@@invariant47 Absolutely true, something else assuredly. No great results these past decades due to false hypotheses and bad assumptions right at the start leading to dead ends. Physicists need to thoroughly re-examine some foundations. Then they will get a broader look where the right tracks show up and realize they were walking down wrong paths at the same time.
Both failed, including susy. We need a better understanding of quantum mechanics for a unification of QM and GR. Let´s do the experiments, that SH suggests since many years.
Something else, but that something else might “borrow” or “extend” aspects from the prevailing “lines of thought” with regard to orthodoxy or non-orthodoxy. So it is probably not purely a binary answer when it comes to “this or that” is “good or bad”. Personally I said in a comment on Sabine’s channel that we needed another video as I thought that all three of videos were found wanting. So I applaud Brian for this video and what appears to be a fifth and sixth video with Carlo and Sabine to allow them to “clarify” their explanations.
People should stop being offended. If someone said your theory sucks, it's up to you either to prove it does not suck or ignore him. But being emotionally offended is not an option.
I watched it - it was great! I understand her frustration and anger - there has been no real progress since the Standard Model was completed in the 1980s (when I was still a graduate student). And what are people doing - STILL DOING? Writing nonsense bullcrap papers to get government grants. Honestly, they should go and get a REAL job! With a degree in theoretical physics (which nowadays is about as useless as a degree in Afghan Lesbian Studies or whatever the hell the Left is moaning about this week), I'm sure they could find work as a janitor or a burger-flipper. At least those are HONEST jobs!!!!!!!!!
So..Sabine is right about many things regarding her criticism, but she is also merely part of the problem when coming up with solutions. To get answers, we first need to replace the current kabal of theoretical thinkers who haven’t gotten us anywhere for 100 years. Like Einstein said; We can’t solve our problems with the same thinking we used when we created them. The essence of the issue is NOT that the fundamentals of our physical reality are necessarily difficult. The essence is that trying to combine the two mathematical sets of descriptions of it (GR and QP) turns out to be a notoriously difficult. This apparently generates even far more complex theories and math, over which we have the occasional cat fights. We are so lost in math that we don’t even recognise we are NO LONGER dealing with underlying physics anymore. As an analogy; As a kid I remembered vividly being shown a picture of a pipe with the subtitle ‘ceci n’est pas une pipe’ or in English ‘this is not a pipe’. A first rection is one of anger, because of course that’s is a pipe. Well…no, it is a flat piece of paper with a painting (pixels) on it. It doesn’t convey the same information when actually holding a physical pipe. The weight of the pipe, the feel of the material, the smell. This is EXACTLY the same problem with QP and GR. We are shown two ‘paper’ pictures of the same pipe, but this time the pipe is called ‘fundamental physics’. And what did we do for the past 100 years? We set off with scissors and glue trying ways to cut up both images and see if we can get it to fold, stick and glue them together in a different way so we get a better understanding of the object it depicts. And when the math becomes intolerable complex or even conflicting with actual physics, we even go so far as to erase physical reality (e.g. the spacetime grid as per Einstein’s 1920 Leiden lecture closing words) all together. So coming back to the pipe analogy; we are currently not only trying to stick two paper pictures on top of each other, we are now trying to merge the operating platform of a windows and an apple laptop, because we saw each of the two images of the pipe on a Mac and the other on a Windows platform. We are literally that far off in our academic heads….
@@RWin-fp5jn"We are so lost in math..." -- that´s exactly the title of Sabine´s book from 2018, so she´s not part of the problem, she already fixed that long ago, and also made a bunch of proposals to change it in her book. It seems, not many people read it. Instead, she fall under a kinda scientific inquisition in her homeland and her research wasn´t funded anymore. I personally have a lot of understanding for her anger.
Sabine just published a video and brought the dilemma of modern physics to the point. I can just repeat what I wrote in her channel: I work with a couple of highly educated, PhD. holding physicists together at Siemens. They all complain about the situation you explain here and they are all pointing to the root cause: It's about the money. People construct fancy theories to pretent progress. Why would else one give them money? It starts at the universities. Modern physics is dead and that will remain till the system gets changed.
@@fishermensfriend1224 don’t let the word “research” in “research cartels” fool you! They’re not about true research in the scientific ideal sense of furthering our understanding of Nature or contributing to reduction of uncertainties. It’s about the capture of funding and gatekeeping (both of outgroups *and* of ideas).
After watching Sabine’s last and the latest video, I feel whoever disagree with her should try to point out the flaw in her argument, if there is any. As someone who studied a bit physics during undergrad, i feel her argument is pretty clean and conclusive.
Well, string theory does physics as much as Plato did. But you need more and new experimental data that ideally is in conflict with current theories. but Sabine is also against the few big experiments that can produce them like new bigger colliders (even that I believe there will be much interesting coming out of it, we still have to check)
@@steffenbendel6031 The size of a collider that would be enough to dent the question of strings would encompass the entire solar system. It's just unfeasible. String Theory is undefeated because it's untestable.
As a Brit I would like to contribute some of my own expertise : "bollocks" are spherical objects usually seen in pairs that orbit one another in a kind of nebula-like sac that is gravitationally locked to the pillar of creation.
It's also an interesting historical fact that the observed small deviations from the spherical shape of said objects were the inspiration behind the concepts of Lorentz length contraction and Special Relativity. Not a lot of people know that.
I take it for granted that you have also observed more than once the inflation of the aforementioned pillar! This is probably where the theory of primordial inflation comes from.
I agree with her; let's stop all the crap on LQG , string theory, but also quantum gravity Sabine. Why? Well, If all the top elitist expert friends of Brian can’t even explain what gravity is or what causes it (nor the ‘quantum’ for that matter), then what is the point in trying to combine GR and QP in the first place? How exactly does that give us more insight? Trying to combine two mere math descriptions in the hope of getting to know the underlying physical truth is a fool’s errand as surely Einstein should have known (or did he?). Raised eyebrows? Ok…an analogy; If I gave you an English and Chinese version of the Torah, how does trying to combine the English and Chinese languages into ‘Chenglish’ give us more insight into the book itself? Not trying to be a drag, but I really don’t get why scientists don’t ‘question the question’ we were handed 100 years ago. It is a false one. Let me hand you a better riddle; Ever since the 1919 Solar eclipse we accepted that rest-mass (a deceptive term as there is a lot of motion inside of it) curves spacetime in a static way around heavy objects. A gravitational effect. Yet we also know there is the secondary effect of acceleration of spacetime towards the heavy object. That’s a contradiction. How can ST be both contracTED and contracTING at the same time? Moreover, unlike we are assured at high school; each effect by itself does violate energy conservation. Contracting spacetime costs energy to counter the ‘urge’ or ‘tension’ inside spacetime to go back to its original state. Next also the perpetual acceleration effect of spacetime (and any and all objects inside of it), likewise can be seen as a violation. The answer, as incredible as it seems, is that both effects are actually mutually compensating effects, much like a single complex number consists of both a real and imaginary effect. i^2 =-1 is quite literally the acceleration effect compensating the static curvature of ST. This is what our dear experts should be focussing on. So move over LQG and String Theory; it is time to correct a famous theory of Einstein if we are to understand and control gravity. Spoiler alert: it is not GR.
I'm not a physicist, but an applied mathematician, which should make my bias obvious. Remember going to lots of talks on this topic during my PhD and postdoc. Even back then, I always thought how on earth all these labs pull in funding without even having a plan for verifiable results. My personal opinion is that creating new math is like creating art. It can be beautiful and elegant, and has value. But with limited funding, I'd rather see resources being put towards more practical endeavours.
If string theory ever manages to prove the quantization of gravity they could celebrate the dropping of the unneeded "theory" by rechristening it "G-string"
As a scientist but not a physicist, I tend to lean Team Sabine. I tend to be skeptical of the claims of theoretical physicists now. I am old and have heard too many promises. By the way, could you invite Gregory Chaitain. He has make comments about academia and the progress of physics you might or might not like.
I don't understand this talk about "having a monopoly is bad". Having untestable/unfalsifiable theories is bad. Having multiple contested theories all of which ignore mathematical inconsistencies or experimental evidence is worse. Having a single theory which can be tested and proven is the most desirable outcome, and by definition that's a monopoly; or as I would call it scientific consensus.
I think his main point is that it's the main one being looked into. Having a single testable theory is important. But if it's not 100% clearly the most reliable path to explore, having everybody in the field working on and focusing on it would be bad. This is pre-scientific consensus. There isn't a consensus yet. It would be different if a theory had evidence and a ton of promise, aka the "scientific consensus." The monopoly comparison isn't supposed to extend to that. It's just to make a point.
Once we have the proven theory, there is a winner and the competition moves on to the next frontier. But while we don't have a proven theory, having a monopoly, that is one candidate that sucks in all the funding, is bad. That's what I understand here.
I appreciate the sentiment, it just doesn't make sense in this context. We cannot reach a scientific consensus if a bunk theory has a monolopoly on resources. We must remove any monopoly until a theory has proven itself fit enough to deserve said resources. At that point we may find we can move forward towards a consensus.
Sabine represents and presents sensible realism and we're very lucky to have her. It's hardly surprising a lot of supposed physicists obsessed with modern versions of Ptolemy's epicycles would rather she keep her mouth shut.
Haha, thanks for your politeness in this video Dr. Keating, that´s truly how a scientific debate should be. I´m in "team Sabine" and look forward a new episode with her in your show. All the best.
Why do you have to play a close to sub auditory repetitive tonal sound track during your talk. I do not need to be hipnotized into a somnolent state to remain engaged with the material you are presenting. Please amend your sound tack or eleminate it altogether.
I agree. Background music is a commercial video trick to impart the sensation of importance to things without actual importance. Necessary for fluff PR announcements and TV magic acts but shouldn't be necessary to talk about physics.
It may be to enable copyright strike if someone mirrors his video. He may have licensed that music. A channel mirroring him might not have the license.
I almost always find categorical statements dubious. For those who are curious, more than ten years ago (2002), Rovelli and Speziale argued that LQG does not necessarily imply violation of Lorentz invariance in the paper: Carlo Rovelli, Simone Speziale, Reconcile Planck-scale discreteness and the Lorentz-Fitzgerald contraction, Physical Review D 67, 064019 (2003) DOI: 10.1103/PhysRevD.67.064019 In short: 1. The minimum length is not a fixed property of space-time, but a minimum value of a quantum observable. This means that there is no fixed “grid” in space-time, but rather a set of possible discrete values that can be observed. 2. The eigenvalues of observables, such as area, remain unchanged under Lorentz transformations. A moving observer would see the same spectrum of discrete values, with the same minimum area. 3. What changes with the Lorentz transformation is the probability distribution of observing one of these discrete values. This means that the probability of measuring a certain area may change, but the possible measurable values remain the same.
I for one am glad there is finally some discussion on actual experimental results. Hopefully we are having similar discussions about string theory soon.
bad looping music in the background, come up with something better kiddo. dissing a diss with an empty argument filled with fancy words aint one of them.
I did watch Sabine Hossenfelder's emphatic appeal regarding whether we should continue to think of / fix linear LQG. I do have sympathy for her pragmatic approach, and the risk of unfairly distorting the balance of research investment.
There is a strong smell of personal vested interest and the sunk cost fallacy emanating from those who get their bucks and tickets to conferences from LQG.
I don't have the education to have an opinion. The debate is fascinating to follow. Evidence for Newton is anywhere you throw a baseball. Relativity plays a key role anytime I reference my car's GPS. Quantum mechanics lets me buy negative resistance devices called tunnel diodes. Is string theory in similar practical use?
what I was expecting is you checking in detail the reasons why LQG has or not has Lorenz invariance violation, instead this seems like oh someone says this someone says that and that's it. you should check their arguments and compare them. otherwise what's the point of the video?
I'm no physicist. But has some questions - let's imagine (call it gedankenexperiment) LQG is correct. What difference does it makes? QM and GE practically changed our world and Newtonian Mechanics served as one of the cornerstone of entire industrial revolution. Let's say some version of LQG is right, what difference does that make? This same question equally applies to ST. Coming out of Imagination, there are aether theories that claim to predict that same as relativity. If LQG or ST is experimentally verifiable only upto where our current theories go, then are they any differnt? I suspect the later question falls within epistemology.
What I want to know is, how willing are any of the physicists to admit it when their theories they have spent their careers on, is incorrect? At what point do we decide to put an issue such as the "everything theory" aside and apply our limited resources elsewhere?
Rovelli is riding a dead horse but he is not smart enough to see it. The problem with this type of guys is they need so many years to learn all this maths that they loose their physical inspiration, and then if they have wasted 15 years without results they can not turn easily.
I watched your original video and did not recall you saying that there were versions of loop quantum gravity that were Lorentz invariant --- especially that Rovelli & Speciale had proved (?) it was. On the contrary, your original video and that one by Hossenfelder were somehow in agreement, and in fact, it seems obvious and intuitive to a non-specialist that something of the sort should occur i.e. that the granular nature of space time induces a refractive index. It would be strange and remarkable if it did not. After looking at the abstract of the Rovelli & Speciale paper, I found it to be opaque and unconvincing. So Rovelli had better clarify this aspect. And I agree, this is an interesting development for the public. Sometimes things are published which are not correct. It happens. I've done it, admitted it. Sometimes people disagree, and a consensus should be reached. I've been in that situation too. This might be the case, regarding this issue.
I feel there was a lot of progress in astronomy/astrophysics in the last 20 years. And while quantum computing is not a new idea, it certainly makes us more familiar with understanding macroscopic superpositions.
From what I have heard as a laymen, many string theorists admit they don't think it is the 100% correct theory of our universe, even Susskind, who was at the beginning foundations of string theory says its not the theory of at least our universe, but like a intellectual/mathematical laboratory for integrating quantum mechanics and gravity.
I am on team “Truth”. You may not find it instantly, results may be misleading, but you can agree as a bunch of scientists on when something is true, agree on what you need to do, what conditions findings must fulfill, for something to be called true. I guess the above is kind of basic, should have been decided upon ages ago, but somehow I feel that, even when available, it is not taken seriously at all, because of ego, and money, you call it. I, in a practical way, did the organizational part of IT Security. The above procedure, if you like to call it that way, was fundamental to make progress, that is, to take the right measures to make sure the IT of our organization about vital infrastructure could function as undisturbed as possible: no time and efforts for shenanigans.
I'm team Hossenfelder (and Biggie FWIW though Chronic is still a great record). As a complete amateur I'd like you to ask if there are any physical experiments on the horizon that will push this debate (kicking and screaming?) into the world of physical reality. And if there are proposed experiments are there any that don't require an incredible financial investment and decades to build the apparatus.
@DrBrianKeating, in the beginning you mentioned you asked the Chinese researcher if it meant something was/was not the case. Why did you ask them and take their word for granted, instead of reviewing their paper and trying to ascertain that for yourself? Is science built upon scientists taking the word of other scientists for granted and not reviewing all of the research and data being put forth and independently trying to verify the same?
And in addition why was the name on the email from the Chinese researcher redacted if if they the lead on the paper? I get redacting the email address but the names of any and all paper authors should be named if you are going to quote them in your video. Oh, and for the record, Team Sabine all the way.
As a physics lay-person I certainly don't understand the deep esoteric physics at the levels that Sabine and that Carlo guy and other string-theorists are heatedly disagreeing about.. - But - If what you are "studying" and writing papers about, and (somehow) getting grants for isn't testable, or provable, or DISprovable then it's just not science.. it's a faith or a belief, just like religious faiths or beliefs. The adherents may BELIEVE strongly in their THINGS, but their things are not probale ortestable or falsifiable, ie.. it's not f**king science!! I just recently started hearing about this when I watched a recent video where Eric Weinstein was being interviewed by a RUclips content creator, and he discussed all of this disagreement, and talked about how Sabine was against the string-theory "belief" and I found it intriguing and have been learning all I can about this so I can understand it better. Eric Weinstein seems like a really sensible and pragmatic and decent guy, just like Sabine does, and I am one who supports their position and agrees with it.. Definitely team Sabine and Eric Weinstein when it comes to this fracas, or calumny, or kerfuffle, or whatever you want to call it. Good video - Thanks for this. You are very well spoken, and polite in this issue and explain it well.
Rovelli reached out to Hossenfelder. She reported on the argument that they had in her latest video, but then she edited her video to cut this part out.
@@Thomas-gk42 Never tell Sabine she can't do something ;-) Several people have noticed and commented on the edit. Some of us had saved the original transcript before Sabine edited the video. I had posted it on Reddit. Here is the relevant part that was mostly cut out: "Cue Carlo who says that if you quantize the angular momentum operator, then the spectrum of eigenvalues is discrete and that doesn’t violate rotational invariance, and it works similarly in Loop Quantum Gravity with Lorentz Invariance. But it doesn’t. If you calculate the expectation value of the angular momentum operator, then that will respect rotational symmetry, yes. But that’s because the eigenvalues, here comes the relevant part, take on both positive and negative values, so they can average to zero. The eigenvalues of the area operator in LQG, in contrast, are all positive valued and have a lower bound. Consequently, the expectation value for the area in loop quantum gravity is bounded from below. It can’t transform under the Lorentz-group. Mathematical fact. Of course Carlo knows this. Everyone who works on this stuff know this. They just repeat this angular momentum story because it sounds superficially plausible if you don’t know anything about quantum physics. Now you can say, alright, the area can’t transform under Lorentz-transformations. So maybe there’s some quantum stuff going on and weird things happen. Yeah, actually Carlo and Simone said that in their paper. And that’s also why some people in loop quantum gravity said there ought to be deviations from Lorentz invariance. I tried to tell them long ago that this can’t work because these deviations would inevitably be so large we’d have seen them already. They didn’t want to hear that. There are still people writing papers about this nonsense."
@@pokerandphilosophy8328 You´re right, I´m member of the channel and have earlier access to the videos, and she cutted indeed some technical details (I remember the thing with the negative and positive eigenvalues). Perhaps it´s possible, before the vid is published? In earlier videos, in which she noticed failures, she took off the whole thing and uploaded it completely new. Not sure, why she cutted some parts, cause the criticism about Rovelli is still in. Maybe, she thought, that the vid is technically to difficult for most of her audience, which would be unecessary for her message.
@@Thomas-gk42 I'm subscribed but I'm not a member. I think the edit came at least one day after the video was widely released. One viewer had made the following comment: "For a theory to have Lorentz invariance doesn’t mean expectation value of the operators must be zero. Having Lorentz invariance just means the theory transforms (in some well defined way) under Lorentz transformations. Take a single particle State in quantum field theory. The momentum isn’t invariant under Lorentz transformations. And it’s expectation value isn’t zero. It transforms under the Wigner little group transformation. I actually think Rovelli has a point. You can write down your states in terms of observables which aren’t Lorentz invariant, so long as the transformation properties on the states transform under some well defined transformations under Lorentz transformations." Sabine also had three blog posts where the issue the Lorentz invariance in LQG was broached upon.
### Catchphrase "Feel the Pull: Think Gravity." ### Super-Liminal Influencing Campaign A super-liminal campaign might involve delivering the message in an unusually direct and intense manner, like exaggerated enthusiasm or unexpected interruptions. But instead of screaming, imagine a deep, resonant voice saying, *“What’s holding you down? Explore gravity’s invisible power!”* on every channel at a heightened volume, but not quite shouting. You want to create intrigue and curiosity without overwhelming or turning people away!
DONT APOLOGIZE!! That Witten thumbnail was the most hilarious thing I’ve seen in a while 😂 Will be stealing from you ✌️ In all seriousness, if the physicists the thumbnail is making fun of are so humorless or uptight that a meme offended them, then it just proves the lack of confidence these scientists have in their own work. If anything, it goes to show that Sabine’s concerns are totally right, in that these people are just churning out mathematical word salad that doesn’t really further our understanding of Nature or reduce our uncertainty regarding current problems. It *would* be the case they’re just taking (mostly)tax payer money to play this stupid game modern scientists play where it’s more about showing off to your peers than actually solving problems.
Causal set theory also violates Lorentz invariance, but at high energy scales close to the Planck scale. Untestable. As for your earlier video Brian, the cited experiment was not necessarily applicable to LQG, given the scales. There are plenty of theories and models that have arguably untestable features, including inflation and prior epochs.
Yooooo😮Thats heated. I think gravity is a wave. Space acting like it’s own substance creates a gradient. Like a liquid shadow wall space constantly caves around our earth, and other masses. Not to mention, but when you’re attacked to an object at velocity all you know is that speed. Any movements off the mass must be extra energy to escape it. I know you guys know that, but think about it? We are traveling at 70,000 MPH around the sun. That will stick you to an object just because of the matching velocities.
"Brain is is this true, as I am told, that you put a video out..." I love that it implies he didn't even watch it. He just said that someone else did and told him.
I have watched a few of your videos before. This time you earned a subscriber in me for your balanced view about this sociology of physics controversy as you rightly call it.
I like this drama, I may not be smart enough to have scientific opinions yet but i prefer it over celebrity drama that doesn't teach or help us progress.
Please have Carlo alone specify in layman’s terms how the criticism from 2004 is debunked. Which LQG models do predict LIV (if any, and why) and which do not (and how and why). This point is crucial. 🤓
Baez cut the knots and dropped the loops and Greene just went Greye. Meanwhile, just like that Epic Rap Battle video between McDonalds and Burger King, neither side won, because Wendy crashed the scene at the last minute. So, Oppenheim is Wendy.
I'm not a physicist but computer scientist. To me, patterns are everything. If code produces no tangible results yet consumes more and more resources, it's a defect. As it appears, the only reason the pattern hasn't crashed the 'system' is because more and more resources are thrown at the system. It's not meaningless to develop new tools and understanding. It looks more like small 's' science with big 'S' aspirations.
At the end of the day, if it doesn't allow a test, it isn't science, and if it does allow a test and that test rules it out, it is science but wrong. It does feel a bit like physics has lost sight of this.
Loop Quantum Gravity is a beautiful theory and in my opinion is closer to the truth than anything anyone else has put forth. What is your theory Sabine? You don’t have one? You just seem to tear everyone’s else’s ideas down but have none of your own. Loop Quantum Gravity and another theory called Emergent Gravity are both going down the right road. String theory is nonsense I agree with Sabine on that but don’t agree on much else with her. Carlo Rovelli is a brilliant physicist. One of the best of the last 25 years.
The best science occurs when you have deeply divisive opinions, yet when all sides have the core concept of accepting the possibility of being wrong. I dunno, but if it came to a cage match , my money would be on Sabine. LOL Just remember Tupac spelled backwards is still Caput ! 😊
Any theory of quantum gravity can only be tested in the domain of particle physics, because they are untestable in the domain of gravity and space-time. However, both string theory and loop quantum gravity are untestable in the domain of particle physics as well. So you need another approach. For example, the strand tangle model.
BRIAN, here's an experimental physicist, one who follows what the experiment dictates. WITH all respect, you are fooling yourself. YOU should pay attention to what SABINE is explaining than to follow your ego. Simply apologize in public with her, and we will see courage developing in you. Best for you, good luck, and take care of the taxpayers who support you.
LQG just seems to be correct. Sort of like General Relativity it just seems right. Sabine Hossenfelder is such a pessimistic annoying person. I can’t see how ANYONE in their right mind would work with her! It’s almost like she gets off on tearing others work down. Come up with a theory of your own Sabine! You can’t do it right?
Your line of thinking about gravity being linked to universal motion and possibly emerging from the dynamic nature of the cosmos is intriguing and resonates with several existing frameworks, but it doesn’t neatly fit into just one named theory or school of thought. However, there are some areas of physics and cosmology that explore ideas related to this concept. Here’s an overview of some relevant frameworks that might be connected to your thoughts: ### 1. **Mach’s Principle** Mach’s Principle suggests that local physical laws are influenced by the large-scale structure of the universe. In essence, the inertia of an object is somehow related to the distribution of mass and energy throughout the entire universe. While this doesn’t directly address gravity emerging from motion, it aligns with your thinking that local phenomena like gravity could be influenced by the global structure of the universe and its state of motion. - **Relevance**: Your idea that motion and gravitational forces are interconnected on a cosmic scale has similarities with Mach’s Principle, which implies that local motion could be tied to the universe’s large-scale motion. ### 2. **Emergent Gravity and Holographic Principle** Physicist Erik Verlinde proposed a theory known as *emergent gravity*, which suggests that gravity might not be a fundamental force but rather an emergent phenomenon arising from the underlying microscopic building blocks of space-time, similar to how temperature emerges from the motion of particles. - **Relevance**: Your speculation that gravity could be related to “emerging from motion” and that it might not be a “standalone” force parallels the idea that gravity could be an emergent property tied to deeper structures of space-time. ### 3. **Dynamic Space-Time and Gravity** There are various theories in cosmology that explore the relationship between space-time dynamics and gravity, such as *quantum gravity* theories and *string theory*. These frameworks try to understand gravity as a manifestation of space-time geometry influenced by quantum fields or strings. - **Relevance**: When you discuss “motion creating gravity” and “the fabric of existence,” these ideas have echoes in quantum gravity research, where gravity emerges from deeper geometric or quantum structures of space-time. ### 4. **Shape Dynamics** Shape Dynamics is an alternative to General Relativity, where gravity is understood through the evolution of spatial conformal geometry. Instead of focusing solely on the curvature of space-time, it looks at the shape and motion of spatial configurations. - **Relevance**: This theory considers the evolution of spatial configurations over time and could offer a new perspective on how gravity and motion are intertwined. ### 5. **Cosmological Constant and Dark Energy** Your idea that gravity could be tied to a universal expansion, where everything is constantly “falling” or moving outward, could be connected to concepts involving dark energy and the cosmological constant. The accelerated expansion of the universe suggests there’s a repulsive force (often attributed to dark energy) counteracting gravity on large scales. - **Relevance**: If gravity is linked to the universe’s expansion and motion, exploring how dark energy and gravity interact could be relevant, especially when looking at gravity’s role on the largest scales. ### Summary There isn’t a single named theory that completely captures your line of thinking, but it seems to align most closely with ideas from *emergent gravity*, *Mach’s Principle*, and certain interpretations of *quantum gravity*. These theories attempt to describe gravity not as a primary force but as something arising from deeper, more fundamental dynamics, whether through motion, information, or energy distributions in space-time. While this isn’t a comprehensive list of related theories, it should provide some starting points for further exploration and alignment of your thoughts with ongoing discussions in theoretical physics. If you’re interested in delving deeper, exploring Mach’s Principle and emergent gravity frameworks could be particularly rewarding.
While I was in undergrad and hanging out with a friend of mine that was in the physics program (I’m a biologist), I joked to her that at the level of abstraction that current theoretical physicists were operating, a theoretical physicist is one stupid assumption away from becoming pure mathematicians. This “joke” isn’t funny anymore. At this point, publishers should demand a comprehensive list of mathematical and physical assumptions being employed for the theory developed in a manuscript, regardless of how trivial. A policy where theorists are given a SMALL budget of unverified assumptions should be employed. For example, your models should be based on wholly established physics, data or results from the experimental literature, and ONE “free” assumption. Then see how high that rocket can fly. One freebie seems harsh, but thinking about this stupid idea a little more, I realized that such a harsh constraint might actually make theorists think harder or more creatively. Nothing forces out of the box thinking like restraints that have to be overcome. “We haven’t the money, so we have to think!”
We need to consider that there may be an infinite number of disparate models that all test right, because our ability to verify is bound by our understanding of the universe. It's a paradox : We need the models to design the observations, yet we need observations that are not informed by the model. This means that we may well only be able to make discoveries - i.e. verify our hypotheses or simply stumble upon them, by chance.
Hi, I just wanted to say I appreciate your position on not trying to offend other experts and be charitable towards them. This reminds me of Leibniz's saying that you "shouldn't offend accepted sentiments", phrase which has been very much criticized, but that other philosophers like Isabelle Stengers (a conational of mine and a friend of late Bruno Latour, since you mention sociology of science) reactivate today, by saying that either in science or in politics, the goal is not to crush an opponent but to compose a common world, and for this you have no choice but to live with the other and have to find a way to express what you mean and what's important to you without trying to destroy others' views, because that closes the space for relationality and change instead of opening it. And in this time of strong polarization, seeing someone who simply shows he has respect for the people he talks about and is not there to offend them, is very appreciated. Looking forward to more videos !
It made sense to develop the model of loop quantum gravity. You wanted to see how a discrete space would behave in reality. It predicted that light speed should differ based on wavelength. This was falsified! Now, there is no reason to add non linear terms to loop quantum gravity. Why would you do that? The question is, what does the new theory test? What are the additional terms for? If you create a discrete space and then use error correction, you are no longer in a discrete space. I am by no means a loop quantum gravity expert. I have no idea how the exact theory works. All I know is that they divide space in triangles and that the area of triangles has a specific meaning. And that's it. The scientists need to convince us. That's their job. And so far I haven't seen a convincing reason to continue research into loop quantum gravity.
IMHO physics has a fundamental problem due to the fact that physicists are willing to label (or consider) some theories "laws". The problem arises from the fact that the term "law" places artificial boundaries on the subject matter that causes anomalies to be (basically) ignored. A good example of this is equating over-unity with perpetual motion. If a claim of over-unity is made it can immediately be shot down by stating that over-unity allows for perpetual motion and the second "law" of thermodynamics tells us that is an impossibility. The truth is over-unity in a closed system is quite easy to achieve but will not allow for perpetual motion as they are two totally different processes. The interaction of two or more magnetic fields is an active physical force which constitutes work. Suppose we have two beams situated parallel to one and other, each with a pivot at its center point. If we attach a magnet to one end of each beam so the magnets are repelling each other this will cause the other ends of the beams to be forced together in a pinching motion. A modern neodymium magnet has a theoretical lifespan of approximately 1000 years and considering that a 2 inch Nd cube is capable of almost 500 lbs. of physical force it has an energy density equaled only by a nuclear reaction. Now suppose we place a scale between the pinching end of those beams to measure the ACTIVE force created by the interaction of those two IMF's (Independent Magnetic Fields, magnets). At over 800 lbs. of active force this small device will very quickly "pay off" its energy deficit and then continue to output an active force (as shown on the scale) for hundreds of years. This is not only over-unity in a "closed system", it is over-unity on a massive scale, yet it doesn't automatically allow for perpetual motion. My point being, we shouldn't limit knowledge by placing artificial boundaries (laws) within which all scientific research must be conducted.
I don’t understand why names that are in pubic papers need to be redacted. I also don’t understand why the names of those who have come on the channel, and therefore publicly made statements, need to be unsaid:.
Discussion must continue as no one is declaring a final solution to the origin of Gravity. In a recent post Sabina showed that the understanding of Loop Quantum Gravity has nodally connected strings. This cannot be the reality as such a structure would leak energy across Field causing an eventual uniform energy level. The Field String Loops must be isolated to preserve the Gravitational Field Intensity Gradient.
Dude, if you personally know Carlos Rovelli and consider Lee Smolin a mentor and had him on your podcast… f’ing email them before making a video debunking their life’s work… it’s not rocket science doc.
It looked like gangsters/mobsters beating the sht out of someone but when they looked up close it was the universe, galaxy, sun, moon, and loop quantum gravity from the future beating up string theorists. They said "don't ever describe us" lol jk.
If you want science to be pure and intellectually honest - you need to pull the financial incentive out of the scientific endeavor. Period. Even then you're dealing with ego issues (which, honestly, would be much easier to deal with if monetary incentives weren't there to bolster beliefs about one's own scientific endeavors) ... but still. First step is nixing the financial incentive, second step is teaching everybody how to self-check their own ego.
When did scientists become such drama queens? Grow some and admit failures, even when you tried for years...even Elvis stopped trying acting after a decade and got back to performing music.
Brian struggling to justify LQG. Why are you sacred of Carlo. What's wrong be string monopoly if string theory can bring every field of physics even conciseness. Meanwhile loop quantam gravity can't even try to solve Information paradox.
![What Is The Higgs Field? Matt Strassler [Ep. 460]](/img/1.gif)
What is the best candidate for a Theory of Quantum Gravity: String Theory or Loop Quantum Gravity? Or something else?
something else
theoretical physics is in the dark ages of null results
@@invariant47 Absolutely true, something else assuredly. No great results these past decades due to false hypotheses and bad assumptions right at the start leading to dead ends. Physicists need to thoroughly re-examine some foundations. Then they will get a broader look where the right tracks show up and realize they were walking down wrong paths at the same time.
Both failed, including susy. We need a better understanding of quantum mechanics for a unification of QM and GR. Let´s do the experiments, that SH suggests since many years.
Something else, but that something else might “borrow” or “extend” aspects from the prevailing “lines of thought” with regard to orthodoxy or non-orthodoxy. So it is probably not purely a binary answer when it comes to “this or that” is “good or bad”.
Personally I said in a comment on Sabine’s channel that we needed another video as I thought that all three of videos were found wanting. So I applaud Brian for this video and what appears to be a fifth and sixth video with Carlo and Sabine to allow them to “clarify” their explanations.
People should stop being offended. If someone said your theory sucks, it's up to you either to prove it does not suck or ignore him. But being emotionally offended is not an option.
It is HOW THEY SAY IT!
The investment bias is one of the hard problems in science. Maybe we need a psycologist.
Who knows Rovelli isn't surprised he is offended. His political views are very much in line with an authoritarian mindset.
philosophy is dead in physics that's why physics has these problems
@@williamblake7386
Right! Lay out the facts/arguments and let the best explanation win.
Sabine just dropped a blistering diss track
I watched it - it was great! I understand her frustration and anger - there has been no real progress since the Standard Model was completed in the 1980s (when I was still a graduate student). And what are people doing - STILL DOING? Writing nonsense bullcrap papers to get government grants. Honestly, they should go and get a REAL job! With a degree in theoretical physics (which nowadays is about as useless as a degree in Afghan Lesbian Studies or whatever the hell the Left is moaning about this week), I'm sure they could find work as a janitor or a burger-flipper. At least those are HONEST jobs!!!!!!!!!
@@DarthQuantum-ez8qz They do not have to flip burgers. They are perfectly qualified to teach High School Algebra or something.
@@DarthQuantum-ez8qz 💯
So..Sabine is right about many things regarding her criticism, but she is also merely part of the problem when coming up with solutions. To get answers, we first need to replace the current kabal of theoretical thinkers who haven’t gotten us anywhere for 100 years. Like Einstein said; We can’t solve our problems with the same thinking we used when we created them.
The essence of the issue is NOT that the fundamentals of our physical reality are necessarily difficult. The essence is that trying to combine the two mathematical sets of descriptions of it (GR and QP) turns out to be a notoriously difficult. This apparently generates even far more complex theories and math, over which we have the occasional cat fights. We are so lost in math that we don’t even recognise we are NO LONGER dealing with underlying physics anymore. As an analogy; As a kid I remembered vividly being shown a picture of a pipe with the subtitle ‘ceci n’est pas une pipe’ or in English ‘this is not a pipe’. A first rection is one of anger, because of course that’s is a pipe. Well…no, it is a flat piece of paper with a painting (pixels) on it. It doesn’t convey the same information when actually holding a physical pipe. The weight of the pipe, the feel of the material, the smell. This is EXACTLY the same problem with QP and GR. We are shown two ‘paper’ pictures of the same pipe, but this time the pipe is called ‘fundamental physics’. And what did we do for the past 100 years? We set off with scissors and glue trying ways to cut up both images and see if we can get it to fold, stick and glue them together in a different way so we get a better understanding of the object it depicts. And when the math becomes intolerable complex or even conflicting with actual physics, we even go so far as to erase physical reality (e.g. the spacetime grid as per Einstein’s 1920 Leiden lecture closing words) all together. So coming back to the pipe analogy; we are currently not only trying to stick two paper pictures on top of each other, we are now trying to merge the operating platform of a windows and an apple laptop, because we saw each of the two images of the pipe on a Mac and the other on a Windows platform. We are literally that far off in our academic heads….
@@RWin-fp5jn"We are so lost in math..." -- that´s exactly the title of Sabine´s book from 2018, so she´s not part of the problem, she already fixed that long ago, and also made a bunch of proposals to change it in her book. It seems, not many people read it. Instead, she fall under a kinda scientific inquisition in her homeland and her research wasn´t funded anymore. I personally have a lot of understanding for her anger.
Sabine just published a video and brought the dilemma of modern physics to the point. I can just repeat what I wrote in her channel: I work with a couple of highly educated, PhD. holding physicists together at Siemens. They all complain about the situation you explain here and they are all pointing to the root cause: It's about the money. People construct fancy theories to pretent progress. Why would else one give them money? It starts at the universities. Modern physics is dead and that will remain till the system gets changed.
On the money. Academia is basically a consortium of research cartels.
@@haldanesghost I can life with that, if it's about research. But here basically it's about fake pretending to be research.
@@fishermensfriend1224 don’t let the word “research” in “research cartels” fool you! They’re not about true research in the scientific ideal sense of furthering our understanding of Nature or contributing to reduction of uncertainties. It’s about the capture of funding and gatekeeping (both of outgroups *and* of ideas).
Well, last time physicists made the real progress we got nukes. Maybe let's hold them a while so they don't make blackholes here? :)
After watching Sabine’s last and the latest video, I feel whoever disagree with her should try to point out the flaw in her argument, if there is any. As someone who studied a bit physics during undergrad, i feel her argument is pretty clean and conclusive.
Perfect.
You rock
Well, string theory does physics as much as Plato did. But you need more and new experimental data that ideally is in conflict with current theories. but Sabine is also against the few big experiments that can produce them like new bigger colliders (even that I believe there will be much interesting coming out of it, we still have to check)
@@steffenbendel6031 The size of a collider that would be enough to dent the question of strings would encompass the entire solar system. It's just unfeasible. String Theory is undefeated because it's untestable.
👍
Sabine just put out a video about this, lol. Pretty much owns everyone.
As a Brit I would like to contribute some of my own expertise : "bollocks" are spherical objects usually seen in pairs that orbit one another in a kind of nebula-like sac that is gravitationally locked to the pillar of creation.
It's also an interesting historical fact that the observed small deviations from the spherical shape of said objects were the inspiration behind the concepts of Lorentz length contraction and Special Relativity. Not a lot of people know that.
@@robertbrown1778 It's funny how sensitive astro physicians who are into strings are about length contraction and speed.
I take it for granted that you have also observed more than once the inflation of the aforementioned pillar! This is probably where the theory of primordial inflation comes from.
This inflation happens, appropriately, when there is a big bang
Bon Scott, when recording with AC/DC, had the most relevant take on this subject.
Sabine just summed it up nicely, "sick of hearing it."
She also used some much stronger language. 🤬
I agree with her; let's stop all the crap on LQG , string theory, but also quantum gravity Sabine. Why? Well, If all the top elitist expert friends of Brian can’t even explain what gravity is or what causes it (nor the ‘quantum’ for that matter), then what is the point in trying to combine GR and QP in the first place? How exactly does that give us more insight? Trying to combine two mere math descriptions in the hope of getting to know the underlying physical truth is a fool’s errand as surely Einstein should have known (or did he?). Raised eyebrows? Ok…an analogy; If I gave you an English and Chinese version of the Torah, how does trying to combine the English and Chinese languages into ‘Chenglish’ give us more insight into the book itself? Not trying to be a drag, but I really don’t get why scientists don’t ‘question the question’ we were handed 100 years ago. It is a false one. Let me hand you a better riddle;
Ever since the 1919 Solar eclipse we accepted that rest-mass (a deceptive term as there is a lot of motion inside of it) curves spacetime in a static way around heavy objects. A gravitational effect. Yet we also know there is the secondary effect of acceleration of spacetime towards the heavy object. That’s a contradiction. How can ST be both contracTED and contracTING at the same time? Moreover, unlike we are assured at high school; each effect by itself does violate energy conservation. Contracting spacetime costs energy to counter the ‘urge’ or ‘tension’ inside spacetime to go back to its original state. Next also the perpetual acceleration effect of spacetime (and any and all objects inside of it), likewise can be seen as a violation. The answer, as incredible as it seems, is that both effects are actually mutually compensating effects, much like a single complex number consists of both a real and imaginary effect. i^2 =-1 is quite literally the acceleration effect compensating the static curvature of ST. This is what our dear experts should be focussing on. So move over LQG and String Theory; it is time to correct a famous theory of Einstein if we are to understand and control gravity. Spoiler alert: it is not GR.
@@Mentaculus42 I backed up and replayed that bit 5 times. Good start to the day.
With a couple of choice words to garnish it, which had me literally laughing out loud.
She certainly did
why the background music.....it's incredibly annoying and distracting
😂😂
I'm not a physicist, but an applied mathematician, which should make my bias obvious. Remember going to lots of talks on this topic during my PhD and postdoc. Even back then, I always thought how on earth all these labs pull in funding without even having a plan for verifiable results. My personal opinion is that creating new math is like creating art. It can be beautiful and elegant, and has value. But with limited funding, I'd rather see resources being put towards more practical endeavours.
Awesome :)
'My personal opinion is that creating new math is like creating art.' ...a very cogent take.
I'm with Sabine
Me too
@@AC-qh2ei carlo said that she is a little witch.
@@maus3454 and me.
🙏🙏👌👌😎😎
Same.
I have a theory it is called "gravity loop quantum string field" to satisfy both parties.
you forgot the susy-gang😉
@@Thomas-gk42 ha ha
Did u ensure that it is not falsifiable?
If string theory ever manages to prove the quantization of gravity they could celebrate the dropping of the unneeded "theory" by rechristening it "G-string"
🤣🤣🤣🤣🤣🤣👌👌❤❤
As a scientist but not a physicist, I tend to lean Team Sabine. I tend to be skeptical of the claims of theoretical physicists now. I am old and have heard too many promises. By the way, could you invite Gregory Chaitain. He has make comments about academia and the progress of physics you might or might not like.
I don't understand this talk about "having a monopoly is bad". Having untestable/unfalsifiable theories is bad. Having multiple contested theories all of which ignore mathematical inconsistencies or experimental evidence is worse. Having a single theory which can be tested and proven is the most desirable outcome, and by definition that's a monopoly; or as I would call it scientific consensus.
I think his main point is that it's the main one being looked into. Having a single testable theory is important. But if it's not 100% clearly the most reliable path to explore, having everybody in the field working on and focusing on it would be bad. This is pre-scientific consensus. There isn't a consensus yet. It would be different if a theory had evidence and a ton of promise, aka the "scientific consensus." The monopoly comparison isn't supposed to extend to that. It's just to make a point.
Maybe we should just put string theory into the math department or maybe to frighten the philosophers.
Once we have the proven theory, there is a winner and the competition moves on to the next frontier. But while we don't have a proven theory, having a monopoly, that is one candidate that sucks in all the funding, is bad. That's what I understand here.
I appreciate the sentiment, it just doesn't make sense in this context. We cannot reach a scientific consensus if a bunk theory has a monolopoly on resources. We must remove any monopoly until a theory has proven itself fit enough to deserve said resources. At that point we may find we can move forward towards a consensus.
Team Sabine.
Sabine represents and presents sensible realism and we're very lucky to have her. It's hardly surprising a lot of supposed physicists obsessed with modern versions of Ptolemy's epicycles would rather she keep her mouth shut.
Haha, thanks for your politeness in this video Dr. Keating, that´s truly how a scientific debate should be. I´m in "team Sabine" and look forward a new episode with her in your show. All the best.
Yes Brian did a good job, Sabine also had a lot of 🤬 to say, maybe kinda …
Why do you have to play a close to sub auditory repetitive tonal sound track during your talk. I do not need to be hipnotized into a somnolent state to remain engaged with the material you are presenting. Please amend your sound tack or eleminate it altogether.
Hummm does he work for you , don’t think so
Lmao
I agree. Background music is a commercial video trick to impart the sensation of importance to things without actual importance.
Necessary for fluff PR announcements and TV magic acts but shouldn't be necessary to talk about physics.
It may be to enable copyright strike if someone mirrors his video. He may have licensed that music. A channel mirroring him might not have the license.
The use of this manipulation is spreading on RUclips.
Team Sabine all the way
I almost always find categorical statements dubious. For those who are curious, more than ten years ago (2002), Rovelli and Speziale argued that LQG does not necessarily imply violation of Lorentz invariance in the paper:
Carlo Rovelli, Simone Speziale, Reconcile Planck-scale discreteness and the Lorentz-Fitzgerald contraction, Physical Review D 67, 064019 (2003) DOI: 10.1103/PhysRevD.67.064019
In short:
1. The minimum length is not a fixed property of space-time, but a minimum value of a quantum observable. This means that there is no fixed “grid” in space-time, but rather a set of possible discrete values that can be observed.
2. The eigenvalues of observables, such as area, remain unchanged under Lorentz transformations. A moving observer would see the same spectrum of discrete values, with the same minimum area.
3. What changes with the Lorentz transformation is the probability distribution of observing one of these discrete values. This means that the probability of measuring a certain area may change, but the possible measurable values remain the same.
I for one am glad there is finally some discussion on actual experimental results. Hopefully we are having similar discussions about string theory soon.
bad looping music in the background, come up with something better kiddo. dissing a diss with an empty argument filled with fancy words aint one of them.
I did watch Sabine Hossenfelder's emphatic appeal regarding whether we should continue to think of / fix linear LQG. I do have sympathy for her pragmatic approach, and the risk of unfairly distorting the balance of research investment.
There is a strong smell of personal vested interest and the sunk cost fallacy emanating from those who get their bucks and tickets to conferences from LQG.
Yes. Please bring more scientific debate to the public forum.
I don't have the education to have an opinion. The debate is fascinating to follow.
Evidence for Newton is anywhere you throw a baseball. Relativity plays a key role anytime I reference my car's GPS. Quantum mechanics lets me buy negative resistance devices called tunnel diodes.
Is string theory in similar practical use?
Came here from Sabine's video. You should all go to the APS Global Summit next year and duke it out.
what I was expecting is you checking in detail the reasons why LQG has or not has Lorenz invariance violation, instead this seems like oh someone says this someone says that and that's it. you should check their arguments and compare them. otherwise what's the point of the video?
Sabine has rightfully brought attention to the futility of those clinging on to unproven theories that are long shown to be wrong.
Im on the Sabine Brian Team🎉
Theoretical physicists seem determined to prove that professions can have balance of payments crises too.
Galileo's model was quite different than Copernicus and quite wrong. Kepler is the guy that designed our current models.
I'm no physicist. But has some questions - let's imagine (call it gedankenexperiment) LQG is correct. What difference does it makes? QM and GE practically changed our world and Newtonian Mechanics served as one of the cornerstone of entire industrial revolution. Let's say some version of LQG is right, what difference does that make? This same question equally applies to ST. Coming out of Imagination, there are aether theories that claim to predict that same as relativity. If LQG or ST is experimentally verifiable only upto where our current theories go, then are they any differnt? I suspect the later question falls within epistemology.
Part of the issue is stating, "Which side are you on?" Entrenched positions are the biggest problem with modern physics.
Sabine makes sense.
But she has no way forward.
What I want to know is, how willing are any of the physicists to admit it when their theories they have spent their careers on, is incorrect? At what point do we decide to put an issue such as the "everything theory" aside and apply our limited resources elsewhere?
The best theory is something which can be proofed by measuring it. Not just something that seems to be hidden in mathematics/your fantasy.
Rovelli is riding a dead horse but he is not smart enough to see it. The problem with this type of guys is they need so many years to learn all this maths that they loose their physical inspiration, and then if they have wasted 15 years without results they can not turn easily.
I watched your original video and did not recall you saying that there were versions of loop quantum gravity that were Lorentz invariant --- especially that Rovelli & Speciale had proved (?) it was. On the contrary, your original video and that one by Hossenfelder were somehow in agreement, and in fact, it seems obvious and intuitive to a non-specialist that something of the sort should occur i.e. that the granular nature of space time induces a refractive index. It would be strange and remarkable if it did not. After looking at the abstract of the Rovelli & Speciale paper, I found it to be opaque and unconvincing. So Rovelli had better clarify this aspect. And I agree, this is an interesting development for the public. Sometimes things are published which are not correct. It happens. I've done it, admitted it. Sometimes people disagree, and a consensus should be reached. I've been in that situation too. This might be the case, regarding this issue.
One reason physics is dead is that we may be at the edge of our testing (proving) or understanding. We can't, in principle, know everything.
I feel there was a lot of progress in astronomy/astrophysics in the last 20 years. And while quantum computing is not a new idea, it certainly makes us more familiar with understanding macroscopic superpositions.
From what I have heard as a laymen, many string theorists admit they don't think it is the 100% correct theory of our universe, even Susskind, who was at the beginning foundations of string theory says its not the theory of at least our universe, but like a intellectual/mathematical laboratory for integrating quantum mechanics and gravity.
I am on team “Truth”. You may not find it instantly, results may be misleading, but you can agree as a bunch of scientists on when something is true, agree on what you need to do, what conditions findings must fulfill, for something to be called true.
I guess the above is kind of basic, should have been decided upon ages ago, but somehow I feel that, even when available, it is not taken seriously at all, because of ego, and money, you call it.
I, in a practical way, did the organizational part of IT Security. The above procedure, if you like to call it that way, was fundamental to make progress, that is, to take the right measures to make sure the IT of our organization about vital infrastructure could function as undisturbed as possible: no time and efforts for shenanigans.
I'm team Hossenfelder (and Biggie FWIW though Chronic is still a great record). As a complete amateur I'd like you to ask if there are any physical experiments on the horizon that will push this debate (kicking and screaming?) into the world of physical reality. And if there are proposed experiments are there any that don't require an incredible financial investment and decades to build the apparatus.
that ed witten meme was epic 😂
...and no reason to be insulted.
Well, I know what my new desktop image is gonna be...Ed Whitten o.g. !
@DrBrianKeating, in the beginning you mentioned you asked the Chinese researcher if it meant something was/was not the case. Why did you ask them and take their word for granted, instead of reviewing their paper and trying to ascertain that for yourself? Is science built upon scientists taking the word of other scientists for granted and not reviewing all of the research and data being put forth and independently trying to verify the same?
And in addition why was the name on the email from the Chinese researcher redacted if if they the lead on the paper? I get redacting the email address but the names of any and all paper authors should be named if you are going to quote them in your video.
Oh, and for the record, Team Sabine all the way.
As a physics lay-person I certainly don't understand the deep esoteric physics at the levels that Sabine and that Carlo guy and other string-theorists are heatedly disagreeing about..
- But - If what you are "studying" and writing papers about, and (somehow) getting grants for isn't testable, or provable, or DISprovable then it's just not science.. it's a faith or a belief, just like religious faiths or beliefs. The adherents may BELIEVE strongly in their THINGS, but their things are not probale ortestable or falsifiable, ie.. it's not f**king science!!
I just recently started hearing about this when I watched a recent video where Eric Weinstein was being interviewed by a RUclips content creator, and he discussed all of this disagreement, and talked about how Sabine was against the string-theory "belief" and I found it intriguing and have been learning all I can about this so I can understand it better. Eric Weinstein seems like a really sensible and pragmatic and decent guy, just like Sabine does, and I am one who supports their position and agrees with it..
Definitely team Sabine and Eric Weinstein when it comes to this fracas, or calumny, or kerfuffle, or whatever you want to call it.
Good video - Thanks for this. You are very well spoken, and polite in this issue and explain it well.
I was very disappointment to not see Rovelli & Hossenfelder speaking to each other.
Rovelli reached out to Hossenfelder. She reported on the argument that they had in her latest video, but then she edited her video to cut this part out.
@@pokerandphilosophy8328 It´s impossible for creators to cut parts out of the videos.
@@Thomas-gk42 Never tell Sabine she can't do something ;-) Several people have noticed and commented on the edit. Some of us had saved the original transcript before Sabine edited the video. I had posted it on Reddit. Here is the relevant part that was mostly cut out: "Cue Carlo who says that if you quantize the angular momentum operator, then the spectrum of eigenvalues is discrete and that doesn’t violate rotational invariance, and it works similarly in Loop Quantum Gravity with Lorentz Invariance. But it doesn’t. If you calculate the expectation value of the angular momentum operator, then that will respect rotational symmetry, yes. But that’s because the eigenvalues, here comes the relevant part, take on both positive and negative values, so they can average to zero. The eigenvalues of the area operator in LQG, in contrast, are all positive valued and have a lower bound. Consequently, the expectation value for the area in loop quantum gravity is bounded from below. It can’t transform under the Lorentz-group. Mathematical fact. Of course Carlo knows this. Everyone who works on this stuff know this. They just repeat this angular momentum story because it sounds superficially plausible if you don’t know anything about quantum physics. Now you can say, alright, the area can’t transform under Lorentz-transformations. So maybe there’s some quantum stuff going on and weird things happen. Yeah, actually Carlo and Simone said that in their paper. And that’s also why some people in loop quantum gravity said there ought to be deviations from Lorentz invariance. I tried to tell them long ago that this can’t work because these deviations would inevitably be so large we’d have seen them already. They didn’t want to hear that. There are still people writing papers about this nonsense."
@@pokerandphilosophy8328 You´re right, I´m member of the channel and have earlier access to the videos, and she cutted indeed some technical details (I remember the thing with the negative and positive eigenvalues). Perhaps it´s possible, before the vid is published? In earlier videos, in which she noticed failures, she took off the whole thing and uploaded it completely new.
Not sure, why she cutted some parts, cause the criticism about Rovelli is still in. Maybe, she thought, that the vid is technically to difficult for most of her audience, which would be unecessary for her message.
@@Thomas-gk42 I'm subscribed but I'm not a member. I think the edit came at least one day after the video was widely released. One viewer had made the following comment: "For a theory to have Lorentz invariance doesn’t mean expectation value of the operators must be zero. Having Lorentz invariance just means the theory transforms (in some well defined way) under Lorentz transformations. Take a single particle State in quantum field theory. The momentum isn’t invariant under Lorentz transformations. And it’s expectation value isn’t zero. It transforms under the Wigner little group transformation. I actually think Rovelli has a point. You can write down your states in terms of observables which aren’t Lorentz invariant, so long as the transformation properties on the states transform under some well defined transformations under Lorentz transformations." Sabine also had three blog posts where the issue the Lorentz invariance in LQG was broached upon.
Well, I trust Sabine!
### Catchphrase
"Feel the Pull: Think Gravity."
### Super-Liminal Influencing Campaign
A super-liminal campaign might involve delivering the message in an unusually direct and intense manner, like exaggerated enthusiasm or unexpected interruptions. But instead of screaming, imagine a deep, resonant voice saying, *“What’s holding you down? Explore gravity’s invisible power!”* on every channel at a heightened volume, but not quite shouting. You want to create intrigue and curiosity without overwhelming or turning people away!
DONT APOLOGIZE!! That Witten thumbnail was the most hilarious thing I’ve seen in a while 😂
Will be stealing from you ✌️
In all seriousness, if the physicists the thumbnail is making fun of are so humorless or uptight that a meme offended them, then it just proves the lack of confidence these scientists have in their own work. If anything, it goes to show that Sabine’s concerns are totally right, in that these people are just churning out mathematical word salad that doesn’t really further our understanding of Nature or reduce our uncertainty regarding current problems. It *would* be the case they’re just taking (mostly)tax payer money to play this stupid game modern scientists play where it’s more about showing off to your peers than actually solving problems.
Causal set theory also violates Lorentz invariance, but at high energy scales close to the Planck scale. Untestable. As for your earlier video Brian, the cited experiment was not necessarily applicable to LQG, given the scales. There are plenty of theories and models that have arguably untestable features, including inflation and prior epochs.
Sabine is my queen
And mine. ❤
Yooooo😮Thats heated. I think gravity is a wave. Space acting like it’s own substance creates a gradient. Like a liquid shadow wall space constantly caves around our earth, and other masses. Not to mention, but when you’re attacked to an object at velocity all you know is that speed. Any movements off the mass must be extra energy to escape it. I know you guys know that, but think about it? We are traveling at 70,000 MPH around the sun. That will stick you to an object just because of the matching velocities.
"Brain is is this true, as I am told, that you put a video out..." I love that it implies he didn't even watch it. He just said that someone else did and told him.
I have watched a few of your videos before. This time you earned a subscriber in me for your balanced view about this sociology of physics controversy as you rightly call it.
I like this drama, I may not be smart enough to have scientific opinions yet but i prefer it over celebrity drama that doesn't teach or help us progress.
14:14: we DO want Sabine and Carlo together in your show!!!!
You want shit !
If you watch Sabine's latest video she's clearly over it and thinks Quantum loop gravity is a total waste of time.
No, Brian has the better idea of keeping them separate, unless you are going to treat them like US Presidential Candidates with dead mics.
Please have Carlo alone specify in layman’s terms how the criticism from 2004 is debunked. Which LQG models do predict LIV (if any, and why) and which do not (and how and why). This point is crucial. 🤓
Baez cut the knots and dropped the loops and Greene just went Greye. Meanwhile, just like that Epic Rap Battle video between McDonalds and Burger King, neither side won, because Wendy crashed the scene at the last minute. So, Oppenheim is Wendy.
You and Eric have officially lost me.
I'm not a physicist but computer scientist. To me, patterns are everything. If code produces no tangible results yet consumes more and more resources, it's a defect. As it appears, the only reason the pattern hasn't crashed the 'system' is because more and more resources are thrown at the system. It's not meaningless to develop new tools and understanding. It looks more like small 's' science with big 'S' aspirations.
At the end of the day, if it doesn't allow a test, it isn't science, and if it does allow a test and that test rules it out, it is science but wrong. It does feel a bit like physics has lost sight of this.
Sabine, of course.
LQG stood for Linear-Quadratic-Gaussian; if you are done with Loop Quantum Gravity, can we have our acronym back?
Loop Quantum Gravity is a beautiful theory and in my opinion is closer to the truth than anything anyone else has put forth. What is your theory Sabine? You don’t have one? You just seem to tear everyone’s else’s ideas down but have none of your own. Loop Quantum Gravity and another theory called Emergent Gravity are both going down the right road. String theory is nonsense I agree with Sabine on that but don’t agree on much else with her. Carlo Rovelli is a brilliant physicist. One of the best of the last 25 years.
The best science occurs when you have deeply divisive opinions, yet when all sides have the core concept of accepting the possibility of being wrong.
I dunno, but if it came to a cage match , my money would be on Sabine. LOL
Just remember Tupac spelled backwards is still Caput ! 😊
I usually think of physicists as the epitome of logic and reasoning, but I had no idea that they could be so precious! (And I don't mean value.)
"Bollocks" are part of what make a steer so strong, and in fact aid in the creation of new life. I think it must have been the highest compliment.
Your content is amazing! Please keep it coming!
Has Sheldon Cooper made any statments on the issue?
I think Sabina is definitely the most solid voice in the science community today
The leading theorists in both string theory and LQG are desperately trying to avoid predictions that could be proven wrong - sad story.
Any theory of quantum gravity can only be tested in the domain of particle physics, because they are untestable in the domain of gravity and space-time. However, both string theory and loop quantum gravity are untestable in the domain of particle physics as well. So you need another approach. For example, the strand tangle model.
Sabine is a voice of reason in these troubling times.
Yes!
BRIAN, here's an experimental physicist, one who follows what the experiment dictates. WITH all respect, you are fooling yourself. YOU should pay attention to what SABINE is explaining than to follow your ego. Simply apologize in public with her, and we will see courage developing in you. Best for you, good luck, and take care of the taxpayers who support you.
LQG just seems to be correct. Sort of like General Relativity it just seems right. Sabine Hossenfelder is such a pessimistic annoying person. I can’t see how ANYONE in their right mind would work with her! It’s almost like she gets off on tearing others work down. Come up with a theory of your own Sabine! You can’t do it right?
Team Sabine. Period.
Your line of thinking about gravity being linked to universal motion and possibly emerging from the dynamic nature of the cosmos is intriguing and resonates with several existing frameworks, but it doesn’t neatly fit into just one named theory or school of thought. However, there are some areas of physics and cosmology that explore ideas related to this concept. Here’s an overview of some relevant frameworks that might be connected to your thoughts:
### 1. **Mach’s Principle**
Mach’s Principle suggests that local physical laws are influenced by the large-scale structure of the universe. In essence, the inertia of an object is somehow related to the distribution of mass and energy throughout the entire universe. While this doesn’t directly address gravity emerging from motion, it aligns with your thinking that local phenomena like gravity could be influenced by the global structure of the universe and its state of motion.
- **Relevance**: Your idea that motion and gravitational forces are interconnected on a cosmic scale has similarities with Mach’s Principle, which implies that local motion could be tied to the universe’s large-scale motion.
### 2. **Emergent Gravity and Holographic Principle**
Physicist Erik Verlinde proposed a theory known as *emergent gravity*, which suggests that gravity might not be a fundamental force but rather an emergent phenomenon arising from the underlying microscopic building blocks of space-time, similar to how temperature emerges from the motion of particles.
- **Relevance**: Your speculation that gravity could be related to “emerging from motion” and that it might not be a “standalone” force parallels the idea that gravity could be an emergent property tied to deeper structures of space-time.
### 3. **Dynamic Space-Time and Gravity**
There are various theories in cosmology that explore the relationship between space-time dynamics and gravity, such as *quantum gravity* theories and *string theory*. These frameworks try to understand gravity as a manifestation of space-time geometry influenced by quantum fields or strings.
- **Relevance**: When you discuss “motion creating gravity” and “the fabric of existence,” these ideas have echoes in quantum gravity research, where gravity emerges from deeper geometric or quantum structures of space-time.
### 4. **Shape Dynamics**
Shape Dynamics is an alternative to General Relativity, where gravity is understood through the evolution of spatial conformal geometry. Instead of focusing solely on the curvature of space-time, it looks at the shape and motion of spatial configurations.
- **Relevance**: This theory considers the evolution of spatial configurations over time and could offer a new perspective on how gravity and motion are intertwined.
### 5. **Cosmological Constant and Dark Energy**
Your idea that gravity could be tied to a universal expansion, where everything is constantly “falling” or moving outward, could be connected to concepts involving dark energy and the cosmological constant. The accelerated expansion of the universe suggests there’s a repulsive force (often attributed to dark energy) counteracting gravity on large scales.
- **Relevance**: If gravity is linked to the universe’s expansion and motion, exploring how dark energy and gravity interact could be relevant, especially when looking at gravity’s role on the largest scales.
### Summary
There isn’t a single named theory that completely captures your line of thinking, but it seems to align most closely with ideas from *emergent gravity*, *Mach’s Principle*, and certain interpretations of *quantum gravity*. These theories attempt to describe gravity not as a primary force but as something arising from deeper, more fundamental dynamics, whether through motion, information, or energy distributions in space-time.
While this isn’t a comprehensive list of related theories, it should provide some starting points for further exploration and alignment of your thoughts with ongoing discussions in theoretical physics. If you’re interested in delving deeper, exploring Mach’s Principle and emergent gravity frameworks could be particularly rewarding.
While I was in undergrad and hanging out with a friend of mine that was in the physics program (I’m a biologist), I joked to her that at the level of abstraction that current theoretical physicists were operating, a theoretical physicist is one stupid assumption away from becoming pure mathematicians.
This “joke” isn’t funny anymore.
At this point, publishers should demand a comprehensive list of mathematical and physical assumptions being employed for the theory developed in a manuscript, regardless of how trivial. A policy where theorists are given a SMALL budget of unverified assumptions should be employed. For example, your models should be based on wholly established physics, data or results from the experimental literature, and ONE “free” assumption. Then see how high that rocket can fly. One freebie seems harsh, but thinking about this stupid idea a little more, I realized that such a harsh constraint might actually make theorists think harder or more creatively. Nothing forces out of the box thinking like restraints that have to be overcome.
“We haven’t the money, so we have to think!”
We need to consider that there may be an infinite number of disparate models that all test right, because our ability to verify is bound by our understanding of the universe. It's a paradox : We need the models to design the observations, yet we need observations that are not informed by the model. This means that we may well only be able to make discoveries - i.e. verify our hypotheses or simply stumble upon them, by chance.
Hi, I just wanted to say I appreciate your position on not trying to offend other experts and be charitable towards them. This reminds me of Leibniz's saying that you "shouldn't offend accepted sentiments", phrase which has been very much criticized, but that other philosophers like Isabelle Stengers (a conational of mine and a friend of late Bruno Latour, since you mention sociology of science) reactivate today, by saying that either in science or in politics, the goal is not to crush an opponent but to compose a common world, and for this you have no choice but to live with the other and have to find a way to express what you mean and what's important to you without trying to destroy others' views, because that closes the space for relationality and change instead of opening it. And in this time of strong polarization, seeing someone who simply shows he has respect for the people he talks about and is not there to offend them, is very appreciated. Looking forward to more videos !
The physics version of Mortal Combat!
It made sense to develop the model of loop quantum gravity. You wanted to see how a discrete space would behave in reality. It predicted that light speed should differ based on wavelength. This was falsified!
Now, there is no reason to add non linear terms to loop quantum gravity. Why would you do that? The question is, what does the new theory test? What are the additional terms for?
If you create a discrete space and then use error correction, you are no longer in a discrete space.
I am by no means a loop quantum gravity expert. I have no idea how the exact theory works. All I know is that they divide space in triangles and that the area of triangles has a specific meaning. And that's it.
The scientists need to convince us. That's their job. And so far I haven't seen a convincing reason to continue research into loop quantum gravity.
There’s no war. Sabine is right and rovelli is just a mediocre self appointed “great physicist” who underdeveloped an aldready wrong theory.
IMHO physics has a fundamental problem due to the fact that physicists are willing to label (or consider) some theories "laws". The problem arises from the fact that the term "law" places artificial boundaries on the subject matter that causes anomalies to be (basically) ignored. A good example of this is equating over-unity with perpetual motion. If a claim of over-unity is made it can immediately be shot down by stating that over-unity allows for perpetual motion and the second "law" of thermodynamics tells us that is an impossibility. The truth is over-unity in a closed system is quite easy to achieve but will not allow for perpetual motion as they are two totally different processes.
The interaction of two or more magnetic fields is an active physical force which constitutes work. Suppose we have two beams situated parallel to one and other, each with a pivot at its center point. If we attach a magnet to one end of each beam so the magnets are repelling each other this will cause the other ends of the beams to be forced together in a pinching motion. A modern neodymium magnet has a theoretical lifespan of approximately 1000 years and considering that a 2 inch Nd cube is capable of almost 500 lbs. of physical force it has an energy density equaled only by a nuclear reaction. Now suppose we place a scale between the pinching end of those beams to measure the ACTIVE force created by the interaction of those two IMF's (Independent Magnetic Fields, magnets). At over 800 lbs. of active force this small device will very quickly "pay off" its energy deficit and then continue to output an active force (as shown on the scale) for hundreds of years. This is not only over-unity in a "closed system", it is over-unity on a massive scale, yet it doesn't automatically allow for perpetual motion. My point being, we shouldn't limit knowledge by placing artificial boundaries (laws) within which all scientific research must be conducted.
I don’t understand why names that are in pubic papers need to be redacted. I also don’t understand why the names of those who have come on the channel, and therefore publicly made statements, need to be unsaid:.
Discussion must continue as no one is declaring a final solution to the origin of Gravity. In a recent post Sabina showed that the understanding of Loop Quantum Gravity has nodally connected strings. This cannot be the reality as such a structure would leak energy across Field causing an eventual uniform energy level. The Field String Loops must be isolated to preserve the Gravitational Field Intensity Gradient.
My theory is Susy loops cross SU 69. It is conformal and cyclical
These criticisms of other physicists are healthy and encourage people to think in different ways without holding grudges against others.
Dude, if you personally know Carlos Rovelli and consider Lee Smolin a mentor and had him on your podcast… f’ing email them before making a video debunking their life’s work… it’s not rocket science doc.
What ever the right theory might be... I just have a feeling that it´s not string theory...
No rapper ever took on Wu Tang Clan, like, EVER, because - and I know you know this one - Wu Tang Clan ain't nothin' to fck with! 😊
It looked like gangsters/mobsters beating the sht out of someone but when they looked up close it was the universe, galaxy, sun, moon, and loop quantum gravity from the future beating up string theorists. They said "don't ever describe us" lol jk.
From what I understand the strings in "string theory" are so small that they would possibly never even be seen or measured.. Is that a theory of 😮
If you want science to be pure and intellectually honest - you need to pull the financial incentive out of the scientific endeavor. Period. Even then you're dealing with ego issues (which, honestly, would be much easier to deal with if monetary incentives weren't there to bolster beliefs about one's own scientific endeavors) ... but still. First step is nixing the financial incentive, second step is teaching everybody how to self-check their own ego.
When did scientists become such drama queens? Grow some and admit failures, even when you tried for years...even Elvis stopped trying acting after a decade and got back to performing music.
!!
BK: Use my Mass Threshold test for Dice Induction. 9.0 grams each was good for me.
Brian struggling to justify LQG. Why are you sacred of Carlo. What's wrong be string monopoly if string theory can bring every field of physics even conciseness. Meanwhile loop quantam gravity can't even try to solve Information paradox.
Another from the 90s: “Can’t we all just get along?”
Please have Sabine and Carlo on at the same time! Yes!