in order for particles to be made out of space-time, space-time would have to really exist as something separate and fundamental, like another quantum field. Is that accepted as fact? Or is space-time just what the pre-20th-century guys were calling the em-field before quantum fields were known?
I know some people will say it's too technical, while some say it's too dumbed down. I'm here to muddy the waters further and say you are presenting the information just right! Thank you for these well thought out presentations of dense material.
Don’t shy away from the maths! It’s intimidating at first, but the more you are exposed to it you start to see if as just another language that you do not understand fully.
It's not "just right", because many of these ideas are not forgotten, only the ones that are wrong. The Einsteinian antisymmetric metric tensor re-emerges in string theory, and also, the "particles are black holes" idea is realized, except in a quantum context. Einstein's ideas could not be right because they are classical, and he should have known better even back then.
I agree, when one is at the forefront of new things, tis inevitable that there will be omissions, errors, misunderstandings or even simply ignorance (whether it be accidental or willful) in any materiels produced in any new fields. It's the Scientific Method to test to confirm new ideas. If successful those Ideas stays, if an idea fails, it's up to the scientists to figure out why and either modify as needed or ditch ideas altogether (at least until new data surfaces to warrant revisiting a prior failed idea that may then work with new understanding of the latter times. The body of Scientific Knowledge is built upon the foundation of fundamentals that adds up to Laws of Physics and Quantum that ultimately leads to the final Unified Theory of Everything. Obviously we do not have all or at least enough of the Fundamentals down pat …yet. Eventually, with perseverance and due diligence, we will learn more and we will get there.
I love when you present little hidden gems like this. I'd never run across this idea and physics history otherwise. Perfect level of technical explanation, as usual too.
That idea that spacetime curled up onto itself is what makes particles is explored in a set of papers by Dr. Howard Perko. He has derived the equations from an idea that spacetime can be represented as hyper surface tension. So it’s not just a membrane, it can also have fluid dynamic properties as well and GR comes out if shear is set to zero. I think he is on the right track and I sincerely hope that you at least take a good look at his papers.
Read my recent Medium article, and feel free to provide feedback. Ties in with your comment. "Grasping Vital Points Most Physicists Misinterpret About Reality"
Curled spacetime on itself like fluid mechanics where particles emerge? It sounds like the infamous "ether". So interesting, I'm going to take a look on this idea
@@SabineHossenfelder Hello Is it possible you could do a video on Einstein's original other unified field theory? I've never heard of this alternative theory till now will but it's actually right!! It fits into my Super Unified Field Theory or (SUFT) it fits even better than the one that he's known for but I would like to make sure. I am attempting to have it get peer-reviewed and I require feedback on it but so far no one wants to have anything to do with it for whatever reason!! The Reason No One Has Been Able to Come up with a Proper Unified Field Theory, You Need to Quantize Time First!!!! It's The Key To It All Without It You Are Wasting Your Time Trying!!! I did send you a copy of my SUFT formula to your website e-mail hoping you might take a look at it!! There are nine different studies that all have predictions in SUFT for them and it explains their results better and more accurately!!. I will send you a new e-mail with the studies and the SUFT formula and hopefully you will find it all very interesting.. Thank You John
It's great to see ANYBODY talking about this finally. But I must point out a very much missing historical point - Weyl got the unification ball rolling in 1918 with an extension of Riemannian geometry in which the length scale was localized as a field. This brings in the A_mu as the "gauge field", which is where the term originated. Weyl's idea doesn't work in 4D because there are no irreducible Lagrange densities that are both coordinate scalars and gauge invariant. However it DOES work in 6D and allows a complete, irreducible solution to the problem. Einstein was right, again. (Look for "Gravitation and Electrodynamics over SO(3,3)" if your are interested. It works in principle for any gauge group, but the calculations have only been done for U(1), which was hard enough by itself.) BTW Pauli showed the KK theory was itself reducible in that any generally covariant theory can be patched onto GR this way. The gravitational and electromagnetic potentials are physically different things after all.
I'm trying to get some work done for a project of mine and I need interesting videos playing and couldn't find any until finally you popped up! I dread what it'll be like 13 minutes from now...
This is one aspect of the Wolfram physics project. That maybe particles are not elementary but rather an emergent thing in spacetime. Their spacetime is actually space, on the form of a graph, and time, in the form of rewrites of the graph. So it's not fundamentally equations, instead is an operational deception on how space and time actually works. And particles could then be some kind of "knots" in the graph, analogous to how a knot on a rope is an emergent phenomenon of the rope itself. You can move the knot on the rope but it's still only rope... I find this exciting as this is an entirely different paradigm to try to tackle the problem of a theory of everything.
@@michaelwinter742 I'm mostly sure that is just a coincidence, but maybe not. Maybe the SU(3)xSU(2)xU(1) stops at 3 because of our number of dimensions, but that just seems like a random selection, or, like, asking why gravity is as strong as it is. For now, it just is. But maybe a ToE will show how space and the forces are all together, maybe it won't, only time will tell...
Fascinating, can we have more of these technical & detailed video's please. I appreciate they are not for everyone, almost certainly a minority, so maybe a sub-series. This video has enough material for a whole series explaining all the different theories and approaches. Thanks Sabine p.s. keep up the rants, physics needs them.
When you talk about Einstein & show equations, you get excited and talk faster... BUT ! When you talk about Einstein & actual equations, is when us normal humans need you to talk slower !😁
@@ylette I know what many of the letters mean, most of them, even, tho not formally, and it isn't particularly important to the discussion at hand. She points out and explains the parts that are relevant for the viewer, without overloading them with info. Granted, I always think more information is better than less information, so some quick text on the screen about the equations shouldn't hurt.
@@lanorothwolf2184 I think she thinks she gets paid more to add in the h that doesn't need to be there. She only says his name about 600 times a video.
@@ylette That's an entire video in itself. More likely multiple videos. And people would definitely get bogged down in the confusing concepts those variables imply, which would distract from this video's main points.
I don't know how ALGOL is your first example language as it is very obscure, but I do not see a version if ALGOL that uses C-style block comment syntax.
@@gamechannel1271 C style comment blocks were borrowed from ALGOL, which came first. I'm a C guy, but calling them C style comments isn't any more accurate than calling them Java style comments.
I'm glad you're keeping Einstein's ideas alive, Sabine. We need to learn from history, both the good and the bad. Btw the idea that matter is the same as space (i.e., "extension") goes back to Descartes. The analytical-geometrical branch of physics (such as GR; as opposed to the thermodynamics-QM branch) is all downstream of Descartes.
I think this is a fantastic video and topic. My appreciation to Sabine for this. As an undergrad engineering physics major, I read the book "Subtle is the Lord" by Abraham Pais and took the time to learn German specifically so I could read his book about Einstein's later papers. I studied Kaluze-Klein and the Einstien-Rosen papers specifically. I'm not smart enough to work at that level but do hope someone that is continuing with that line "particles and space-time warped in specific ways" idea. I think Sabine is right it is a line of thought that needs to be investigated more.
hypnotic. i nod my head, i smile, and at the end of the exposition i have learned that einstein spent half his life wandering through physics to no avail. there is a lesson in this: if you must study physics, do it in your spare time, but concentrate on cabinet-making or pottery. you have something to show for your time on earth.
A lot of philosophers would tell you the pots and cabinets will break and be thrown away and your work will soon be forgotten. Even Einstein will be forgotten one day. Don't seek meaning in what you leave behind.
I had been considering this theory myself and never knew Einstein thought of it before. It seems like an obvious next step from relativity to describe fundamental particles. I always liked it because it also describes what is happening when you try to move matter throu space. It's like pushing a canoe through water. It takes energy to separate the water at the bow, but you recover that energy when the water comes back together at the stern. Something moving at a constant speed doesn't require additional energy to keep moving. To accelerate, you have to put in energy to open the space in front of the object slightly faster than the energy is recovered at the back. When you try to push it faster, you get to a speed where the water behind can't come back fast enough, and a cavity is left behind the vessel. The faster you go, the longer this cavity is, requiring much more energy to accelerate. Effectively, it's mass grows. This seems to describe Newton's laws and Einsteins laws at once.
Wow, this is exactly what I'm currently researching! It's technically just vacuum GR, but I've found that it seems to explain a lot. I've already overcame the issue Einstein had at 3:01 . I'll send you an email about it. Regarding 5:35 , it could if you discard the cylindrical condition. Regarding 9:45 , Teleparallelism is an equivalent formalism to 1915's GR. Both give the same predictions for vacuum GR, the case where Ricci curvature, torsion, and nonmetricity are 0. Consequently, Kaluza-Klein theory can be reformulated in tetrad formalism with more than one compact space, which can be more complicated than a 1-sphere. I suspect that Teleparallelism's Kaluza-Klein variant is more mathematically elegant looking than 1915's GR's Kaluza-Klein. I can also share with you my reasoning why this can still give rise to quantum effects. It actually has to do with a Superdeterministic formalism of GR I've been working on.
I like these high level videos, it's more contextualized than just a history lesson and connects some dots that aren't obvious to people outside the field
11:12 I've asked scientists about this and gotten goose eggs on it. I've always wondered if matter was based on curved space rather than curved space on matter. I figured it was my craziness. Sabine, you rock!
I’ve been thinking about the theory where our universe might be inside a black hole. Here are the key points that I thought of (feel free to question everything): The general idea is that the regions of space, before and after the event horizon, have an opposite arrow of time. 1.External Perspective: From outside, our universe looks like a black hole with an expanding event horizon. As matter falls in, it appears to slow down and redshift, similar to objects approaching a black hole’s event horizon. 2.Internal Perspective: Inside the black hole, time appears to move forward normally for an observer. The universe expands, akin to a white hole, with matter and energy moving outward. 3.Symmetry: There’s a symmetry between the perspectives. Outside observers see our universe as a black hole. Inside a black hole, the expanding region looks like our observable universe. 4.Entropy: From the inside, the universe’s expansion increases entropy, consistent with the second law of thermodynamics. This aligns with how we see our universe’s entropy increasing. 5.Evidence: To test this, we could look for subtle signs in the cosmic microwave background or gravitational waves that might indicate a central singularity or different entropy dynamics.
When I first heard of how gravity works according to General relativity, I had the thought that what we observe as matter is propably just space curvature. And that there's no matter needed that curves space, but it's space curvature itself that creates the illusion of matter. I was also sure that someone else must have had this thought before me. Hearing now that it was Einstein himself who thought of it this way, makes me a bit proud of my self 😊 Thanks for this video, Sabine!
I enjoy this format where you talk about ideas from the past, who had them, who else build upon them, in a quasi-chronological order. I find it very interesting to learn about how science evolved as well as how old some of the ideas are. If you decide to make more of these for other topics, I'm in!
I was wondering about that a few years back, did some back of the envelop calculations and it turns out it's at leas theoretically possible and when you reason from first principles it's even likely that particles are black holes. What is more important is the fact that a black hole IS in essence a single particle/object. Whatever it causes, classical particles cause it too just with lower magnitude - think frame dragging. Protons, electrons etc. also have a frame dragging effect, just a lot smaller - think along the line of spin.
Wonderful video, Sabine. Thank you very much for taking the time to expound upon something that, as a lay-person who cannot read German, I have wondered about for decades.
I'm speaking as an educator when I say this: It is a shame that we don't teach students in primary school (or secondary school) much of anything about the history of science (or mathematics). It has been my position for some time now they we should reintroduce curriculum for the instruction on the history of science and mathematics, because I have become convinced that, not only was it a mistake to remove these subjects in the first place, but also we can begin to overcome the fundamental road blocks we run into again and again with so many students when it comes to math and science. We now have a generation of educators who also did not learn or study the history of math and science disciplines. When I first decided to independently study the material for a college level history of mathematics course, almost immediately I found myself wondering why this class isn't taught in primary school, or at the very least made a prerequisite for most (if not all) undergraduate college degrees. I also found myself lamenting the fact that I had been deprived of what I would could consider an essential foundation of general education. I'm bringing this up because the video is about history of the development of Einstein's lesser known ideas, which it would be expected that only specialists would be aware of, for the most part, because usually only students who are studying the relevant, narrowly focused subject matter are though to have need of the benefit of exposure to the historical context in which the key ideas in their field or discipline developed. It is extremely useful, and greatly aids in students' understanding and retention, I believe, when we pair the fundamental concepts with exposure to the contemporary history when this ideas, concepts, and theories were being formulated. If nothing else, I strongly believe this will be of great benefit, even if only because a layer of abstraction in how we teach math a science will be removed and replaced with something entirely concrete, because no one actually learn BETTER when things are presented to them as pure abstractions as opposed to something concrete. Education shouldn't be merely about preparing current and future generations to become good little workers, as if our only purpose is to become one of but many useful and productive, but ultimately insignificant, and eminently replaceable parts in our self-perpetuating, self-justifying system. The point, or goal of education, is to teach new (and sometimes old) people how to become competent, and most importantly, confident that they will be able to understand and navigate the larger world, and have to tools to handle NOVEL situations that will INEVITABLY arise in the myriad so-called "real life" situations.
Geometry. If you take something that follows the inverse square law (e.g. light from a light bulb) and constrain it to only travel in one dimension (e.g. by putting the bulb in a flashlight), its intensity will drop off fairly linearly instead of exponentially.
If you assume Gauss's law, that implies an inverse square law. The math is approachable, like Calc III level, it's a good exercise to show that yourself.
To add on to others comments, imagine the strength of the force spreading out in all directions. If the strength only depends on distance, all the points that feel the same strength will be the same distance away. Now, all the points that are the same distance from some single given point form a sphere (in 3 spacial dimensions), and so the force needs to cover the whole area of the sphere. As the distance increases, the area of the sphere increases (as r^2), and so the strength of the force needs to spread out more to cover the whole area. So if it only depends on distance, and gets weaker the further you get, the only real option is for it to scale as 1/r^2. Notice this works for both EM force and gravity. It doesn't for the two nuclear forces as the weak force doesn't scale with solely distance like that (at least within its range), and the strong force increases in strength as the distance increases.
Yes. It's because both gravity and EM are long-range forces (compared to the nuclear forces), i.e. they can be observed at macroscopic distances. Thus, at a distance r from a mass or a charge, their gravitational or electric flux is diluted over the surface of the 3-dimensional ball surrounding the mass/charge. That surface is a 2-dimensional sphere with area 4 pi r^2. The force is proportional to the flux (area-)density, i.e. the flux divided by that area, which is why you get an r^2 in the denominator in both cases. So in summary, both forces are long ranged and we live in three spatial dimensions, that's why.
Thank you Sabine. I have been interested in the black hole electron theory and the kaluza-klein theory for some time now, and I appreciate your coverage of Einstein's original unified field theory. I had not heard about it in this manner before. Have you heard about the Wolfram physics project? I think it could make an interesting video, and it has some interesting connections to Einstein's unified field theory.
Einstein's relativity was so dammed elegant that he couldn't believe the quantum world was any less elegant. But I'm no Einstein..or Hossenfelder for that matter, great videos thank you
QFT is very elegant. That was never Einstein's complaint. His complaint was primarily about the probabilistic nature of quantum mechanics, but that doesn't really impact it's elegance - just it's intuitiveness. There's a reason he couched his complaints in religious ideology ("God does not play dice") rather than any sort of elegance argument. He was smarter than that. > QM is going to turn out exactly as he would have been satisfied. Doubtful. There are good reasons to believe QM can not be built from any non-quantum theory. "Good reasons" are not proof of course, but they're also not nothing. > Not sure why some are trying to quantise gravity. Because there is no experimental or even theoretical basis for trying to go the other direction. There's only arguments based on "classical is more intuitive!", but intuition has tended to serve us pretty poorly under both QM and GR (hell intuition was already serving us kind of poorly under Maxwell's fully-classical rendition of EM).
@@lmff620 > what does that statement or that idea even mean? That's the kind of question we've just had to learn to live with when it comes to quantum mechanics. The only meaning we get out of it is often "the math matches experiments so yay". Trying to assign _meaning_ to what we find is something philosophy has been struggling with ever since we proved that quantum effects are real and unavoidable. We really, really want to have an human-scale intuition - a "meaning" - for quantum mechanics and there just isn't one.
@LisaBlooper > because you cannot fathom what it could (not just what it would) look like Correct. Specifically, I cannot fathom what it could look like that doesn't disagree with established experimental evidence. I'm not God to be sure. As I already stated, I can't _prove_ that it's impossible. But I do find it extremely doubtful. Some random person's "I think it could be this!" comment on the internet is not anywhere close to sufficient to erase or even reduce my doubt. > see Penrose for getting started. The difference is that Penrose does his homework. When he presents something, he has the math to back it up. Sure, he sometimes still pulls ideas out of thin air just because they "make sense" to him, but he also ensures that his ideas make sense within the context of known experimental evidence and existing well-tested theories. By comparison you're trying to push an idea that _Albert Einstein_ couldn't make work. That he couldn't make work with only electromagnetism, before we knew about the strong and weak forces. I'm willing to bet you haven't done your homework as Penrose would have. > incorrect In what way? Where is this theoretical basis you believe exists? Again "I think it might be!" is not a theoretical basis - that's just an opinion. Build a theory on that (or point me to one if somebody's already done it) and I'll be happy to admit I'm wrong. Serious theories only please - I'm not talking about a random Thunderf00t video or similar that's just as much wishful thinking as your own assertion. > not to mention I don't have a clue what anything in this paragraph means. That's a lot of words that don't seem to say anything. Doing what with my hands exactly...? > "a particle in 2 places at one time" I'm not sure if this is just more of the woo as it's in the same paragraph, but this particular type of phrasing is fairly common shorthand for describing uncertainty in lay terms. Obviously it's not correct, but perfect correctness is not the point when you're trying to describe complex topics in a simplified fashion. > there is something much more profoundly different with going in g>q direction than with going in q>g direction Which is both subjective, and 100% irrelevant. The universe gives exactly zero poops what you or I or anyone else believes is "more profound". It works how it works whether we like it or not. > think a little bit deeper about what the difference actually is No, because I don't care. What I care about is whether any theory matches experiment. Concepts like being "profound" or "intuitive" or "makes sense to me" do not really interest me in any way. What I want to see is the math. Ideally I'd like to see the experiments, though I'm aware that our experimental capabilities are not anywhere close to being able to probe the energies needed so for now I'd settle for "if we had unobtainable amounts of energy, here's the experiment we _could_ perform". Maybe with some simulations to show that the proposal is at least plausible despite not being able to test it directly yet. What I'm never going to be interested in is "I think this way is more profound!", especially when it contradicts the existing well-proven theories. But hey, at least you've (so far) only contradicted theory and not experiment - you're doing better than most.
@LisaBlooper haha I often wonder if this is a battle between GR and QM or between determinists and probabilists. (Which means they don't like the philosophical implications of the other theory) The score is 3 to 1 for QM though.
So theory of everything might postulate that elementary particles do not actually exist? So that any elementary particle can be broken down to some field curvature? 🎉
Wow ....does this mean intence gravity makes spacetime go round n round at boackhole horizon and eventually spaghettified spacetime breaks into small spacetime chunks or strings?
@@SabineHossenfelderSabinne i love your perspective and humor, however, i would also love if you injected some philosophy into it as well. For example. If you can marry physicalism and existence monism with field theory, you can get a theory of everything. I dont believe matter is emergent but thats because my definition of matter is simply that which is spatial, empirically verifiable and changes.
This was a clear explanation to all. but allowing those with some further understanding to see the maths and visualise the concepts. The discourse about what our intelligent friend was thinking later on is greatly appreciated.
Didn't realise Einstein followed through on this. I came to this conclusion myself too, wrote a book detailing how this makes sense back in 2022 actually. Funny, nice to see Einstein thought it was a good enough to dedicate the rest of his life to
I LOVE it when Sabine "rants"! 🤩 ! More ranting please! And more of these awesome general relativity/ black hole / Einstein videos... such a COOL topic,
Fascinating video! You were going so fast that it was hard to keep up. But there were several connections that caught my attention. I'll have to replay the video to refresh my memory of what they were. But one of the later ones in the video was the mention of spin 1/2 in relation to the Kaluza-Klein (KK) theory, which didn't work, as the KK didn't incorporate it, if I interpreted what you said correctly. But then you mentioned that KK (or presumably even higher dimensional variants of it) can work if supersymmetry is incorporated. It's been so long since I read various 1980's and 1990's books on supersymmetry and superstrings, that I either didn't know about that connection or had forgotten about it.
Here's an example sentence: "The spacetime tensor, denoted by gμν, describes the intricate fabric of space and time, encoding the gravitational field and curvature of the universe, and is a fundamental component in the quest for a simple unified theory that reconciles general relativity with quantum mechanics." And here's a simple paragraph on a unified theory: "A simple unified theory, often referred to as a 'theory of everything,' seeks to merge the principles of general relativity, which govern the large-scale universe, with the laws of quantum mechanics, which govern the behavior of subatomic particles. This theory would provide a consistent explanation for all phenomena in the universe, from the smallest particles to the vast expanse of cosmic structures. The development of a unified theory is an active area of research, with approaches such as string theory and loop quantum gravity offering promising avenues for unifying our understanding of the universe." - scratches head... huh.
This is how the term "theory of everything" is used today, but Einstein wasn't a big fan of quantum physics. He wanted to explain the quantization of matter (as with it having discrete units, particles) but he probably assumed that this entire quantum mechanics business would be replaced by something else sooner or later.
@@aaronjennings8385 That's funny. Does AI know that "promising" figuratively means "it will likely deliver", but it's literally correct also for "lying con-job", as in both cases, promises are made.
Nice video. For 5+ years I have been rambling about my stupid idea that matter and energy are simply made out of space. Good to know Einstein had the idea as well so it's not complete lunacy. Not sure why just about everyone seems to have forgotten about it. It explains so much when you start thinking of the consequences of it.
Many generations of physicists since Einstein have thought about this. Whether it is space-time knots or some other thing, it is not something that was forgotten. It just has never led to a better understanding. I don't know if it is wrong or right, but it is an idea that never entirely dies.
Back when I was in mathematical physics seminars in university, my pet idea was trying to look at field theories on lattices with a fundamental length scale. I still think it is a good idea, but as a middling mathematician and a middling physicist I was never able to get any of the ideas to work out. I always kind of hated QFT at the time, despite finding the math interesting, mostly because the combinatorial explosion when you increase the size of a system always made me uncomfortable. It always felt to me like the mathematics was trying to tell us this isn't the final answer. Like Ptolemaic epicycles on epicycles.
but the combinatorial explosion only happens when solving the equations using perturbation theory (also known as Feynman graphs in this context). It's not in the field equations themselves.
@@deinauge7894 Maybe my lack of familiarity (I only did pretty basic quantum chemistry stuff calculating electron wave functions with lumped nucleon models), but the way that symmetry and anti-symmetry are normally set up involves additional position variables for every additional electron, and constraints involving every permutation of the fermions. And my brief experience with second quantization didn't really seem any less complicated (quite the contrary in fact). It's possible I got a bad/incomplete impression, though. Like I said, I wouldn't say I was fantastic at it by any means.
Dirac again! That guy was fundamental too. Newton. Einstein. Feynman. .... Feels like Dirac should be here too, but all I've got is the fa 13:02 ct (okay. my perception) that he comes up all the time. I don't understand really. But he's always there when any teachers get down into the guts of physics. ... that's it. That's all I've got. 🤦♂️ I love this channel!❤👍👀
Dirac was probably the second greatest physicist of the 20th century. It’s a mystery to me why he (like James Clerk Maxwell before him) aren’t household names.
@@JonS because you need to be in grad school to appreciate why his equation is such a banger. And his lectures on QM, where decides the Poisson Bracket is a commutator with some imaginary non-zero value are...pretty abstract.
Sabine, if you haven't already seen it, you might be interested in Hadley's work, "The Logic of Quantum Mechanics Derived from Classical General Relativity". This would also dovetail with your research in superdetermisim. In later papers he also shows that spin 1/2 emerge if certain conditions are satisfied. I always found this research interesting.
If virtual particles were virtual micro black holes, it might explain spooky action at a distance using EPR=ER since they'd could be created in pairs and maintain entanglement. It's my view that this would be a neat explanation to the double slit experiment.
Thank you Sabine, I have greatly appreciated this video, very interesting and informative. And your channel is one of the few where one can listen to the correct pronounciation of “Schwarzschild” 😉
This was a wonderful exposition connecting so many interesting ideas and developments of the last 100 yrs. Whether a theory worked or not is one question. Whether a theory is a mathematical continuation or unification of something else is another. Very interesting set of thought experiments and mathematical models!!
Dear Sabine: thank you for posting this video and discussing Einstein's paper. I have unironically downloaded the paper and I am working on it right now to incorporate some of its ideas into my work.
Yes, they are both long-range forces which means the force (of a point mass) falls with the inverse or the surface of a sphere, that scales as R^2. This also tells you that in any other number of dimension the force law goes with a different power, and that in general it depends on the geometry of the space. (The strong and weak nuclear force are short-range interactions and do not follow this law.)
Is this not a good argument against extra dimensions (side glance at string theory), even very weenie tiny small ones? Or at the very least, an argument that gravity/electromagnetism only interact in our three spatial dimensions?
Hi Sabine! Love your videos and it's great that people like you talk about science to the general public including laymen like me. I signed up to Brilliant thanks to you 😄. I'm slowing making my way to your quantum mechanics' course. I am curious though, whether quantum field theory has any relationship to this topic? Say for example, the specific wave packet in an electron field is what curves spacetime? Or it's interaction with the Higgs field is what curves spacetime? From my perspective, there's certainly similarities between matter arising from spacetime, and the vibrations in fields which permeate spacetime!
5:08 - where does the claim come from that the metric tensor would be related to the four potential instead of the the field-strenght tensor? as far as i'm concerned, the maxwell equations can be formulated using the field strength tnesor with electric current as source - quite analogously to the Einstein equations which is a differential equation of the metric tensor and the energy-stress tensor is the source... or? Of course everything can also be formulated using the four potential - but what sets it apart?
The number of derivatives is key here. In general relativity you perform the steps: metric-> Levi-Civita connection-> Einstein equation. In electro-magnetism you perform the steps: EM potential A-> EM field F-> Maxwell’s equations. Every step involves a single (multi-dimensional) derivative. So, if you want to combine the two theories into a single formalism you should combine the metric with A, not F.
I didn't know about this idea. It's funny, thanks. Incidentally, the Suskind-Maldacena concept that entangled particles are connected by an Einstein-Rosen bridge seems a natural consequence of the idea that particles themselves are wormholes or black holes. Apparently, within the framework of combining these concepts, wormholes for disentangled particles lead to their own future, other universes to the past, and for entangled ones to each other. That is, if particles (aka wormholes) come together at some point in time, then some process occurs as a result of which the necks of these wormholes begin to close on each other even in the future relative to this moment. That is, two U-shaped wormholes merge into one X-shaped one
Thank you for the video, Sabine. I didn't know that Einstein had thought of the similarity between black holes and particles. I have been looking into the similarity a little bit myself. To "build up elementary particles from energy", my assumption is that elementary particles really are elementary and cannot be built up from smaller energy or charge units, because they have elementary charge (ie indivisible charge). And, whenever an electron is created, a positron is also created.
The current stage obscures the former one. Like changing a triangle to a square. No one will ever be able to see it was a triangle first. Because the square is all you can observe. You cannot look before that.
I don’t feel that we are even close to a theory of everything because of the limits of human observation and technology but these theories are fascinating. Thank you for bringing it to us for free here on youtube. You are doing a great service
You make me want to go back to trying to be a physicist rather than an electrical engineer. I wonder how far someone could take this idea with our modern understanding of physics.
This video did inspire me to develop my own unified theory. It clearly postulates that I will get a more lucid answer if I rely on you to develop a Theory of Everything.
What nobody talks about is the very strong implication hiding in plain sight - the equivalence principle - that not only is standing against gravity indistinguishable from acceleration, but electromagnetic (and other) accelerations should be indistinguishable from curved spacetime.
Trying to visualise what your saying and I think you make a valid point, I'd be interested to hear your definition on (and other) accelerations in greater detail
It always amused me that the demonstration of gravity as a property of space time using a rubber sheet and spherical weights relies entirely on the very thing it's trying to demonstrate, gravity, in order to work. If you took those spheres and the rubber sheet outside the gravitational field of earth it would no longer work - the sheet would not be deflected and the marble would just go in a straight line.
another difficult topic presented in a way to make it easier to understand. always appreciated. the wobbeling of spacetime itself on such small scales could maybe explain how quantum particles are always "popping into existence" and out of it again in the "emptiness" of a vacuum. it would be a little bit similar to the atoms in every tiny piece of matter: rigid on large scales but always moving and jiggeling when observed on their own scale. i would assume that it would be "easier" to explain how the spacetime itself could "generate" any given particle than to explain, how some of these particles can be so stabile even over long timescales.
HELP! You said "matter is really just spacetime curved in a particular way"... SO how now does energy fit into everything? If matter is just spacetime, how is energy related to spacetime ? E= spacetime * C squared ?
Maybe nothing but interactions actually exist. A silly notion, but with our current understanding, it's possible to argue philosophically, and I think that's indicative of how we observe reality more than its nature.
@@SabineHossenfelder More please...? Can we say that the behavior of spacetime at the event horizon is evidence (question one) of the speed of light as spacetime starts collapsing (?) faster than light? As you already know, I'm also really curious what OTHER mechanisms have been proposed, other than QCD? I know, QCD is accepted wisdom... I just don't feel like we can ignore the apparent disconnect between electrons and "strong force."
@@SabineHossenfelder What number or unit, would then be used to quantify spacetime? There would be Kilograms of spacetime ? Or there will be an equation of how many "cubic miles?" of space time, times a constant? = KG ?
I just adore listening to your lovely big brain whirring away. It inspirational for sure and refreshing because you present science so anyone who listens can learn and understand it. Love you!
I find it hard to imagine a universe ex nihilo where it doesn’t ultimately boil down to one substance. I understand that’s part of the appeal for strings but honestly Einstein’s idea seems better!
Either that, or substance and spacetime are what allows the other to exist! That is to say, without substance then spacetime is meaningless and without spacetime then substance is meaningless. If that makes sense. They both prop one another up
I think that strings is just another way to abstract it. Much like how we abstract particle and wave, then we got a duality. It doesn't mean that something is particle or a wave just because they exhibit those behavior. Those something that exhibit the particle-wave duality is just fitting our model of wave and particle at the same time. Since my background is programming, I'd like to think about it as "If it quacks like a duck, then it is a duck", but it can also do other things other than quacking like a duck. But for all intents and purpose, our abstraction just state that it IS a duck (at least indistinguishable from a duck)
Since I was a kid I've always thought the universe had to be some sort of n-dimensional nodal network of cellular automata. But another thought I've had is that maybe it is just sections of Pi (or any irrational number) rearranged into an infinite number of discrete states that create the perception of continuity.
That's already what we have - there is only one "substance" (energy). Spacetime is not a "substance", it's a shape. The conflict is that energy in QM needs to be "smeared out" probabilistically, while energy in GR needs to be point-like. Those are pretty incompatible ideas. String theory looks at GR and says "hey, that shape can be reimagined as a force" (ie: the equivalence principle) and defines a new field (ie: smeared-out probabilistic energy) to implement that force - the graviton. Einstein's idea is kind of going the other direction - reimagining energy as specific twistings within the shape defining spacetime. That still doesn't recreate the "smeared out" probabilistic effect though, so you're going to have an extremely difficult time describing the effects of quantum mechanics within such a framework. I'm not going to claim it's _impossible_ - I certainly don't have the math chops to even attempt to prove that - but it's certainly going to be a lot more challenging than removing the point-like nature of energy under GR (which is already super difficult to do while maintaining mathematical consistency).
This is a fascinating topic, Sabine! I would love to see more content about why charged/uncharged particles exist and how they might arise directly from the fields. Clearly Einstein and these brilliant people have struggled mightily to understand this question.
@@scene2much Her pronunciation of Einstein is more sh than s nowdays. Is that more evolved? She, like most people as they get older, is losing the English traits and heading back to her native language.
I am glad to learn that Einstein's original thinking was for particles to be a form of curved space itself as this aligns with my thinking on the measurement problem and unified theories. Could there be a 3D zero-point-field that is perhaps the surface between virtually charged (+,-) regions and inflating at velocity - c? Particles might exist as an excess of + charged energy that is a precipitate of this field. Spin arising not from actual particle rotation but as an interaction of virtually charged space inflating around the particle. If the production of inflation points are coherent cells (or layers) that expand forever, anything embedded (entangled) in a specific cell becomes superposed with a probabilistic state across a "local" space (regardless of distance), and exhibiting what appears as a "non-local hidden variable". When perturbed, then de-coheres from a particular spatial cell it becomes a quantized state with a defined location.
I've thought for some time that particles are tightly curved versions of something more fundamental. It hadn't occurred to me until now that the more fundamental thing could be spacetime itself (tightly curved or not). A whole new thing to consider! I like that.
Great Video, thank you very much for it! ❤ Two questions: If space(time) now is supposed to be made of _something else_ (strings, loops, networks) and energy (T_mn) is the source of it - shouldn't it somehow _fade_ at higher distances? If the first reason for inventing special and general relativity was the measurement of the constancy of the speed of light - why is time treated as an independent dimension?
Because the combination of space and time together is invariant for all observers. Every location in space is in the past of every other location in space. You can handle this automatically and mathematically with Minkowski spacetime.
@@juliavixen176 I see that it's nice to use time as the fourth dimension. But why shall it be _independent_? We can only chose the velocity in _three_ directions, the velocity in the fourth direction is bound. Time is not independent.
@randerscheinung1 Time is *_not_* independent. This is literally one of the very first things that led to the creation of (what was eventually named) the "Theory of Relativity". Larmor, Poincaré and Einstein were the first to point out that this is a consequence of the Lorentz transformation. Also, velocity is relative and meaningless without a second _whatever_ to compare motion to. Everything is always moving at zero velocity relative to itself. And velocity is always in a straight line. (It's Newton's first law of motion.)
General relativity and quantum mechanics will never be combined until we realize that each individual observer is observing them both at different moments in time. Because causality has a speed limit (c) every point in space where one observes it from will be the closest to the present moment. When one looks out into the universe they see the past which is made of particles (GR). When one tries to look at smaller and smaller sizes and distances, they are actually looking closer and closer to the present moment (QM). The wave property of particles appears when we start trying to predict the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse is what we perceive as the present moment and is what divides the past from the future. GR is making measurements in the observed past and therefore, predictable. It can predict the future but only from information collected from the past. QM is attempting to make measurements of the unobserved future and therefore, unpredictable. Only once a particle interacts with the present moment does it become predictable. This is an observational interpretation of the mathematics we currently use based on the limited perspective we have with the experiments we choose to observe the universe with.
This "other" Einstein unified theory you pointed out is very similar to what the man with the highest measured IQ in the US (Chris Langan) proposed - that matter is gernerated out of spacetime curved in a particular way. He calls his theory the CTMU.
0:27 Einstein was not interested in gravity, his goal was to extend the principle of relativity to non-inertial reference frames as well. In 1907 Einstein started with the classical equivalence principle (gravity/inertia), but soon modified it: gravity suddenly "became equivalent" to the curvature of 4-space, and was replaced by it. 1.For all physical fields, with the exception of the gravitational one, the source of the field does not depend on the quantities characterizing the field itself. This difference is due to the fact that the gravitational field obeys the principle of equivalence and therefore it can be geometrized. Other physical fields do not have this property. 2.However, real gravitational fields are variable in space and time, so there is no global equivalence between them and non-inertial reference frames. In the case of a gravitational field, no global transformation can exclude it and thereby bring the metric to the form of an inertial Cartesian system. This can be done only in an infinitesimal 4-volume in the vicinity of the event P. 3.That is, the strong equivalence principle (the same flow of natural phenomena in the gravitational field and the corresponding non-inertial systems) turns out to be just a dream; and the principle of general covariance, which holds for all 4-coordinate systems without exception, is unreasonable (in GR). 4.Cosmetic additions by Kerr and others will not save GR from singularities while Einstein's theory of gravity is chartered in a Riemannian manifold. Of course, all physicists were aware of the difficulties of GR*, but the experimental data showed in favor of GR**. 5.Unfortunately, only at the end of his life (in the last published article, on the last page of the article) Einstein recognized that the geometrization of gravity is unjustified and prevents the creation of a unified theory: 6."It can be convincingly proved that reality cannot be represented by a continuous field at all. It seems to follow from quantum phenomena that a finite system with finite energy can be completely described by a finite set of numbers - quantum numbers... A purely algebraic theory is required to describe reality." (Einstein, January, 1955). ------------------- *) - 1."There is no complete coincidence of both geometries, however, due to the imaginary nature of one of the coordinates. So, for example, two world points located at zero distance from each other do not necessarily coincide." (Pauli, Theory of Relativity, paragraph 7, 1921). 2."Thus, there are "true" gravitational fields; however, the meaning of this word in general relativity is different than in classical mechanics... The question of in which cases, by choosing a reference point, the gravitational field is destroyed throughout its entire length can, of course, be resolved only by a complete theory." (Born, Theory of Relativity, Chapter VII, paragraph 2, 1922). 3.“The geometry of space in general relativity theory turned out to be another field, therefore the geometry of space in GR is almost the same as the gravitational field.” (Smolin). **) - As a fundamental theory, GR has the ability with just one parameter: r(G)/r=q to predict, explain new physical effects, and amend already known ones. 1.Photon frequency shift in gravitational field Δw/w(0)=q; 2.the angle of deflection of a photon from a rectilinear propagation path =2q, 3.the Newtonian orbit of the planet shifts forward in its plane: during one revolution, a certain point of the orbit is shifted by an angle =3πq, for a circular orbit (eccentricity е=0); in the case of an elliptical orbit - for example, for perihelion displacement, the last expression must be divided by (1-e^2). 4.However, the parameter q is not necessarily a measure of the deviation of the metric from the pseudo-Euclidean one, since in the quantized phase space {“This new type of universe in its other properties resembles Einstein's cylindrical world." (A. Friedmann, "On the curvature of space", 1922).}: q=πr/L[=w/w(pl)], where L is the length of the phase path, r - the corresponding orbital radius: and πr^2=r(G)L. 5.GR/QG predicts a new physical effect: w/w(pl)=q; expression for gravitational radiation from a test body, where w - the frequency of the quanta of the gravity/inertial field (space-time). 6.This effect is actually about gravity/inertial induction (~electro/magnetic induction) and this circumstance may relate electro/magnetic to gravity/inertia at the quantum level: on the one hand, ф(e)=[h/2e]w, and on the other hand, ф(G)=-[h/4πm(pl)]w. 7.This is amenable to physical examination in laboratory conditions at present.
I enjoy your videos due to your knowledge as well as your attractiveness! Today, however, wow, I'm so impressed by your intelligence! Way above me but, nevertheless, amazing!
I find it interesting to learn how Einstein had more theories (and much less successful ones at that). From a historical perspective, this video was incredibly interesting. Yet I also find it interesting how almost every science communicator on RUclips/the internet (even intelligent and educated ones) insists upon using the incorrect analogy for curved spacetime of some ball weighing down a sheet with other balls rolling around it (assuming space and time are linked and curved in the first place). This isn't how 3 or 4-d curvature works. Also, it is using gravity as a force to try to explain how gravity isn't a force (ironically).
A version of this is what I am suggesting below. Maybe some hints at the maths could be found in here somewhere. The biggest (only?) hurdle is assuming gravity to be an attractive force. It can be seen rather as the dissipative force of the elastic solid of spacetime (see Padmanabhan (2004) for an example of ‘elastic solid’ spacetime) as it resists the compressive forces due to quantization. You are already exploring the ‘repulsive’ forces that you are attributing to dark energy (elastic solid spacetime in this view). Why not extend that ‘repulsiveness’ to dissipative gravity? Gravity only appears to be attractive due to the conservation of energy as spacetime is pulling everything apart (the physical source of entropy btw). Another hurdle is assuming supersymmetry is between symmetric particles rather than symmetry between conservative (QCD and QED) and dissipative forces (QED, weak, and gravity). Also, the compression and perturbations of this elastic solid spacetime results in the various ‘fields’ governed by interactions with the various fundamental particles. Strong force is local due to the relative (supersymmetric) stability between conservative and dissipative forces. The weak is the amplified effect of the dissipative force of gravity relative to the strong force(?) and thus also local. Notice QED is in both and is thus the bridge, the connection between elastic spacetime and the quantized particles, the interactions within the solid/liquid colloidal mixture that is our universe. In this view there is no need for singularities, something from nothing, any 'in between', or any of the other fantastical artifacts discussed. Straightforward. Simple. And everything in the universe can be seen as dissipative systems including us. Beautiful.
When Einstein was working on electromagnetism he didn't know or wasn't able to imagine his cosmological constant as dark energy was real. To unify electromagnetism with gravity you may think of normal gravity as the curl operator and dark energy as the divergence operator perhaps?
Just wondering, why at 3:48 do you say "He's tried for 2 years to combine electromagnetism with gravity and it didn't work" While the caption (if, I presume , Einstein's translation) reads: "After ceaseless searching during the past 2 years I now believe to have found the solution"
That's absolutely the biggest one, what is energy? I mean what is it? If matter is just condensed energy, if everything is just energy, then you can't define it in terms of anything else, and you're stuck. Time to go do something else ..
Thanks, I had asked the question in comments on other physics videos, whether magnetic attraction and the attraction of positive/negative electrical charges might also have an underlying explanation involving curved spacetime, like gravity, but I had not seen an answer. It is making progress to hear that the answer is "Well, maybe", at least if I'm understanding correctly. It seems to me (a naive layman) that if magnetic or electical attraction were "forces" and not a pseudo-force like gravity, then they would be akin to the pull of a tow truck that could pull forever, without needing to replenish a fuel source (like the tow truck needing to refill its gas tank). That would seem too much like "free energy".
As usual, a brilliant (notice how I slipped that in) presentation. I just read Einstein's Unfinished Revolution by Lee Smolin. Have you talked about Lee's idea that time is primary and space is emergent.
So if we want to describe a particle we would describe the center of the particle a 0,0,0 in a three dimensional coordinate system Then probability of finding the particle is at x e^-(x^p/2v) / SQRT(2*pi*v) where x is x1, x2, x3 dimension and v is the variance which is derived from uncertainty principle. And p is some factor that describes kurtosis. The problem however when you apply general relativity is that coordinate system is a fabrication of the observer and position is relative to something else. As a consequence you are imposing a coordinate system, which quantum mechanics you can only take one measurement from. Is this distribution real or not. So what if a particle is a black hole. R = 2 μ/c^2. Let’s assume it’s the mass of a Top quark. Its mass is 173 GeV/c2 or About .186 kg/.60223E24 or 0.3-E24 kg G = 66.7E-12 or 20E-36 = μ This is then divided by 1E17 and multiplied by 2 so essentially .4E-51 which is less than a Planck length, so the distance is trivial. But to have a black hole you need a curvature of spacetime in which the gravitons evolve along two dimensions. A point has no dimensions, so that a blackhole cannot be a single graviton or anything that size or smaller because that would be dimensionless. The smallest conceivable black hole would need to have the smallest radius that might result in a blackhole negating QM is ~2.5E-35 or 2.3E-18/c^2 2.3E-18/c^2 = 2*6.67E-11*M/c^2 M= 2.3E-18/.667E-12 = 3.5E-6 kilograms or about 3.5 milligrams. Take 4mg of gold, compress it to a volume 10^93 times smaller than it is, and you can have a black hole, maybe. It would blow up and 100 feet of the surface of the earth would disappear. Blackholes take in mass, they don’t give it back. 3.5E-6kg*0.9E17 = 0.32E12 joules. (About 1/200 the yield of Little boy).
Super coold video. Thank you Sabine! It's just something so inspiring by hearing about Einsteins mistakes and dead ends too. More of these interesting failed ideas from other physicists please!
I'd like to learn more about this idea and hope others are pursuing it. I always wondered what caused Einstein to fail in getting a unified field theory. I wonder if this alternative approach which perhaps uses singularities as the fundamental pieces that make up a quantum universe might be the answer.
![Seungmin "그렇게, 천천히, 우리(As we are)" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/kAzmhLHePqU/mqdefault.jpg)
This video comes with a quiz which lets you check how much you remember: quizwithit.com/start_thequiz/1716012446752x687523319581570800
20/24 🙄😇?
in order for particles to be made out of space-time, space-time would have to really exist as something separate and fundamental, like another quantum field. Is that accepted as fact? Or is space-time just what the pre-20th-century guys were calling the em-field before quantum fields were known?
that is amazing please keep doing these quizzes on your videos
Isn't matter a form of energy and energy is space time
@@derby526 it´s a fun!
I know some people will say it's too technical, while some say it's too dumbed down. I'm here to muddy the waters further and say you are presenting the information just right! Thank you for these well thought out presentations of dense material.
Don’t shy away from the maths! It’s intimidating at first, but the more you are exposed to it you start to see if as just another language that you do not understand fully.
Yeah, but it's TOO just right.
It's also too just kidding...
@@GizzyDillespee 😆
It's not "just right", because many of these ideas are not forgotten, only the ones that are wrong. The Einsteinian antisymmetric metric tensor re-emerges in string theory, and also, the "particles are black holes" idea is realized, except in a quantum context. Einstein's ideas could not be right because they are classical, and he should have known better even back then.
@@annaclarafenyo8185
-Eh. That's your opinion. 😁-
Finding flaws in Einstein's theories isn't disrespectful of Einstein. Improving on his search are actually to honour him.
I agree, when one is at the forefront of new things, tis inevitable that there will be omissions, errors, misunderstandings or even simply ignorance (whether it be accidental or willful) in any materiels produced in any new fields. It's the Scientific Method to test to confirm new ideas. If successful those Ideas stays, if an idea fails, it's up to the scientists to figure out why and either modify as needed or ditch ideas altogether (at least until new data surfaces to warrant revisiting a prior failed idea that may then work with new understanding of the latter times.
The body of Scientific Knowledge is built upon the foundation of fundamentals that adds up to Laws of Physics and Quantum that ultimately leads to the final Unified Theory of Everything. Obviously we do not have all or at least enough of the Fundamentals down pat …yet.
Eventually, with perseverance and due diligence, we will learn more and we will get there.
@@johnk9964 saying there are not flaws is sign of igonarce
@@johnk9964 no i was referring to you
Saying there isn't flaws in Einstein theory is sign of ignorance and math is jack shit to prove
@@johnk9964 and what if we were seeing all wrong what if Einstein was wrong?
These experiments aren't guaranteed
I love when you present little hidden gems like this. I'd never run across this idea and physics history otherwise. Perfect level of technical explanation, as usual too.
That idea that spacetime curled up onto itself is what makes particles is explored in a set of papers by Dr. Howard Perko. He has derived the equations from an idea that spacetime can be represented as hyper surface tension. So it’s not just a membrane, it can also have fluid dynamic properties as well and GR comes out if shear is set to zero. I think he is on the right track and I sincerely hope that you at least take a good look at his papers.
Read my recent Medium article, and feel free to provide feedback. Ties in with your comment. "Grasping Vital Points Most Physicists Misinterpret About Reality"
I'll definitely check it out. Sounds interesting
@@buddypage11 feedback: medium sucks.
@@UnmannedairIt is simple and easy to use, and I am on Substack too. Just opened a long delayed Patreon yesterday.
Curled spacetime on itself like fluid mechanics where particles emerge? It sounds like the infamous "ether". So interesting, I'm going to take a look on this idea
Wonderful, Sabine! Exciting interesting content
Thanks so much, really appreciate your support. (And your thoughtful comments, too!)
@@SabineHossenfelder ☺
@@SabineHossenfelder Hello
Is it possible you could do a video on Einstein's original other unified field theory?
I've never heard of this alternative theory till now will but it's actually right!!
It fits into my Super Unified Field Theory or (SUFT) it fits even better than the one that he's known for but I would like to make sure.
I am attempting to have it get peer-reviewed and I require feedback on it but so far no one wants to have anything to do with it for whatever reason!!
The Reason No One Has Been Able to Come up with a Proper Unified Field Theory, You Need to Quantize Time First!!!!
It's The Key To It All Without It You Are Wasting Your Time Trying!!!
I did send you a copy of my SUFT formula to your website e-mail hoping you might take a look at it!!
There are nine different studies that all have predictions in SUFT for them and it explains their results better and more accurately!!.
I will send you a new e-mail with the studies and the SUFT formula and hopefully you will find it all very interesting..
Thank You
John
It's great to see ANYBODY talking about this finally. But I must point out a very much missing historical point - Weyl got the unification ball rolling in 1918 with an extension of Riemannian geometry in which the length scale was localized as a field. This brings in the A_mu as the "gauge field", which is where the term originated. Weyl's idea doesn't work in 4D because there are no irreducible Lagrange densities that are both coordinate scalars and gauge invariant. However it DOES work in 6D and allows a complete, irreducible solution to the problem. Einstein was right, again. (Look for "Gravitation and Electrodynamics over SO(3,3)" if your are interested. It works in principle for any gauge group, but the calculations have only been done for U(1), which was hard enough by itself.) BTW Pauli showed the KK theory was itself reducible in that any generally covariant theory can be patched onto GR this way. The gravitational and electromagnetic potentials are physically different things after all.
I'm trying to get some work done for a project of mine and I need interesting videos playing and couldn't find any until finally you popped up! I dread what it'll be like 13 minutes from now...
These topics, GR, QFT, and their crossover and history are so important; please keep covering them
This is one aspect of the Wolfram physics project. That maybe particles are not elementary but rather an emergent thing in spacetime.
Their spacetime is actually space, on the form of a graph, and time, in the form of rewrites of the graph.
So it's not fundamentally equations, instead is an operational deception on how space and time actually works.
And particles could then be some kind of "knots" in the graph, analogous to how a knot on a rope is an emergent phenomenon of the rope itself. You can move the knot on the rope but it's still only rope...
I find this exciting as this is an entirely different paradigm to try to tackle the problem of a theory of everything.
Sorta like three space dimensions and one spacetime dimension line up with three forces and one gravity?
only time is fundamental according to SW, while space is emergent and has not exactly 3 dimensions, but only approximately.
WWAVESS 🌊🌊🌊👋👋👋💚💚💚
@@michaelwinter742 I'm mostly sure that is just a coincidence, but maybe not. Maybe the SU(3)xSU(2)xU(1) stops at 3 because of our number of dimensions, but that just seems like a random selection, or, like, asking why gravity is as strong as it is. For now, it just is. But maybe a ToE will show how space and the forces are all together, maybe it won't, only time will tell...
Particles of different wavelengths feel different spacetimes, therefore SW rewriting rules.
Fascinating, can we have more of these technical & detailed video's please. I appreciate they are not for everyone, almost certainly a minority, so maybe a sub-series. This video has enough material for a whole series explaining all the different theories and approaches. Thanks Sabine p.s. keep up the rants, physics needs them.
When you talk about Einstein & show equations, you get excited and talk faster... BUT ! When you talk about Einstein & actual equations, is when us normal humans need you to talk slower !😁
True. I also wish that whenever an equation is shown, there was an explanation for what each letter meant. Otherwise it doesn't make much sense to me.
I come for the authentic Einstein pronounciation
@@ylette I know what many of the letters mean, most of them, even, tho not formally, and it isn't particularly important to the discussion at hand. She points out and explains the parts that are relevant for the viewer, without overloading them with info. Granted, I always think more information is better than less information, so some quick text on the screen about the equations shouldn't hurt.
@@lanorothwolf2184 I think she thinks she gets paid more to add in the h that doesn't need to be there. She only says his name about 600 times a video.
@@ylette That's an entire video in itself. More likely multiple videos. And people would definitely get bogged down in the confusing concepts those variables imply, which would distract from this video's main points.
She used ALGOL/C/Java/... style comment markers to start+end her rant. Just when I thought I couldn't love the channel more!
I don't know how ALGOL is your first example language as it is very obscure, but I do not see a version if ALGOL that uses C-style block comment syntax.
@@gamechannel1271 Lol, I've never even heard of ALGOL -- not that I'm some encyclopedia of programming languages or something.
ALGOL was one of the first system level computer languages. C is somewhat a derivative of that.
@@gamechannel1271 C style comment blocks were borrowed from ALGOL, which came first. I'm a C guy, but calling them C style comments isn't any more accurate than calling them Java style comments.
ALGOL is still in use by physicists.
I'm glad you're keeping Einstein's ideas alive, Sabine. We need to learn from history, both the good and the bad. Btw the idea that matter is the same as space (i.e., "extension") goes back to Descartes. The analytical-geometrical branch of physics (such as GR; as opposed to the thermodynamics-QM branch) is all downstream of Descartes.
if it weren't for Descartes, we'd have no idea where we're at.
@@DrDeuteron Lol. I guess we'd be "uncoordinated"!
I think this is a fantastic video and topic. My appreciation to Sabine for this.
As an undergrad engineering physics major, I read the book "Subtle is the Lord" by Abraham Pais and took the time to learn German specifically so I could read his book about Einstein's later papers. I studied Kaluze-Klein and the Einstien-Rosen papers specifically. I'm not smart enough to work at that level but do hope someone that is continuing with that line "particles and space-time warped in specific ways" idea. I think Sabine is right it is a line of thought that needs to be investigated more.
hypnotic. i nod my head, i smile, and at the end of the exposition i have learned that einstein spent half his life wandering through physics to no avail.
there is a lesson in this: if you must study physics, do it in your spare time, but concentrate on cabinet-making or pottery. you have something to show for your time on earth.
A lot of philosophers would tell you the pots and cabinets will break and be thrown away and your work will soon be forgotten. Even Einstein will be forgotten one day. Don't seek meaning in what you leave behind.
...or violin playing or tax assessments...
I had been considering this theory myself and never knew Einstein thought of it before. It seems like an obvious next step from relativity to describe fundamental particles. I always liked it because it also describes what is happening when you try to move matter throu space. It's like pushing a canoe through water. It takes energy to separate the water at the bow, but you recover that energy when the water comes back together at the stern. Something moving at a constant speed doesn't require additional energy to keep moving. To accelerate, you have to put in energy to open the space in front of the object slightly faster than the energy is recovered at the back. When you try to push it faster, you get to a speed where the water behind can't come back fast enough, and a cavity is left behind the vessel. The faster you go, the longer this cavity is, requiring much more energy to accelerate. Effectively, it's mass grows. This seems to describe Newton's laws and Einsteins laws at once.
Wow, this is exactly what I'm currently researching! It's technically just vacuum GR, but I've found that it seems to explain a lot. I've already overcame the issue Einstein had at 3:01 . I'll send you an email about it. Regarding 5:35 , it could if you discard the cylindrical condition. Regarding 9:45 , Teleparallelism is an equivalent formalism to 1915's GR. Both give the same predictions for vacuum GR, the case where Ricci curvature, torsion, and nonmetricity are 0. Consequently, Kaluza-Klein theory can be reformulated in tetrad formalism with more than one compact space, which can be more complicated than a 1-sphere. I suspect that Teleparallelism's Kaluza-Klein variant is more mathematically elegant looking than 1915's GR's Kaluza-Klein. I can also share with you my reasoning why this can still give rise to quantum effects. It actually has to do with a Superdeterministic formalism of GR I've been working on.
I like these high level videos, it's more contextualized than just a history lesson and connects some dots that aren't obvious to people outside the field
11:12 I've asked scientists about this and gotten goose eggs on it. I've always wondered if matter was based on curved space rather than curved space on matter. I figured it was my craziness. Sabine, you rock!
I’ve been thinking about the theory where our universe might be inside a black hole.
Here are the key points that I thought of (feel free to question everything):
The general idea is that the regions of space, before and after the event horizon, have an opposite arrow of time.
1.External Perspective: From outside, our universe looks like a black hole with an expanding event horizon. As matter falls in, it appears to slow down and redshift, similar to objects approaching a black hole’s event horizon.
2.Internal Perspective: Inside the black hole, time appears to move forward normally for an observer. The universe expands, akin to a white hole, with matter and energy moving outward.
3.Symmetry: There’s a symmetry between the perspectives. Outside observers see our universe as a black hole. Inside a black hole, the expanding region looks like our observable universe.
4.Entropy: From the inside, the universe’s expansion increases entropy, consistent with the second law of thermodynamics. This aligns with how we see our universe’s entropy increasing.
5.Evidence: To test this, we could look for subtle signs in the cosmic microwave background or gravitational waves that might indicate a central singularity or different entropy dynamics.
If we are, then it's the strangest black hole... so strange that it doesn't look like one. ;-)
When I first heard of how gravity works according to General relativity, I had the thought that what we observe as matter is propably just space curvature. And that there's no matter needed that curves space, but it's space curvature itself that creates the illusion of matter. I was also sure that someone else must have had this thought before me. Hearing now that it was Einstein himself who thought of it this way, makes me a bit proud of my self 😊
Thanks for this video, Sabine!
It’s so funny to listen to you - i understand nothing, but it’s like watching Spaceship Enterprise
Starship Enterprise 😉
I enjoy this format where you talk about ideas from the past, who had them, who else build upon them, in a quasi-chronological order. I find it very interesting to learn about how science evolved as well as how old some of the ideas are. If you decide to make more of these for other topics, I'm in!
I was wondering about that a few years back, did some back of the envelop calculations and it turns out it's at leas theoretically possible and when you reason from first principles it's even likely that particles are black holes. What is more important is the fact that a black hole IS in essence a single particle/object. Whatever it causes, classical particles cause it too just with lower magnitude - think frame dragging. Protons, electrons etc. also have a frame dragging effect, just a lot smaller - think along the line of spin.
Wonderful video, Sabine. Thank you very much for taking the time to expound upon something that, as a lay-person who cannot read German, I have wondered about for decades.
Thanks for clearing that up
I'm speaking as an educator when I say this: It is a shame that we don't teach students in primary school (or secondary school) much of anything about the history of science (or mathematics). It has been my position for some time now they we should reintroduce curriculum for the instruction on the history of science and mathematics, because I have become convinced that, not only was it a mistake to remove these subjects in the first place, but also we can begin to overcome the fundamental road blocks we run into again and again with so many students when it comes to math and science. We now have a generation of educators who also did not learn or study the history of math and science disciplines. When I first decided to independently study the material for a college level history of mathematics course, almost immediately I found myself wondering why this class isn't taught in primary school, or at the very least made a prerequisite for most (if not all) undergraduate college degrees. I also found myself lamenting the fact that I had been deprived of what I would could consider an essential foundation of general education. I'm bringing this up because the video is about history of the development of Einstein's lesser known ideas, which it would be expected that only specialists would be aware of, for the most part, because usually only students who are studying the relevant, narrowly focused subject matter are though to have need of the benefit of exposure to the historical context in which the key ideas in their field or discipline developed. It is extremely useful, and greatly aids in students' understanding and retention, I believe, when we pair the fundamental concepts with exposure to the contemporary history when this ideas, concepts, and theories were being formulated. If nothing else, I strongly believe this will be of great benefit, even if only because a layer of abstraction in how we teach math a science will be removed and replaced with something entirely concrete, because no one actually learn BETTER when things are presented to them as pure abstractions as opposed to something concrete. Education shouldn't be merely about preparing current and future generations to become good little workers, as if our only purpose is to become one of but many useful and productive, but ultimately insignificant, and eminently replaceable parts in our self-perpetuating, self-justifying system. The point, or goal of education, is to teach new (and sometimes old) people how to become competent, and most importantly, confident that they will be able to understand and navigate the larger world, and have to tools to handle NOVEL situations that will INEVITABLY arise in the myriad so-called "real life" situations.
Is there an explanation, why gravity and electromagentism follow the same law of distance, namely, decrease with the square of the distance
3 space dimensions, constant flow from source - one dimension for distance, 2 left for area of effect flow distributes to
Geometry. If you take something that follows the inverse square law (e.g. light from a light bulb) and constrain it to only travel in one dimension (e.g. by putting the bulb in a flashlight), its intensity will drop off fairly linearly instead of exponentially.
If you assume Gauss's law, that implies an inverse square law. The math is approachable, like Calc III level, it's a good exercise to show that yourself.
To add on to others comments, imagine the strength of the force spreading out in all directions. If the strength only depends on distance, all the points that feel the same strength will be the same distance away. Now, all the points that are the same distance from some single given point form a sphere (in 3 spacial dimensions), and so the force needs to cover the whole area of the sphere. As the distance increases, the area of the sphere increases (as r^2), and so the strength of the force needs to spread out more to cover the whole area. So if it only depends on distance, and gets weaker the further you get, the only real option is for it to scale as 1/r^2. Notice this works for both EM force and gravity. It doesn't for the two nuclear forces as the weak force doesn't scale with solely distance like that (at least within its range), and the strong force increases in strength as the distance increases.
Yes. It's because both gravity and EM are long-range forces (compared to the nuclear forces), i.e. they can be observed at macroscopic distances. Thus, at a distance r from a mass or a charge, their gravitational or electric flux is diluted over the surface of the 3-dimensional ball surrounding the mass/charge. That surface is a 2-dimensional sphere with area 4 pi r^2. The force is proportional to the flux (area-)density, i.e. the flux divided by that area, which is why you get an r^2 in the denominator in both cases.
So in summary, both forces are long ranged and we live in three spatial dimensions, that's why.
Thank you Sabine. I have been interested in the black hole electron theory and the kaluza-klein theory for some time now, and I appreciate your coverage of Einstein's original unified field theory. I had not heard about it in this manner before. Have you heard about the Wolfram physics project? I think it could make an interesting video, and it has some interesting connections to Einstein's unified field theory.
Einstein's relativity was so dammed elegant that he couldn't believe the quantum world was any less elegant. But I'm no Einstein..or Hossenfelder for that matter, great videos thank you
QFT is very elegant. That was never Einstein's complaint. His complaint was primarily about the probabilistic nature of quantum mechanics, but that doesn't really impact it's elegance - just it's intuitiveness. There's a reason he couched his complaints in religious ideology ("God does not play dice") rather than any sort of elegance argument. He was smarter than that.
> QM is going to turn out exactly as he would have been satisfied.
Doubtful. There are good reasons to believe QM can not be built from any non-quantum theory. "Good reasons" are not proof of course, but they're also not nothing.
> Not sure why some are trying to quantise gravity.
Because there is no experimental or even theoretical basis for trying to go the other direction. There's only arguments based on "classical is more intuitive!", but intuition has tended to serve us pretty poorly under both QM and GR (hell intuition was already serving us kind of poorly under Maxwell's fully-classical rendition of EM).
Forget the equations that may suggest matter is spacetime, what does that statement or that idea even mean?
@@lmff620 > what does that statement or that idea even mean?
That's the kind of question we've just had to learn to live with when it comes to quantum mechanics. The only meaning we get out of it is often "the math matches experiments so yay".
Trying to assign _meaning_ to what we find is something philosophy has been struggling with ever since we proved that quantum effects are real and unavoidable. We really, really want to have an human-scale intuition - a "meaning" - for quantum mechanics and there just isn't one.
@LisaBlooper > because you cannot fathom what it could (not just what it would) look like
Correct. Specifically, I cannot fathom what it could look like that doesn't disagree with established experimental evidence.
I'm not God to be sure. As I already stated, I can't _prove_ that it's impossible. But I do find it extremely doubtful. Some random person's "I think it could be this!" comment on the internet is not anywhere close to sufficient to erase or even reduce my doubt.
> see Penrose for getting started.
The difference is that Penrose does his homework. When he presents something, he has the math to back it up. Sure, he sometimes still pulls ideas out of thin air just because they "make sense" to him, but he also ensures that his ideas make sense within the context of known experimental evidence and existing well-tested theories.
By comparison you're trying to push an idea that _Albert Einstein_ couldn't make work. That he couldn't make work with only electromagnetism, before we knew about the strong and weak forces.
I'm willing to bet you haven't done your homework as Penrose would have.
> incorrect
In what way? Where is this theoretical basis you believe exists? Again "I think it might be!" is not a theoretical basis - that's just an opinion. Build a theory on that (or point me to one if somebody's already done it) and I'll be happy to admit I'm wrong. Serious theories only please - I'm not talking about a random Thunderf00t video or similar that's just as much wishful thinking as your own assertion.
> not to mention
I don't have a clue what anything in this paragraph means. That's a lot of words that don't seem to say anything. Doing what with my hands exactly...?
> "a particle in 2 places at one time"
I'm not sure if this is just more of the woo as it's in the same paragraph, but this particular type of phrasing is fairly common shorthand for describing uncertainty in lay terms. Obviously it's not correct, but perfect correctness is not the point when you're trying to describe complex topics in a simplified fashion.
> there is something much more profoundly different with going in g>q direction than with going in q>g direction
Which is both subjective, and 100% irrelevant. The universe gives exactly zero poops what you or I or anyone else believes is "more profound". It works how it works whether we like it or not.
> think a little bit deeper about what the difference actually is
No, because I don't care. What I care about is whether any theory matches experiment. Concepts like being "profound" or "intuitive" or "makes sense to me" do not really interest me in any way.
What I want to see is the math. Ideally I'd like to see the experiments, though I'm aware that our experimental capabilities are not anywhere close to being able to probe the energies needed so for now I'd settle for "if we had unobtainable amounts of energy, here's the experiment we _could_ perform". Maybe with some simulations to show that the proposal is at least plausible despite not being able to test it directly yet.
What I'm never going to be interested in is "I think this way is more profound!", especially when it contradicts the existing well-proven theories. But hey, at least you've (so far) only contradicted theory and not experiment - you're doing better than most.
@LisaBlooper haha I often wonder if this is a battle between GR and QM or between determinists and probabilists. (Which means they don't like the philosophical implications of the other theory) The score is 3 to 1 for QM though.
Thanks!
So theory of everything might postulate that elementary particles do not actually exist? So that any elementary particle can be broken down to some field curvature? 🎉
They would exist in the same sense as you and I exist.
Well, yes, and no. They would exist but not be elementary, in the sense that they'd actually be made of something else, that being space-time.
Wow ....does this mean intence gravity makes spacetime go round n round at boackhole horizon and eventually spaghettified spacetime breaks into small spacetime chunks or strings?
👍@@SabineHossenfelder
@@SabineHossenfelderSabinne i love your perspective and humor, however, i would also love if you injected some philosophy into it as well. For example. If you can marry physicalism and existence monism with field theory, you can get a theory of everything. I dont believe matter is emergent but thats because my definition of matter is simply that which is spatial, empirically verifiable and changes.
This was a clear explanation to all. but allowing those with some further understanding to see the maths and visualise the concepts. The discourse about what our intelligent friend was thinking later on is greatly appreciated.
The way you talk with your mouth nearly close is hypnotic.
Amazing skill. ❤
Any Australian, too....
This was fantastic. Sabine explained some of the topics we hear about in a way that was understandable.
Didn't realise Einstein followed through on this. I came to this conclusion myself too, wrote a book detailing how this makes sense back in 2022 actually. Funny, nice to see Einstein thought it was a good enough to dedicate the rest of his life to
I LOVE it when Sabine "rants"! 🤩 ! More ranting please! And more of these awesome general relativity/ black hole / Einstein videos... such a COOL topic,
What a wonderful video and article! Thank you, Sabine.
Fascinating video! You were going so fast that it was hard to keep up. But there were several connections that caught my attention. I'll have to replay the video to refresh my memory of what they were. But one of the later ones in the video was the mention of spin 1/2 in relation to the Kaluza-Klein (KK) theory, which didn't work, as the KK didn't incorporate it, if I interpreted what you said correctly. But then you mentioned that KK (or presumably even higher dimensional variants of it) can work if supersymmetry is incorporated. It's been so long since I read various 1980's and 1990's books on supersymmetry and superstrings, that I either didn't know about that connection or had forgotten about it.
Here's an example sentence:
"The spacetime tensor, denoted by gμν, describes the intricate fabric of space and time, encoding the gravitational field and curvature of the universe, and is a fundamental component in the quest for a simple unified theory that reconciles general relativity with quantum mechanics."
And here's a simple paragraph on a unified theory:
"A simple unified theory, often referred to as a 'theory of everything,' seeks to merge the principles of general relativity, which govern the large-scale universe, with the laws of quantum mechanics, which govern the behavior of subatomic particles. This theory would provide a consistent explanation for all phenomena in the universe, from the smallest particles to the vast expanse of cosmic structures. The development of a unified theory is an active area of research, with approaches such as string theory and loop quantum gravity offering promising avenues for unifying our understanding of the universe."
- scratches head... huh.
This is how the term "theory of everything" is used today, but Einstein wasn't a big fan of quantum physics. He wanted to explain the quantization of matter (as with it having discrete units, particles) but he probably assumed that this entire quantum mechanics business would be replaced by something else sooner or later.
define "promising".
@@DrDeuteron that's an ai generated comment, I wouldn't know a tensor from a black hole
@@aaronjennings8385 That's funny. Does AI know that "promising" figuratively means "it will likely deliver", but it's literally correct also for "lying con-job", as in both cases, promises are made.
@DrDeuteron ai suffers from pareidolia, a chronic hallucinatory/delusions complex... it's subtle sometimes. Occasionally rather obvious
Nice video. For 5+ years I have been rambling about my stupid idea that matter and energy are simply made out of space. Good to know Einstein had the idea as well so it's not complete lunacy. Not sure why just about everyone seems to have forgotten about it. It explains so much when you start thinking of the consequences of it.
Many generations of physicists since Einstein have thought about this. Whether it is space-time knots or some other thing, it is not something that was forgotten. It just has never led to a better understanding. I don't know if it is wrong or right, but it is an idea that never entirely dies.
Back when I was in mathematical physics seminars in university, my pet idea was trying to look at field theories on lattices with a fundamental length scale. I still think it is a good idea, but as a middling mathematician and a middling physicist I was never able to get any of the ideas to work out.
I always kind of hated QFT at the time, despite finding the math interesting, mostly because the combinatorial explosion when you increase the size of a system always made me uncomfortable. It always felt to me like the mathematics was trying to tell us this isn't the final answer. Like Ptolemaic epicycles on epicycles.
This idea is being developed ruclips.net/video/jyFvxN0OPG8/видео.html
but the combinatorial explosion only happens when solving the equations using perturbation theory (also known as Feynman graphs in this context). It's not in the field equations themselves.
@@deinauge7894 Maybe my lack of familiarity (I only did pretty basic quantum chemistry stuff calculating electron wave functions with lumped nucleon models), but the way that symmetry and anti-symmetry are normally set up involves additional position variables for every additional electron, and constraints involving every permutation of the fermions. And my brief experience with second quantization didn't really seem any less complicated (quite the contrary in fact).
It's possible I got a bad/incomplete impression, though. Like I said, I wouldn't say I was fantastic at it by any means.
Could you develop as you said @10:51 that we can get a spin 1/2 field introducing supersymmetry within Kaluza-Klein theory?
Dirac again!
That guy was fundamental too. Newton. Einstein. Feynman. .... Feels like Dirac should be here too, but all I've got is the fa 13:02 ct (okay. my perception) that he comes up all the time. I don't understand really. But he's always there when any teachers get down into the guts of physics. ... that's it. That's all I've got. 🤦♂️
I love this channel!❤👍👀
Don’t forget Euler! More mathematics than physics, but still hugely important!
Dirac put special relativity into Schrodinger's equation and it made a smiley face.
Dirac was probably the second greatest physicist of the 20th century. It’s a mystery to me why he (like James Clerk Maxwell before him) aren’t household names.
@@kylarirons2236 There's basically an Euler [Something] for every field in math or physics.
@@JonS because you need to be in grad school to appreciate why his equation is such a banger. And his lectures on QM, where decides the Poisson Bracket is a commutator with some imaginary non-zero value are...pretty abstract.
Sabine, if you haven't already seen it, you might be interested in Hadley's work, "The Logic of Quantum Mechanics Derived from Classical General Relativity". This would also dovetail with your research in superdetermisim. In later papers he also shows that spin 1/2 emerge if certain conditions are satisfied. I always found this research interesting.
If virtual particles were virtual micro black holes, it might explain spooky action at a distance using EPR=ER since they'd could be created in pairs and maintain entanglement. It's my view that this would be a neat explanation to the double slit experiment.
Thank you Sabine, I have greatly appreciated this video, very interesting and informative. And your channel is one of the few where one can listen to the correct pronounciation of “Schwarzschild” 😉
I'm not fat, my spacetime is curved in a particular way
You have a lot of potential. But no kinetic. :D
I'm not plastered, my liver is a sofa cushion.
Gems, all!
And you attract bodies. Could be worse, right?
spacetime curves in response to massive bodies bro
This was a wonderful exposition connecting so many interesting ideas and developments of the last 100 yrs. Whether a theory worked or not is one question. Whether a theory is a mathematical continuation or unification of something else is another. Very interesting set of thought experiments and mathematical models!!
Dear Sabine: thank you for posting this video and discussing Einstein's paper. I have unironically downloaded the paper and I am working on it right now to incorporate some of its ideas into my work.
You are doing more for science than all of science. Revolution.
Is there an explanation, why gravity and electromagentism follow the same law of distance, namely, decrease with the square of the distance?
A simple explanation is that they propagate in a sphere from the source, and the area of a sphere is proportional to the square of the radius.
@@d95mback makes sense, thanks
Yes, they are both long-range forces which means the force (of a point mass) falls with the inverse or the surface of a sphere, that scales as R^2. This also tells you that in any other number of dimension the force law goes with a different power, and that in general it depends on the geometry of the space. (The strong and weak nuclear force are short-range interactions and do not follow this law.)
Is this not a good argument against extra dimensions (side glance at string theory), even very weenie tiny small ones?
Or at the very least, an argument that gravity/electromagnetism only interact in our three spatial dimensions?
The strong nuclear force obeys the inverse square law too
Hi Sabine! Love your videos and it's great that people like you talk about science to the general public including laymen like me. I signed up to Brilliant thanks to you 😄. I'm slowing making my way to your quantum mechanics' course.
I am curious though, whether quantum field theory has any relationship to this topic? Say for example, the specific wave packet in an electron field is what curves spacetime? Or it's interaction with the Higgs field is what curves spacetime?
From my perspective, there's certainly similarities between matter arising from spacetime, and the vibrations in fields which permeate spacetime!
Me, hearing that Einstein finished his masterwork at 37 when I haven't even started mine
It’s too late
5:08 - where does the claim come from that the metric tensor would be related to the four potential instead of the the field-strenght tensor? as far as i'm concerned, the maxwell equations can be formulated using the field strength tnesor with electric current as source - quite analogously to the Einstein equations which is a differential equation of the metric tensor and the energy-stress tensor is the source... or?
Of course everything can also be formulated using the four potential - but what sets it apart?
The number of derivatives is key here.
In general relativity you perform the steps: metric-> Levi-Civita connection-> Einstein equation.
In electro-magnetism you perform the steps: EM potential A-> EM field F-> Maxwell’s equations.
Every step involves a single (multi-dimensional) derivative. So, if you want to combine the two theories into a single formalism you should combine the metric with A, not F.
I didn't know about this idea. It's funny, thanks. Incidentally, the Suskind-Maldacena concept that entangled particles are connected by an Einstein-Rosen bridge seems a natural consequence of the idea that particles themselves are wormholes or black holes. Apparently, within the framework of combining these concepts, wormholes for disentangled particles lead to their own future, other universes to the past, and for entangled ones to each other. That is, if particles (aka wormholes) come together at some point in time, then some process occurs as a result of which the necks of these wormholes begin to close on each other even in the future relative to this moment. That is, two U-shaped wormholes merge into one X-shaped one
Kinda sounds like how chromosomes work, which feels strange
Sabine is great for old solid state physics guys like me. I continue to be amazed at what she makes (mostly) understandable for me.
It does "feel right" that everything is some manifestation of space-time...making space/matter/energy convertable.
Space is not convertable. Matter and energy are within the canvas of gravity.
Thank you for the video, Sabine. I didn't know that Einstein had thought of the similarity between black holes and particles. I have been looking into the similarity a little bit myself. To "build up elementary particles from energy", my assumption is that elementary particles really are elementary and cannot be built up from smaller energy or charge units, because they have elementary charge (ie indivisible charge). And, whenever an electron is created, a positron is also created.
The current stage obscures the former one.
Like changing a triangle to a square. No one will ever be able to see it was a triangle first. Because the square is all you can observe. You cannot look before that.
Thank you for the video.
I don’t feel that we are even close to a theory of everything because of the limits of human observation and technology but these theories are fascinating. Thank you for bringing it to us for free here on youtube. You are doing a great service
You make me want to go back to trying to be a physicist rather than an electrical engineer. I wonder how far someone could take this idea with our modern understanding of physics.
EE pays the bills way better.
This video did inspire me to develop my own unified theory. It clearly postulates that I will get a more lucid answer if I rely on you to develop a Theory of Everything.
What nobody talks about is the very strong implication hiding in plain sight - the equivalence principle - that not only is standing against gravity indistinguishable from acceleration, but electromagnetic (and other) accelerations should be indistinguishable from curved spacetime.
Trying to visualise what your saying and I think you make a valid point, I'd be interested to hear your definition on (and other) accelerations in greater detail
I don't know anything about physics but I love hearing you talk
It always amused me that the demonstration of gravity as a property of space time using a rubber sheet and spherical weights relies entirely on the very thing it's trying to demonstrate, gravity, in order to work. If you took those spheres and the rubber sheet outside the gravitational field of earth it would no longer work - the sheet would not be deflected and the marble would just go in a straight line.
Gravity because gravity #qed
It's kind of a dumb way to demonstrate it, for sure.
I'm so glad someone else has mentioned this. A disclaimer about this demonstration should always accompany it, yet I've never seen one.
another difficult topic presented in a way to make it easier to understand. always appreciated. the wobbeling of spacetime itself on such small scales could maybe explain how quantum particles are always "popping into existence" and out of it again in the "emptiness" of a vacuum. it would be a little bit similar to the atoms in every tiny piece of matter: rigid on large scales but always moving and jiggeling when observed on their own scale.
i would assume that it would be "easier" to explain how the spacetime itself could "generate" any given particle than to explain, how some of these particles can be so stabile even over long timescales.
HELP! You said "matter is really just spacetime curved in a particular way"... SO how now does energy fit into everything? If matter is just spacetime, how is energy related to spacetime ? E= spacetime * C squared ?
Maybe nothing but interactions actually exist. A silly notion, but with our current understanding, it's possible to argue philosophically, and I think that's indicative of how we observe reality more than its nature.
Basically, yes, that's what it would mean
@@SabineHossenfelder More please...? Can we say that the behavior of spacetime at the event horizon is evidence (question one) of the speed of light as spacetime starts collapsing (?) faster than light?
As you already know, I'm also really curious what OTHER mechanisms have been proposed, other than QCD? I know, QCD is accepted wisdom... I just don't feel like we can ignore the apparent disconnect between electrons and "strong force."
@@AllatumD 99% of mass of the proton/neutron are just gluons interacting, so why not just toss in the last 1% as well?
@@SabineHossenfelder What number or unit, would then be used to quantify spacetime? There would be Kilograms of spacetime ? Or there will be an equation of how many "cubic miles?" of space time, times a constant? = KG ?
I just adore listening to your lovely big brain whirring away. It inspirational for sure and refreshing because you present science so anyone who listens can learn and understand it. Love you!
I find it hard to imagine a universe ex nihilo where it doesn’t ultimately boil down to one substance. I understand that’s part of the appeal for strings but honestly Einstein’s idea seems better!
Either that, or substance and spacetime are what allows the other to exist! That is to say, without substance then spacetime is meaningless and without spacetime then substance is meaningless. If that makes sense. They both prop one another up
This is an interesting point to hold onto… perhaps an essential one! Thank you…
I think that strings is just another way to abstract it. Much like how we abstract particle and wave, then we got a duality. It doesn't mean that something is particle or a wave just because they exhibit those behavior. Those something that exhibit the particle-wave duality is just fitting our model of wave and particle at the same time. Since my background is programming, I'd like to think about it as "If it quacks like a duck, then it is a duck", but it can also do other things other than quacking like a duck. But for all intents and purpose, our abstraction just state that it IS a duck (at least indistinguishable from a duck)
Since I was a kid I've always thought the universe had to be some sort of n-dimensional nodal network of cellular automata. But another thought I've had is that maybe it is just sections of Pi (or any irrational number) rearranged into an infinite number of discrete states that create the perception of continuity.
That's already what we have - there is only one "substance" (energy). Spacetime is not a "substance", it's a shape.
The conflict is that energy in QM needs to be "smeared out" probabilistically, while energy in GR needs to be point-like. Those are pretty incompatible ideas.
String theory looks at GR and says "hey, that shape can be reimagined as a force" (ie: the equivalence principle) and defines a new field (ie: smeared-out probabilistic energy) to implement that force - the graviton.
Einstein's idea is kind of going the other direction - reimagining energy as specific twistings within the shape defining spacetime. That still doesn't recreate the "smeared out" probabilistic effect though, so you're going to have an extremely difficult time describing the effects of quantum mechanics within such a framework. I'm not going to claim it's _impossible_ - I certainly don't have the math chops to even attempt to prove that - but it's certainly going to be a lot more challenging than removing the point-like nature of energy under GR (which is already super difficult to do while maintaining mathematical consistency).
This is a fascinating topic, Sabine! I would love to see more content about why charged/uncharged particles exist and how they might arise directly from the fields. Clearly Einstein and these brilliant people have struggled mightily to understand this question.
I love the way Sabine speaks.
Could be british royalty ;)
Look at her videos from years and years ago and you'll notice that her English speaking has evolved. I leave that as an exercise to the reader.
@@scene2much Nobody was saying it were bad, it only sounds a bit posh and snobbish :)
aren't we all?..
@@scene2much Her pronunciation of Einstein is more sh than s nowdays. Is that more evolved? She, like most people as they get older, is losing the English traits and heading back to her native language.
I am glad to learn that Einstein's original thinking was for particles to be a form of curved space itself as this aligns with my thinking on the measurement problem and unified theories. Could there be a 3D zero-point-field that is perhaps the surface between virtually charged (+,-) regions and inflating at velocity - c? Particles might exist as an excess of + charged energy that is a precipitate of this field. Spin arising not from actual particle rotation but as an interaction of virtually charged space inflating around the particle. If the production of inflation points are coherent cells (or layers) that expand forever, anything embedded (entangled) in a specific cell becomes superposed with a probabilistic state across a "local" space (regardless of distance), and exhibiting what appears as a "non-local hidden variable". When perturbed, then de-coheres from a particular spatial cell it becomes a quantized state with a defined location.
This is one I actually wondered, myself, until Hawking radiation showed they should disintegrate almost instantaneously.
That was one of the best seqes i have ever seen, Sabine. Cogratulations. You just sold me on Brilliant.
Friggin’ Einstein that guy every time I think I’ve got a good idea I find that fuzzy headed patent clerk was already there
Yeah, he stole your great idea ..
I've thought for some time that particles are tightly curved versions of something more fundamental. It hadn't occurred to me until now that the more fundamental thing could be spacetime itself (tightly curved or not).
A whole new thing to consider! I like that.
Is awesome how you make a video of dense topic so light and enjoyable.
Great Video, thank you very much for it! ❤
Two questions: If space(time) now is supposed to be made of _something else_ (strings, loops, networks) and energy (T_mn) is the source of it - shouldn't it somehow _fade_ at higher distances? If the first reason for inventing special and general relativity was the measurement of the constancy of the speed of light - why is time treated as an independent dimension?
Because the combination of space and time together is invariant for all observers. Every location in space is in the past of every other location in space. You can handle this automatically and mathematically with Minkowski spacetime.
@@juliavixen176 I see that it's nice to use time as the fourth dimension. But why shall it be _independent_? We can only chose the velocity in _three_ directions, the velocity in the fourth direction is bound. Time is not independent.
@randerscheinung1 Time is *_not_* independent. This is literally one of the very first things that led to the creation of (what was eventually named) the "Theory of Relativity". Larmor, Poincaré and Einstein were the first to point out that this is a consequence of the Lorentz transformation.
Also, velocity is relative and meaningless without a second _whatever_ to compare motion to. Everything is always moving at zero velocity relative to itself. And velocity is always in a straight line. (It's Newton's first law of motion.)
It's so weird with all the English media I consume to hear someone pronounce Einstein's name correctly.
I actually love the detail and knowledge level of this video.
I had that thought recently that the whole universe and everything in it was just waves of spacetime, and everything started making sense 😂
General relativity and quantum mechanics will never be combined until we realize that each individual observer is observing them both at different moments in time. Because causality has a speed limit (c) every point in space where one observes it from will be the closest to the present moment. When one looks out into the universe they see the past which is made of particles (GR). When one tries to look at smaller and smaller sizes and distances, they are actually looking closer and closer to the present moment (QM). The wave property of particles appears when we start trying to predict the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse is what we perceive as the present moment and is what divides the past from the future. GR is making measurements in the observed past and therefore, predictable. It can predict the future but only from information collected from the past. QM is attempting to make measurements of the unobserved future and therefore, unpredictable. Only once a particle interacts with the present moment does it become predictable. This is an observational interpretation of the mathematics we currently use based on the limited perspective we have with the experiments we choose to observe the universe with.
This "other" Einstein unified theory you pointed out is very similar to what the man with the highest measured IQ in the US (Chris Langan) proposed - that matter is gernerated out of spacetime curved in a particular way. He calls his theory the CTMU.
This is the best video you’ve made so far, by the way when are you coming back to UK? I loved your talk at Oxford
Eveytime Sabine says "Einstein" I take a shot
RIP
I watched so many English science channels that I'm not used anymore to hear his name pronounced correctly 😅
If that's the case, you must be really drunk by now.
That guy again?
@@kevin9218 I'm typing from the afterlife
0:27 Einstein was not interested in gravity, his goal was to extend the principle of relativity to non-inertial reference frames as well. In 1907 Einstein started with the classical equivalence principle (gravity/inertia), but soon modified it: gravity suddenly "became equivalent" to the curvature of 4-space, and was replaced by it.
1.For all physical fields, with the exception of the gravitational one, the source of the field does not depend on the quantities characterizing the field itself. This difference is due to the fact that the gravitational field obeys the principle of equivalence and therefore it can be geometrized. Other physical fields do not have this property.
2.However, real gravitational fields are variable in space and time, so there is no global equivalence between them and non-inertial reference frames. In the case of a gravitational field, no global transformation can exclude it and thereby bring the metric to the form of an inertial Cartesian system. This can be done only in an infinitesimal 4-volume in the vicinity of the event P.
3.That is, the strong equivalence principle (the same flow of natural phenomena in the gravitational field and the corresponding non-inertial systems) turns out to be just a dream; and the principle of general covariance, which holds for all 4-coordinate systems without exception, is unreasonable (in GR).
4.Cosmetic additions by Kerr and others will not save GR from singularities while Einstein's theory of gravity is chartered in a Riemannian manifold.
Of course, all physicists were aware of the difficulties of GR*, but the experimental data showed in favor of GR**.
5.Unfortunately, only at the end of his life (in the last published article, on the last page of the article) Einstein recognized that the geometrization of gravity is unjustified and prevents the creation of a unified theory:
6."It can be convincingly proved that reality cannot be represented by a continuous field at all. It seems to follow from quantum phenomena that a finite system with finite energy can be completely described by a finite set of numbers - quantum numbers... A purely algebraic theory is required to describe reality." (Einstein, January, 1955).
-------------------
*) -
1."There is no complete coincidence of both geometries, however, due to the imaginary nature of one of the coordinates. So, for example, two world points located at zero distance from each other do not necessarily coincide." (Pauli, Theory of Relativity, paragraph 7, 1921).
2."Thus, there are "true" gravitational fields; however, the meaning of this word in general relativity is different than in classical mechanics... The question of in which cases, by choosing a reference point, the gravitational field is destroyed throughout its entire length can, of course, be resolved only by a complete theory." (Born, Theory of Relativity, Chapter VII, paragraph 2, 1922).
3.“The geometry of space in general relativity theory turned out to be another field, therefore the geometry of space in GR is almost the same as the gravitational field.” (Smolin).
**) - As a fundamental theory, GR has the ability with just one parameter: r(G)/r=q to predict, explain new physical effects, and amend already known ones.
1.Photon frequency shift in gravitational field Δw/w(0)=q;
2.the angle of deflection of a photon from a rectilinear propagation path =2q,
3.the Newtonian orbit of the planet shifts forward in its plane: during one revolution, a certain point of the orbit is shifted by an angle =3πq, for a circular orbit (eccentricity е=0); in the case of an elliptical orbit - for example, for perihelion displacement, the last expression must be divided by (1-e^2).
4.However, the parameter q is not necessarily a measure of the deviation of the metric from the pseudo-Euclidean one, since in the quantized phase space {“This new type of universe in its other properties resembles Einstein's cylindrical world." (A. Friedmann, "On the curvature of space", 1922).}: q=πr/L[=w/w(pl)], where L is the length of the phase path, r - the corresponding orbital radius:
and πr^2=r(G)L.
5.GR/QG predicts a new physical effect: w/w(pl)=q; expression for gravitational radiation from a test body, where w - the frequency of the quanta of the gravity/inertial field (space-time).
6.This effect is actually about gravity/inertial induction (~electro/magnetic induction) and this circumstance may relate electro/magnetic to gravity/inertia at the quantum level: on the one hand, ф(e)=[h/2e]w, and on the other hand, ф(G)=-[h/4πm(pl)]w.
7.This is amenable to physical examination in laboratory conditions at present.
I enjoy your videos due to your knowledge as well as your attractiveness! Today, however, wow, I'm so impressed by your intelligence! Way above me but, nevertheless, amazing!
I find it interesting to learn how Einstein had more theories (and much less successful ones at that). From a historical perspective, this video was incredibly interesting. Yet I also find it interesting how almost every science communicator on RUclips/the internet (even intelligent and educated ones) insists upon using the incorrect analogy for curved spacetime of some ball weighing down a sheet with other balls rolling around it (assuming space and time are linked and curved in the first place). This isn't how 3 or 4-d curvature works. Also, it is using gravity as a force to try to explain how gravity isn't a force (ironically).
(paradoxical) instead of (ironically) would, perhaps, sounds better.
My cat's breath smells like cat food.
Just eaten - a full crunchy carrot soup. Fare thee well - on life's journey
A version of this is what I am suggesting below. Maybe some hints at the maths could be found in here somewhere.
The biggest (only?) hurdle is assuming gravity to be an attractive force. It can be seen rather as the dissipative force of the elastic solid of spacetime (see Padmanabhan (2004) for an example of ‘elastic solid’ spacetime) as it resists the compressive forces due to quantization. You are already exploring the ‘repulsive’ forces that you are attributing to dark energy (elastic solid spacetime in this view). Why not extend that ‘repulsiveness’ to dissipative gravity? Gravity only appears to be attractive due to the conservation of energy as spacetime is pulling everything apart (the physical source of entropy btw).
Another hurdle is assuming supersymmetry is between symmetric particles rather than symmetry between conservative (QCD and QED) and dissipative forces (QED, weak, and gravity). Also, the compression and perturbations of this elastic solid spacetime results in the various ‘fields’ governed by interactions with the various fundamental particles. Strong force is local due to the relative (supersymmetric) stability between conservative and dissipative forces. The weak is the amplified effect of the dissipative force of gravity relative to the strong force(?) and thus also local. Notice QED is in both and is thus the bridge, the connection between elastic spacetime and the quantized particles, the interactions within the solid/liquid colloidal mixture that is our universe.
In this view there is no need for singularities, something from nothing, any 'in between', or any of the other fantastical artifacts discussed. Straightforward. Simple. And everything in the universe can be seen as dissipative systems including us. Beautiful.
When Einstein was working on electromagnetism he didn't know or wasn't able to imagine his cosmological constant as dark energy was real. To unify electromagnetism with gravity you may think of normal gravity as the curl operator and dark energy as the divergence operator perhaps?
Just wondering, why at 3:48 do you say "He's tried for 2 years to combine electromagnetism with gravity and it didn't work"
While the caption (if, I presume , Einstein's translation) reads:
"After ceaseless searching during the past 2 years I now believe to have found the solution"
I mean, if matter is just condensed energy (whatever energy even is), and blackholes are condensed space-time? Yeah no, I've got litetally nothing.
That's absolutely the biggest one, what is energy? I mean what is it? If matter is just condensed energy, if everything is just energy, then you can't define it in terms of anything else, and you're stuck. Time to go do something else ..
Thanks, I had asked the question in comments on other physics videos, whether magnetic attraction and the attraction of positive/negative electrical charges might also have an underlying explanation involving curved spacetime, like gravity, but I had not seen an answer. It is making progress to hear that the answer is "Well, maybe", at least if I'm understanding correctly.
It seems to me (a naive layman) that if magnetic or electical attraction were "forces" and not a pseudo-force like gravity, then they would be akin to the pull of a tow truck that could pull forever, without needing to replenish a fuel source (like the tow truck needing to refill its gas tank). That would seem too much like "free energy".
As usual, a brilliant (notice how I slipped that in) presentation. I just read Einstein's Unfinished Revolution by Lee Smolin. Have you talked about Lee's idea that time is primary and space is emergent.
So if we want to describe a particle we would describe the center of the particle a 0,0,0 in a three dimensional coordinate system
Then probability of finding the particle is at x
e^-(x^p/2v) / SQRT(2*pi*v) where x is x1, x2, x3 dimension and v is the variance which is derived from uncertainty principle. And p is some factor that describes kurtosis.
The problem however when you apply general relativity is that coordinate system is a fabrication of the observer and position is relative to something else. As a consequence you are imposing a coordinate system, which quantum mechanics you can only take one measurement from. Is this distribution real or not.
So what if a particle is a black hole. R = 2 μ/c^2.
Let’s assume it’s the mass of a Top quark.
Its mass is 173 GeV/c2 or About .186 kg/.60223E24 or 0.3-E24 kg G = 66.7E-12 or 20E-36 = μ
This is then divided by 1E17 and multiplied by 2 so essentially .4E-51 which is less than a Planck length, so the distance is trivial. But to have a black hole you need a curvature of spacetime in which the gravitons evolve along two dimensions. A point has no dimensions, so that a blackhole cannot be a single graviton or anything that size or smaller because that would be dimensionless. The smallest conceivable black hole would need to have the smallest radius that might result in a blackhole negating QM is ~2.5E-35 or 2.3E-18/c^2
2.3E-18/c^2 = 2*6.67E-11*M/c^2
M= 2.3E-18/.667E-12 = 3.5E-6 kilograms or about 3.5 milligrams. Take 4mg of gold, compress it to a volume 10^93 times smaller than it is, and you can have a black hole, maybe. It would blow up and 100 feet of the surface of the earth would disappear. Blackholes take in mass, they don’t give it back. 3.5E-6kg*0.9E17 = 0.32E12 joules. (About 1/200 the yield of Little boy).
Super coold video. Thank you Sabine! It's just something so inspiring by hearing about Einsteins mistakes and dead ends too. More of these interesting failed ideas from other physicists please!
I'd like to learn more about this idea and hope others are pursuing it. I always wondered what caused Einstein to fail in getting a unified field theory. I wonder if this alternative approach which perhaps uses singularities as the fundamental pieces that make up a quantum universe might be the answer.