Comments by "Lepi Doptera" (@lepidoptera9337) on "The experiment that could save physics" video.

  1. It's not a matter of technological barriers, at least not in the sense of e.g. LIGO. It's a matter of new theoretical ideas with regards to the question if there could be non-classical effects of gravity that are strong enough to cause a detectable signal. Personally I don't think so. Experiments of this kind are often based on some unusual physical assumptions. An entanglement experiment, for instance, is not sufficient for quantum gravity because classical gravity entangles systems just fine. Entanglement per se is not a quantum effect. A quantum effect detection requires quantized energy exchanges and those are just so far down the rabbit hole that it's not even fun talking about them.
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  2. No. :-)
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  3. We can imagine a lot, but reality will be much more mundane. Absolutely nothing interesting will show up.
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  4. I didn't read your comment, either. Are you happy? ;-)
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  5. Newton does not describe the world correctly. It's an approximation that fails in many different ways. Having said that, it works just fine for the attraction between your body and Andromeda. That's why one can't learn anything new about gravity by looking at that phenomenon. It only tells us what we already know.
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  6. We aren't. We have been trying to find a way to make it fail for many decades. The problem is that the darn thing is quite robust. ;-)
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  7. No. :-)
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  8. Why are you telling us that you didn't study science? ;-)
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  9.  @ar007r  I am just trying to understand the deepest levels of human psychology... why the intellectually lazy have such a desperate need to portray themselves as knowledgeable. ;-)
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  10. Entanglement is neither a necessary nor a sufficient condition for the formation of interference patterns. It's completely orthogonal to the actual condition, which is coherence.
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  11. The space around you isn't expanding. What you need to do is expand your attention span while reading the science news. :-)
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  12. Save physics from Karening? :-)
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  13.  @Randomstu1988  Dang! I didn't see that. I need to level up on my sense of humor. ;-)
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  14. You haven't even began to think about beginning to think. ;-)
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  15. Lately I did notice a strong increase in people who are seeking attention on the internet. ;-)
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  16.  @biomechanique6874  Why are you projecting your narcissism? I don't care about that any more than I care about your failed science education. ;-)
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  17.  @biomechanique6874  You clearly had a horrible time in school. ;-)
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  18.  @biomechanique6874  Why are you telling me that you were the only child in your home schooling family? ;-)
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  19.  @biomechanique6874  I don't do commercial religious bullshit, either. ;-)
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  20.  @biomechanique6874  I am giving attention to lonely children on the internet. ;-)
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  21. Entangled quanta aren't influencing each other. You simply don't understand the meaning of the word "entanglement". ;-)
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  22. No, spacetime being quantum doesn't mean that everything else would have to be, too. Water is made of quantum fields, but you won't find any quantization in water waves. ;-)
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  23. Atoms are an emergent phenomenon. They come from weak observation.
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  24. Just ask that semiconductor fab engineer about that... oh, wait, he's a physicist. ;-)
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  25.  @onetruekeeper  Your CPU wants you to hold its beer. ;-)
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  26. It's just a fact.
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  27.  @peterjohn8625  Why do facts make you angry? ;-)
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  28.  @peterjohn8625  No kidding. ;-)
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  29. Einstein never said that force does not exist. :-)
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  30. Entanglement is simply the consequence of a conservation law for a multi-quantum state. Do we know that conservation laws exist? Yes.
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  31.  @thomassimmer5186  What gobbledigook is what? ;-)
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  32. Yes, but I don't think it works well. Entropic gravity seems to have some fundamental issues.
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  33. Yes, the theory does make us expect there to be perturbations, but they would be way too weak to lead to measurable shifts in energy levels or in measurable line broadening.
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  34.  @Darisiabgal7573  First of all, photons don't travel. What travels is the electromagnetic field. What you are describing in the quantum field picture is called a scattering process. Scattering involves an energy exchange with another field and such an exchange between the quantized em field and the quantized gravitational field is not possible in first order because of momentum conservation. It would have to be something like a gamma-gamma-graviton process, which most likely has near infinitely low probability at these energies. The only effective interaction that is left is therefor the classical gravitational field with the classical electromagnetic field and we have measured that, already... it's the deflection of light and radar by the sun in our solar system.
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  35.  @Darisiabgal7573  A photon is not a perturbation of the field. A photon is the amount of energy that the field exchanges with an external system through the electromagnetic interaction. A graviton is the amount of energy that another system exchanges with the gravitational field. The problem is that the classical fields are simply the averages of many such exchanges. That averaging process removes the quantum mechanical characteristics of the underlying quantum field and leaves us with a classical phenomenology. To "see" the quantum nature of the field requires a measurable effect of interactions with one or, at most, a few quanta of field energy. If we need many such exchanges, then the quantization becomes invisible and we are left with the classical field. We know how the classical field behaves. What we don't know is how the process looks like when we have low order scattering like in a process that can be described by two photons, two photons and one graviton out (if that is even a possible process, I am not a theorist, I am just guessing the lowest order based on spin). That process leaves such an incredibly small change in em field energy and momentum that we can't measure it.
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  36. Why are you telling us that you never took a relativity class? ;-)
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  37.  @patrickfuchs3859  Singularities don't exist. NEXT! :-)
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  38.  @patrickfuchs3859  Yes, that was nonsense. ;-)
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  39.  @patrickfuchs3859  Only from people like you. Not from me. I actually read his book. It's a masterpiece. ;-)
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  40.  @patrickfuchs3859  Yeah, I didn't read your nonsense. ;-)
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  41.  @patrickfuchs3859  I just didn't read it. It looked like total gobbledygook, possibly written by ChatGPT. I can give you attention, anyway. That's what you are here for, isn't it? ;-)
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  42. Superposition is a property of the theory. We engineered it in there. It's not a property of nature. Neither does it have to be, you just have to work on your physics intuition a little longer to differentiate theory and reality. See you in twenty years. ;-)
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  43.  @K.A7287  Your problem is still the same. You don't understand what is in superposition: it's the wave function, which is an ensemble description. The quantum mechanical ensemble only exists in your mind. It doesn't exist in nature. Not only that, but neither does nature have a "position" property. Position is the classical average of many weak measurements. It's not something nature cares about to begin with at the fundamental level. That should be obvious from Noether's theorem. There is no symmetry that leads to a "position conservation law".
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  44.  @K.A7287  There are no particles. Nobody has ever seen one. We try to teach even in high school that "quanta" are small amounts of energy. Entanglement is simply the correlation between energy transfers in different parts of a system. What causes entanglement? The symmetries of the system. What's a symmetry? It's the absence of a symmetry breaking mechanism. So... entanglement is something that happens because something else doesn't happen. ;-)
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  45.  @K.A7287  I don't know what any of that gibberish means. Different interactions are showing very differently in physical data. An electron track looks different than a muon track looks different than an alpha track looks different than a gamma track... even on visual inspection of a bubble chamber or cloud chamber photograph. The electronic readout of our modern detectors differentiates these different kinds of interactions even better. Just because you don't know what you are looking at doesn't mean that people who have studied high energy physics don't know. Are you trying to appear as dense as a Uranium 238 brick on purpose? ;-)
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  46. You shouldn't care about any of this until you are willing to put the years of learning in that it takes to understand any of it correctly. ;-)
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  47. Why are you angry that some people are smarter than you?
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  48.  @esecallum  You are angry, again. ;-)
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  49. Time is that which the clocks show. Always was, always will be.
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  50. No. :-)
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  51. No, one does not need an accumulation of mass to have quantum gravity effects. That's the difference between classical physics and quantum physics. Well, at least that's one of the differences.
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  52. Gravity is not a force, but language is a b... :-)
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  53. A quantum is "a small amount of energy", i.e. the noun "quantum" already describes a change in a property. The adjective then describes scenarios that describe or are based on changes of properties.
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  54.  @martf1061  Energy is a system property. A quantum is just a small amount of it (compared to the human sized "Joule" scale). There is nothing here that we didn't explain in quite some detail at the high school level, it just happens that people don't realize that it's exactly the same as mechanical energy exchange because there is so much unnecessary noise about it in the "public science" arena.
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  55. We know that spacetime geometry is an approximation, we just don't know what it approximates. It's not the math that is a problem here, is the experimental inaccessibility of the layer of physics that causes spacetime.
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  56. Entanglement is simply conservation laws at work. Does angular momentum conservation apply to macroscopic objects? Yes, absolutely. That's how it was discovered.
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  57. Singularities of that kind don't exist. Not even in general relativity. A rotating, charged black hole does not have a singularity.
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  58.  @SlaveRebellion-yn5wy  Yes, and that only exists in a single, unphysical solution of a non-rotating, non-charged Schwarzschild black hole. It's a mathematical artifact, even in the theory that ignores matter completely. For physically relevant black holes "the singularity" is either ring singularity or a 2 dimensional sub-manifold that seems to act like the surface of a white hole. The passage through that surface seems to take you to another universe from which you can watch what happened in "the old country", but which won't allow you to return to it. I have seen other interpretations of that metric, but the "final resting place" is NOT a singularity in any of them. This is yet another case where the public has been ignorant of the pesky details of a theory that is extremely difficult to calculate and interpret.
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  59.  @SlaveRebellion-yn5wy  If gravity is a quantum phenomenon, then even talking about "the singularity" is as futile as talking about "particles" in non-relativistic quantum mechanics. These are all failed semi-classical mental models that people just can't let go off because we are still teaching 19th century nonsense at the high school level. Point is... singularities don't exist, not even in the classical case. Neither do "particles". These are all mental artifacts of poorly written Newtonian physics and classical electrodynamics textbooks. The "point anything" model kind of self-combusts even in classical physics as soon as you dare to look at it closely for more than a few seconds.
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  60. None of this will get us anything. This isn't a question that can be resolved with desktop physics.
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  61. Awh, let me give you some attention. ;-)
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  62. Except for every day of my life. ;-)
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  63. Everybody can make up anything and write a book about it. The problem with Rovelli is that he hasn't proposed even one testable scenario in his entire life despite his endless exploration of rabbit holes.
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  64. That has been proposed by several theorists... but none of these entropic arguments seem to work all that well. I like them, but at the end of the day it has to make the right predictions, which it seems it doesn't.
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  65. "Friends" like her. ;-)
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  66. Why would it? What you call collapse is actually the removal of energy from the system. This can only happen through gravitational waves and they are way too weak to remove even one quantum of energy from any of these systems.
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  67.  @pawelczubinski6413 Only if you remove energy from the system and gravitational waves can't do that.
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  68.  @pawelczubinski6413  That's not the physics behind all of this. That's the solution theory of the Schroedinger equation as presented to you by von Neumann, a mathematician who at the time was deeply involved with functional analysis. A quantum measurement, as in ONE detection of a quantum of energy, is the exchange of one quantum of energy between the quantum system and an external system that we usually call the "measurement system". What "collapse" means is simply that the quantum system before the measurement had either less energy or more energy than after the measurement. If it has the same amount of energy, then a measurement did simply not take place and the ensemble of the system can be described by the unitary evolution of the ensemble's wave function. If you read Heisenberg's papers on matrix mechanics (1925, I believe), then you will find that the energy differences between "before the measurement" and "after the measurement" (that's the amount of energy which we call "the quantum") are still part of the theoretical description. By 1932 when von Neuman writes his abstract mathematical treatise on the math of the Copenhagen interpretation, that immediate connection between the actual physics of quantized energy transfer and the "state" based theory of the quantum mechanical ensemble had been severed sufficiently so that future generations who are learning von Neumann's math were and are having a hard time to actually derive from it what happens at the level of the physical system. That's an artifact of the way we teach introductory quantum mechanics. We tell you the math but we don't tell you what it actually means. In this case, of course, you have to understand the actual physics of the process, the mathematical structure of the theory tells you absolutely nothing about what is going on.
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  69. Entanglement is the action of local symmetries on quantum systems. Either entanglement is real or there is no momentum and angular momentum conservation. Every traffic accident proves that there is. ;-)
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  70.  @PrintEngineering  There are no "measurement paradoxes". We know exactly what measurements are and what they do. There is just a lot of noise\nonsense about that on the internet. We also understand the processes by which entangled photon pairs are being created. The best known low energy process is just not easy to explain because it involves a solid state system.
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  71. We have been doing experiments on small masses and gravity seems to be the same as for planets... so, no, that's probably not it.
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  72. Even Newton doesn't treat gravity as a force. Most people simply don't understand the subtleties of Newtonian physics, even though we try to introduce them to pseudo-forces. I don't know what you believe that "we believe". This isn't religion and even if it was, you would be wrong. ;-)
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  73. Or... you could learn the meaning of the word "theory". ;-)
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  74.  @Paul-li9hq  What do you need gravitons for? Nobody has ever seen quantum gravity. Physics is the rational explanation of observations of nature. It does not have to explain things that have never been observed. That's NOT theory. That's speculation. Until somebody sees quantum gravity effects the entire graviton concept is just intellectual nonsense.
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  75.  @Paul-li9hq Yes, you are wasting your time because I am a physicist and from my point of view you are simply talking nonsense, my friend. Neither your home schooled use of the word "theory" nor your desperate need for attention impress me much. That you have never read a theory book about gravity is obvious. I would lend you my 1250 page copy of Misner, Thorne, Wheeler "Gravity", but what would you use it for? As a doorstop? ;-)
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  76.  @Paul-li9hq  See, your need for attention is getting the best of you, again. ;-)
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  77. We tried that. Doesn't work well. ;-)
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  78.  @janbielecki94  Did we try god view? Yes, absolutely. You can hear about that in every church. The world is 6000 years old, the devil put those bones in them hills and Jesus will be back tomorrow. Like I said, it doesn't work well. ;-)
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  79.  @janbielecki94  Emergent gravity does not make foolish claims like "you have to understand the entire universe before you can understand anything". Only attention trolls and religionists do. :-)
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  80.  @janbielecki94  Those kinds of statements only come from people who had a hard time understanding the few simple rules that we were trying to teach them in school. ;-)
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  81.  @janbielecki94  I can talk about any topic with you. Why don't you pick something that's more fun than physics, which you clearly don't want to understand? ;-)
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  82.  @janbielecki94  The rules are very simple, you just didn't look them up. It can all be written with a few symbols. Only the consequences of the rules are very complicated. ;-)
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  83.  @janbielecki94  I don't disagree with anything. All I said is that we tried emergent gravity and it doesn't seem to work well. I already noticed as a third year student that general relativity looks like a thermodynamics system. So what? So has probably almost everybody who doesn't have a cauliflower as a brains and who took a GR class and a thermodynamics class in the same year. But noticing that the equations look similar and then making a new theory out of them is the difference between a mediocre physicist and a genius. Using the words "emergent gravity" doesn't make you a genius any more than noticing that the equations have the form of thermodynamics differentials makes one out of me. Plenty of theorists have gone down that rabbit hole and they came out soiled... because that's what is in most rabbit holes: crap. :-)
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  84. Probably as soon as you are willing to pay for that nonsense. :-)
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  85.  @Ilovelamp-rw4et  For a really well designed experiment near the physics limits? Easily $200-500 million. You could probably build something on the cheap for $50 million plus launch cost, but why would you if you really care about the best possible null result? ;-)
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  86. What she does is entertainment. :-)
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