to the mass/gravity interaction". It then finds a new way to account for the known inconsistencies between the math of each, apparently by getting rid of the assumption that a particle has a fixed mass (and thus fixed space-time curvature in GR).
- FrustratedMonky 3y agoAny physicist here that can tell if this is the big breakthrough to a theory of everything? Or just hype? Sorry, gun shy about believing big breakthroughs this year. Quantum Gravity and Testable? Seems huge on the surface. If it can be tested, then this is already worlds ahead of string theory.
- throwaway4PP 3y agoExciting times! Any physicist here aware of how these two papers would impact the applicability or validity of Modified Newtonian Dynamics (MOND)? background: my lay understanding of MOND is that it modifies the gravitational interaction parameter over cosmological distances. the force exerted on objects due to gravity is currently accepted to scale with distance in a certain manner (ex. 1/distance^2) while MOND postulates a different scaling relation (ex. 1/distance^3). Those are just examples, not actual values. The currently accepted gravitational interaction force scaling is what gives rise for the need for dark matter, and the corresponding lambda cold dark matter (LCDM) theory. Of course, we have not been able to observe dark matter, which is a problem for a theory. That is what has given rise to MOND, amongst other things. There are prominent, esteemed physicists who have recognized many issues with LCDM, some of which are addressed by MOND (https://astro.uni-bonn.de/~pavel/kroupa_SciLogs.html https://astro.uni-bonn.de/~pavel/kroupa_SciLogs.html) previous HN posts with interesting discussions / links re: MOND https://news.ycombinator.com/item?id=37012052 https://news.ycombinator.com/item?id=37012052 https://news.ycombinator.com/item?id=33261981 https://news.ycombinator.com/item?id=33261981 https://news.ycombinator.com/item?id=23982814 https://news.ycombinator.com/item?id=23982814
- Timeroot 3y agoIt's of no relevance to MOND, at least none that I can see. MOND gives a different scaling relation, and is therefore contradicting general relativity. Its goal is to explain the effects we associate with dark matter, without the need for dark matter. General relativity is (we are pretty sure) inconsistent with quantum field theory. String theory tries to fix the issue by replacing the particles in field theory with strings. Oppenheim is trying to fix it by putting general relativity as a classical phenomenon that lives "outside" of quantum field theory. They're trying to solve different problems. And, Oppenheim's classical gravity picture could be used just as well with MOND instead of standard general relativity, if that's what you wanted. MOND is getting less popular every year as evidence for dark matter piles up. The Bullet Cluster is a particular instance where we can actually "see" the dark matter flying around, in a way MOND couldn't hope to explain. LIGO has also given us a lot of confidence we have the right theory of gravity, at least up to the quantum scale.
- curation 3y agoWhat if universality is a name for a kind of antagonism? What comes first is not a wholeness that is disturbed, but difference itself. Reality itself is unfinished and built in parallax. This new theory alongside current metaphysical theories of everything is inspiring.
- VHRanger 3y agoWhy is this comment at the top of the discussion thread? We're talking about the validity of the mathematical theory, not new age woo-woo methaphysical theories.
- stjohnswarts 3y agoSo can anyone explain why this will possibly take 20 years to prove/disprove? We don't have the current level of accuracy necessary to test it, but might if we work through issues over the next 20 years or so?
- qwertywert_ 3y agoSo to unify the theories they are actually keeping them separate?
- codethief 3y agoIn a way, yes, but not exactly. As far as I understand the idea is that gravity induces the collapse in quantum mechanics, which would be a huge conceptual change (and IMO a very satisfying solution to the measurement problem). Moreover, according to the article this collapse does not preserve the key property of quantum mechanical time evolution: unitarity (aka "preservation of past information" aka "predictability of the future"). > The new theory allows for information to be destroyed, due to a fundamental breakdown in predictability.
- zehaeva 3y agoHoly hell, talk about burying the lede here! The last sentence of the whole article is: The new theory allows for information to be destroyed, due to a fundamental breakdown in predictability. Are you kidding me?!
- nine_k 3y agoIs there something fundamental that breaks when information is allowed to be destroyed?
- zehaeva 3y agoI mean, yes, things like The Arrow of Time, Entropy, our entire understanding of black holes, most of quantum mechanics. Yeah, if information can be destroyed then a lot of physics needs to be redone.
- mackman 3y agoWouldn't that prevent time from going in reverse?
- nine_k 3y agoIsn't the growth of entropy preventing this already at the macro scale? Isn't it similar to the loss of information, because it's a transition from a less-probable state to a more-probable state?
- digging 3y agoI mean essentially, quantum physics only works if information can't be destroyed.
- deleted 3y ago[deleted]
- amai 3y agoI believe gravity can be both quantizable and non quantizable. Gravitons could be like phonons (quantized sound waves) and only exist in the solid state of space time. In the fluid state of space time gravitons don’t exist ( Similar to the fact that phonons can only exist in solids, but not in fluids).
- digging 3y agoWhat are the solid and fluid states of spacetime?
- amai 3y agoOne could imagine that for a very low Unruh temperature spacetime changes the phase and becomes „solid“. A low Unruh temperature means very low acceleration/gravitation. This might explain dark matter. Similar things are discussed in the literature under https://en.wikipedia.org/wiki/Superfluid_vacuum_theory https://en.wikipedia.org/wiki/Superfluid_vacuum_theory and https://penntoday.upenn.edu/news/physicist-theorizes-dark-matter-superfluid https://penntoday.upenn.edu/news/physicist-theorizes-dark-ma...
- berniedurfee 3y agoWere the illustrations AI generated I wonder? They look very interesting and abstract, but still made to fit the narrative.