Einstein’s Other Theory of Everything

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Einstein completed his theory of general relativity in 1915 when he was 37 years old. What did he do for the remaining 40 years of his life? He continued developing his masterwork of course! Feeling that his theory was incomplete, Einstein pursued a unified field theory. Though he ultimately failed, the ideas he came up with were quite interesting. I have read a lot of old Einstein papers in the past weeks and here is my summary of what I believe he tried to do.
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#science #einstein #physics

[@SabineHossenfelder]

This video comes with a quiz which lets you check how much you remember: quizwithit.com/start_thequiz/1716012446752x687523319581570800

[@Thomas-gk42]

20/24 🙄😇?

[@stancartmankenny]

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?

[@derby526]

that is amazing please keep doing these quizzes on your videos

[@osmosisjones4912]

Isn't matter a form of energy and energy is space time

[@Thomas-gk42]

@@derby526 it´s a fun!

[@richardthompson6079]

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.

[@kaastue]

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.

[@GizzyDillespee]

Yeah, but it's TOO just right. It's also too just kidding...

[@piokul]

@@GizzyDillespee 😆

[@annaclarafenyo8185]

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.

[@ivoryas1696]

​@@annaclarafenyo8185 -Eh. That's your opinion. 😁-

[@MrStevos]

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]

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.

[@lanorothwolf2184]

I come for the authentic Einstein pronounciation

[@kindlin]

@@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.

[@BillAngelos]

@@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.

[@ecMathGeek]

@@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.

[@michaelpettersson4919]

Finding flaws in Einstein's theories isn't disrespectful of Einstein. Improving on his search are actually to honour him.

[@johnk9964]

There are no flaws but improvements to include cases that were not considered before, as I did. You may find below (some 8 hours ago) what I mean.

[@TheGhostGuitars]

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]

@@TheGhostGuitars Actually we have something that none has ever expected, the true unification of electromagnetism with gravity. You don't believe it? You are just a click away.

[@USMiner]

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.

[@louislesch3878]

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.

[@buddypage11]

Read my recent Medium article, and feel free to provide feedback. Ties in with your comment. "Grasping Vital Points Most Physicists Misinterpret About Reality"

[@Unmannedair]

I'll definitely check it out. Sounds interesting

[@Unmannedair]

​@@buddypage11 feedback: medium sucks.

[@buddypage11]

@@UnmannedairIt is simple and easy to use, and I am on Substack too. Just opened a long delayed Patreon yesterday.

[@nicolascalandruccio6069]

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

[@Zurpanik]

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...

[@AAjax]

She used ALGOL/C/Java/... style comment markers to start+end her rant. Just when I thought I couldn't love the channel more!

[@gamechannel1271]

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.

[@kindlin]

@@gamechannel1271 Lol, I've never even heard of ALGOL -- not that I'm some encyclopedia of programming languages or something.

[@ktrimbach5771]

ALGOL was one of the first system level computer languages. C is somewhat a derivative of that.

[@AAjax]

@@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.

[@thekaxmax]

ALGOL is still in use by physicists.

[@SB-ju4yf]

It’s so funny to listen to you - i understand nothing, but it’s like watching Spaceship Enterprise

[@robnobert]

Starship Enterprise 😉

[@Swelake]

She looks so real.

[@Swelake]

She looks so real.

[@Thomas-gk42]

Wonderful, Sabine! Exciting interesting content

[@SabineHossenfelder]

Thanks so much, really appreciate your support. (And your thoughtful comments, too!)

[@Thomas-gk42]

@@SabineHossenfelder ☺

[@alfred-vz8ti]

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.

[@daanschone1548]

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.

[@d95mback]

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]

Sorta like three space dimensions and one spacetime dimension line up with three forces and one gravity?

[@sergeynovikov9424]

only time is fundamental according to SW, while space is emergent and has not exactly 3 dimensions, but only approximately.

[@iyraspusjfzifzocyoyxyoxyoxoy]

WWAVESS 🌊🌊🌊👋👋👋💚💚💚

[@kindlin]

@@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...

[@frun]

Particles of different wavelengths feel different spacetimes, therefore SW rewriting rules.

[@ultrametric9317]

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.

[@eottoe2001]

<a href="#" class="seekto" data-time="672">11:12</a> 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!

[@nnonotnow]

Thanks for clearing that up

[@TerryBollinger]

What a wonderful video and article! Thank you, Sabine.

[@alansnyder8448]

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.

[@alexmikhylov]

I'm not fat, my spacetime is curved in a particular way

[@deltalima6703]

You have a lot of potential. But no kinetic. :D

[@afterthesmash]

I'm not plastered, my liver is a sofa cushion.

[@1fattyfatman]

Gems, all!

[@Kokuswolf]

And you attract bodies. Could be worse, right?

[@fletchergull4825]

spacetime curves in response to massive bodies bro

[@damianlegion8455]

The way you talk with your mouth nearly close is hypnotic. Amazing skill. ❤

[@thekaxmax]

Any Australian, too....

[@mikkokorhonen92]

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.

[@ianstopher9111]

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.

[@Benja.____]

Is awesome how you make a video of dense topic so light and enjoyable.

[@dreamingitself]

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

[@johnkeck]

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.

[@DrDeuteron]

if it weren't for Descartes, we'd have no idea where we're at.

[@johnkeck]

@@DrDeuteron Lol. I guess we'd be "uncoordinated"!

[@Eryktion]

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!

[@richardbrewer2937]

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.

[@MisakaMikotoDesu]

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.

[@DrDeuteron]

EE pays the bills way better.

[@Sharon-hr2]

Is there an explanation, why gravity and electromagentism follow the same law of distance, namely, decrease with the square of the distance

[@NoNameAtAll2]

3 space dimensions, constant flow from source - one dimension for distance, 2 left for area of effect flow distributes to

[@Alex-js5lg]

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.

[@SploxFox]

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.

[@IronCakeN]

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.

[@sebastiandierks7919]

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.

[@loisk6186]

I LOVE it when Sabine "rants"! 🤩 ! More ranting please! And more of these awesome general relativity/ black hole / Einstein videos... such a COOL topic,

[@PerpetualScience]

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 <a href="#" class="seekto" data-time="181">3:01</a> . I'll send you an email about it. Regarding <a href="#" class="seekto" data-time="335">5:35</a> , it could if you discard the cylindrical condition. Regarding <a href="#" class="seekto" data-time="585">9:45</a> , 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.

[@martineldritch]

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

[@LisaBlooper]

And he was right, and is still right. QM is going to turn out exactly as he would have been satisfied. Not sure why some are trying to quantise gravity. What a sloppy, gamble, wishful approach. Obviously it's the reverse.

[@altrag]

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]

Forget the equations that may suggest matter is spacetime, what does that statement or that idea even mean?

[@LisaBlooper]

@@altrag > doubtful because you cannot fathom what it could (not just what it would) look like, for qm to be understood along the lines of relativity. more specifically GR. who cares about what's doubtful to those who can't even get to the altitude which enables sight of the possibilities. see Penrose for getting started. >no theoretical basis incorrect (see 'doubtful'). not to mention, the simple fact that we can inject particles into a g field does not qualify things to "experimental basis" except in some cartoon way. it merely activates your hands into doing Something (as opposed to doing nothing). you still are without Any concept of what you are doing --- with your hands. Author cant even get the premise right "a particle in 2 places at one time". >only arg classical more intuitive there is something much more profoundly different with going in g>q direction than with going in q>g direction, than merely 'intuitive". such a shallow perspective is yours. think a little bit deeper about what the difference actually is.

[@altrag]

@@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.

[@eonasjohn]

Thank you for the video.

[@JamesMulvale]

You are doing more for science than all of science. Revolution.

[@moocow4749]

These topics, GR, QFT, and their crossover and history are so important; please keep covering them

[@blinkingmanchannel]

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 <a href="#" class="seekto" data-time="782">13:02</a> 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!❤👍👀

[@kylarirons2236]

Don’t forget Euler! More mathematics than physics, but still hugely important!

[@blairhoughton7918]

Dirac put special relativity into Schrodinger's equation and it made a smiley face.

[@JonS]

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.

[@kindlin]

@@kylarirons2236 There's basically an Euler [Something] for every field in math or physics.

[@DrDeuteron]

@@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.

[@Michael_Barrett]

Me, hearing that Einstein finished his masterwork at 37 when I haven't even started mine

[@supremelordoftheuniverse5449]

It’s too late

[@rgonnering]

This was fantastic. Sabine explained some of the topics we hear about in a way that was understandable.

[@silicon1138]

Absolutely wonderful Sabine. I watched this after having my breakfast and I will now go through my day feeling like a simple amoeba. ❤

[@vaakdemandante8772]

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.

[@user-do5fx6qg6b]

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

[@sageinit]

Kinda sounds like how chromosomes work, which feels strange

[@jefflawson7355]

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.

[@davidschroeder3272]

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.

[@romandenisov7195]

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? 🎉

[@d95mback]

They would exist in the same sense as you and I exist.

[@SabineHossenfelder]

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.

[@drbachimanchi]

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?

[@TIATAC]

👍​@@SabineHossenfelder

[@CMVMic]

​@@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.

[@timseguine2]

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.

[@frun]

This idea is being developed kzbin.info/www/bejne/oKqpp6uEZbSDfZo

[@deinauge7894]

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.

[@timseguine2]

@@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.

[@kylebowles9820]

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

[@stevelahue9918]

I don't know anything about physics but I love hearing you talk

[@DeltaVTX]

Friggin’ Einstein that guy every time I think I’ve got a good idea I find that fuzzy headed patent clerk was already there

[@blucat4]

Yeah, he stole your great idea ..

[@RetiredRhetoricalWarhorse]

It's so weird with all the English media I consume to hear someone pronounce Einstein's name correctly.

[@jeffgriffith9692]

Great subject interest content, thank you!

[@flynnparish9833]

What a breath of fresh air this channel is... after 3 hours of Terrence Howard interview, I feel like the neurons are coming back. Thank you.

[@Sidionian]

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.

[@sachinkadam2110]

I love the way Sabine speaks.

[@Oli1974]

Could be british royalty ;)

[@scene2much]

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.

[@Oli1974]

@@scene2much Nobody was saying it were bad, it only sounds a bit posh and snobbish :)

[@user-aRb00d3r]

aren't we all?..

[@blucat4]

@@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.

[@andygoldensixties4201]

History and physics masterfully combined in this video, congratulation.

[@Kronzik]

I actually love the detail and knowledge level of this video.

[@larrysiders1]

It does "feel right" that everything is some manifestation of space-time...making space/matter/energy convertable.

[@Syphirioth]

Space is not convertable. Matter and energy are within the canvas of gravity.

[@gordonwalter4293]

Sabine is great for old solid state physics guys like me. I continue to be amazed at what she makes (mostly) understandable for me.

[@Hauthorn]

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!

[@MsShirepony]

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.

[@iaindooley9275]

Gravity because gravity #qed

[@blucat4]

It's kind of a dumb way to demonstrate it, for sure.

[@Ron_Rhodes]

I'm so glad someone else has mentioned this. A disclaimer about this demonstration should always accompany it, yet I've never seen one.

[@timhaldane7588]

This is one I actually wondered, myself, until Hawking radiation showed they should disintegrate almost instantaneously.

[@lanevotapka4012]

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.

[@giorgiobarchiesi5003]

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” 😉

[@oxytocin1989]

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!

[@oxytocin1989]

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

[@paulklee5790]

This is an interesting point to hold onto… perhaps an essential one! Thank you…

[@YandiBanyu]

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)

[@inthefade]

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.

[@altrag]

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).

[@aaronjennings8385]

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.

[@SabineHossenfelder]

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.

[@DrDeuteron]

define "promising".

[@aaronjennings8385]

@@DrDeuteron that's an ai generated comment, I wouldn't know a tensor from a black hole

[@DrDeuteron]

@@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.

[@aaronjennings8385]

@DrDeuteron ai suffers from pareidolia, a chronic hallucinatory/delusions complex... it's subtle sometimes. Occasionally rather obvious

[@martingarrish4082]

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.

[@challox3840]

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.

[@AndrewBrownK]

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.

[@MrStevos]

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 ?

[@AllatumD]

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]

Basically, yes, that's what it would mean

[@blinkingmanchannel]

@@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."

[@kindlin]

@@AllatumD 99% of mass of the proton/neutron are just gluons interacting, so why not just toss in the last 1% as well?

[@MrStevos]

@@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 ?

[@pillepolle3122]

Perfect start of my day. A Coffee and hard physics.

[@luisfabricio6439]

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

[@nas8318]

Eveytime Sabine says "Einstein" I take a shot

[@dustinlange9759]

RIP

[@dominikschneeweihs9538]

I watched so many English science channels that I'm not used anymore to hear his name pronounced correctly 😅

[@kevin9218]

If that's the case, you must be really drunk by now.

[@diegoisaias5795]

That guy again?

[@nas8318]

@@kevin9218 I'm typing from the afterlife

[@dunichtich100]

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.

[@Tletna]

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 KZbin/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).

[@GK49245]

Nice topic summary. Thanks you.

[@manueljoseblancamolinos8582]

Una teoría de Todo es imposible que exista ya que de existir tendría que explicarse a sí misma ya que la propia teoría es parte del Todo.

[@pegatrisedmice]

isn't that fundamental problem of QM as well? where you get informations from a measuring device which doesn't take itself into account even though it is the sole reason we get wonky results?

[@michaellowe3665]

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.

[@MrStarchild3001]

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!!

[@unknowntexan4570]

What? No pink blouse? ❤

[@tjpprojects7192]

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.

[@blucat4]

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 ..

[@thomasfsan]

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!

[@ManuelGarcia-ww7gj]

That was one of the best seqes i have ever seen, Sabine. Cogratulations. You just sold me on Brilliant.

[@radical137]

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?

[@carlospaiva9083]

I'd like to see more videos about lesser known ideas from physicists, this is interesting

[@LQhristian]

Nice summation!!

[@hsinchiehlim2508]

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!

[@dagobertkrikelin1587]

Going back to basics is always useful for going forward.

[@JonathanLangdale]

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.

[@MichaelPiz]

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.

[@bobkoroua]

Imagine his reaction to such concepts being discussed so widely? I grasp only faintly to these questions but I understand so much more than my dad did of them. He was a much more intelligent man than me but I still remember him telling me " They don't understand gravity" We still don't but we know much more than he ever did.

[@paxdriver]

I fully appreciated the javascript notation on the rant comment btw lol perfect programming language for the context of this video, brilliant Easter egg if that was intentional

[@naasking]

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.

[@robhalstrom2937]

Thank you for your educational efforts.

[@TD39504]

Sabine, this notion that "particles are folded space" reminds me about Stephen Wolfram's attempt where he derives space-time and interactions straight out of mathematics (cellular automata).

[@MuthuKumaran-hb6ku]

Thank you...after so many years i learn this important aspect of Einstein's work, thanks to u Sabine!

[@chrismyers8274]

Thanks for reminding us of Einstein’s original intents! Great video!❤

[@latin01720]

Awesome video! Thank you.

[@bjbbshaw]

Excellent! This is why I follow Sabine!

[@paulbabypfelski6193]

❤ Strong force looks awesome with the three color graphic!

[@UpperCutZX10]

Very Nice, Sabine! I'm l doing a 'Great Courses' class on Theory of Relativity & This talk/Video (like all of your videos), is especially interesting, and provides a broader base to build an understanding of Einstein upon . .... AND ... The Brilliant Demo is very enticing, considering the course I'm currently watching is almost 20 yrs old. * So grateful for your content, &. your honest pursuit of truth & knowledge.

[@user-iz6cf7ji5k]

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.

[@Neal_Schier]

"Because it is interesting." Yes!!! It is interesting and is part of the wonderful smorgasbord of knowledge that we so very much enjoy. Time will spent. Vielen Dank Dr. Hossenfelder.

[@CitizenWill9]

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.