joigus

That's what I believe.

Nice historical account. Thank you.

=> Newton pairs => No contribution to overall motion => Not significant to COM evolution equations => Again. Rotation of one part not relevant to COM coordinates motion => No. Fictitious forces only relevant to objects moving with respect to non inertial frames (nut, bolt, etc.) subject to acceleration. Not relevant to COM motion. => Already addressed. Non-sequitur => Already addressed. Non-sequitur That's exactly what I think. There will also be a push and pull effect along the axial direction, to be studied in terms of action and reaction, if you will. Again: no overall momentum. Even though the detailed analysis would be quite involved. Assuming there's no friction, any angular displacement would result in a linear displacement, depending on the pitch of the screw. As said, and so far unanswered, the Lagrangian formalism makes it quite transparent that there can be no thrust for the COM system. It is true that the Lagrangian formalism can only be applied to conservative systems. But friction would only make it worse, not better, for the OP's claims.

You cannot dismiss essential points by saying they are "just assumptions" (to be addressed later) and then rush to mention in passing Planck's length (or a tiny fraction of it?), alleged axial anysotropies in the CMB (unobserved), etc. and then expect everybody to believe these bizarre phenomena that would require a complete re-work of everything physics is based on, all coming from a simple diagram. Your machine cannot turn the world as we know it upside down in one fell swoop. The physical principle you're up against is even valid for systems of quantum fields and is a version of Ehrenfest's theorem. I would (and will) demand nothing short of arguments of such dazzling clarity as to make me think it's worth giving up everything I've learnt during a lifetime. 1) Momentum conservation is tied to space symmetries 2) Fictitious forces only appear in non-inertial systems 3) Internal constrictions can always be resolved into action-reaction pairs in the inertial frame (I told you why this is necessary to be able to apply Newton's laws either to whole systems or to their constituent parts) 4) Mass transfer only results in thrust when mass is permanently ejected, not when it's kept inside the system May I also remind you of the adage, "Extraordinary claims require extraordinary evidence." Carl Sagan

In what frame of reference? Ficticious forces only appear (as apparently reaction-less) in non-inertial frames. Are you sitting on the turning "nut" whence you're going to measure your ship's overall motion? That would be inconsistent. This very much reminds me of another thread in which a user has been rejecting special relativity for years due to the mixing in his mind of lines of reasoning that can only be applied to one or the other frame of reference.

In what frame of reference? You don't seem to be aware that accelerations are frame-dependent. You've been asked this before, I think. In a FOR sitting with the ship initially at rest there are no fictitious forces. There are Newton pairs, and they cancel. In the Lagrangian formalism, they're expressed as some kind of integrable constraint: f_1(angle)d(angle) = f_2(angle')d(angle') and they don't appear in the COM motion. You don't even have to think about them as "forces." Technically we know them as "ignorable coordinates." I wonder why. Edit: https://en.wikipedia.org/wiki/Noether's_theorem#Historical_context (My emphasis.) Edit 2: Well, they don't "cancel," as @swansont pointed out on a previous thread, as each acts on a different part of the system. But they can vectorially be added up in the eqs. of the overall motion and don't play a role at all in its COM motion. Sorry, I made a mistake. Ignorable coordinates are the COM coordinates (they don't appear in the Lagrangian.) The other aspect is the constraint: f_1(angle)d(angle) = f_2(angle')d(angle') So that the constraint is integrable and you can describe the internal motion by just one coordinate. Which doesn't appear in the potential energy (because there is no external potential) so that it is, in fact, ignorable too.

Do you realise that, provided the total system maintains its mass, and none is ejected to space, statements 4. and 5. are in mutual contradiction?

Thank you for the references. Yes, this (mild) scepticism has been in the air for quite some time. Back in year 2000 you simply could not say you had problems with Copenhagen's interpretation without being classed as a heretic. It was dogma, no doubt due to its astonishing calculational power. Adding to it was Von Neumann's impressive authority on the matter, that went almost unchallenged for decades. It is my posture that the standing uneasiness can be addressed through a concept sketched by John Bell's (one of the first Copenhagen's sceptics) notion of beables. If you wholeheartedly accept the fundamental complex-number mapping of "reality" that QM persistently suggests, you can complex-parametrize these states (the way you usually do in QM) and further assume that part of these quantum-dynamical variables can never be measured --overall phase, gauge arbitrariness, spin projections that are not being measured... What you see in an experiment would just be certain real-number projections of these essentially complex states. IOW, any physical system would package a residual internal entropy that cannot be set to zero by experimental determinations. Again (mathematically) IOW: Quantum states can be set in eigenstates of complex operators that are not Hermitian (those would be the beables, what physical systems "are",) but measuring processes (and their outputs) must be represented by Hermitian operators and their eigenvalues (those would be the observables, what systems "look like" to other systems, which we can call observers.) That would be the reason why pure quantum states cannot be generally purely, unambiguously, "coloured" (in my analogy). They would be chameleonically coloured (in your 1st-reference's parlance.) They always look "coloured" whenever I look at them. But they are only "complex-coloured" internally. Still IOW: they have complex colours; I only see real colours.

Exactly my usual points about this question. Correlations are there since the very start of the state preparation. So nothing non-local is implied. This is the problem: Suppose elementary particles (say, electrons) are coloured balls. Balls can be found to be in any colour state as referred to a basis R, G, B, and you have devices to measure this "colour." You set both balls to be in an overall state that is white (colourless). So there is perfect anticorrelation; when one of them is found to be at R (total redness) the other one is found to be at GB (total anti-redness). For this you need a specific "redness" detector. But you can not say the ball was red before you measured its level of redness. And the reason is that whenever you measure a different colour component (say, brownness) the particle appears to be either brown or anti-brown (whatever that decomposition is in the RGB basis.) You see our predicament: How did the particle "know" I was going to measure the level of "brownness"? If my particle produced "anti-brown," sure enough, the other one produces "brown." The problem, thus, is not any communication bridge between the particles. The problem is your classical mind: Your classical mind demands the particles to possess an attribute (namely, definite colourness) that is not there. The property that is packaged in the quantum state is a predicate about both particles, which, when referred to your classical mind, can only be expressed as this predicate: "Whatever the colourness of particle (1) is measured, particle (2) will produce the corresponding anti-colourness if the same colourness component is measured." You can write down this property quite simply: J = C_i(1) + C_i(2) = 0 for any possible i-projection in the colour space. But you cannot attribute any particular C_i(1) or C_i(2) separately.

Here's the essence of mass transfer as applied to obtaining thrust: In your system. Where does delta(m) go? If delta(m) stays in the system. How does it cyclically go back while the net result being to impinge some momentum to the whole system in every cycle? The three of us, @swansont, @Ghideon , and myself, have expressed interest in this question, at some point, and I think all of us sense an underlying confusion between two very different kinds of so-called "reactions." Can you, please, address this in some detail so that we can proceed to other points? Edit: I took a quick screenshot from the Wikipedia image, https://upload.wikimedia.org/wikipedia/commons/4/42/Var_mass_system.svg as the SVG format doesn't display well.

First, there is no centre of the universe. The universe is pretty much homogeneous and isotropic on the scale of super-clusters. What you say contradicts GR, which we know to be a very good approximation to the large-scale structure of the universe. Second, if such "centre" existed, and the angular velocity increased as you approached it, there would be noticeable optical effects, as well as on the CMB. Third, a null speed of light anywhere is inconsistent with relativity, which you use in your paper. Fourth, how you relate quasi-particles (the domain of which are many DOF systems) with your 2 DOF system is completely obscure to me. Is this a new physical concept? If so, how do you define it in such a way that it doesn't coincide with the common concept of quasi-particles? I stated it because the impossibility to obtain momentum "for free" is valid even in contexts where Newton's 3rd law is no longer valid. You seem to be forced to appeal to cosmological models that you haven't justified or mentioned, but in passing, and after you were pressed for explanation. If you're going to change the very concept of space and claim the existence of a special "centre of the universe", why not mention it from the start? Conservation of total momentum is a consequence of the action for the system not depending on COM coordinates. I'm not aware that your model depends on cosmic coordinates. Where in your diagram are those cosmic coordinates? It doesn't show up in the model. Your mentioning of coordinates relative to a "centre of the universe" came from out of the blue when you were pressed to explain your model as relates to general conservation principles.

As Swansont says, non-inertial forces only appear in a non-inertial reference frame. If you want to analyse whether momentum can appear for the COM frame, you must set yourself on an inertial frame. And you'll see it can't. These reciprocal Newton pairs disappear from the overall motion. The Lagrangian treatment makes all this very transparent. Is this your pre-print?: https://vixra.org/pdf/2010.0034v1.pdf In this paper, either you, or someone who's of the same mind than you, try to extend the concept to special relativity. It doesn't work either. In the realm of SR, neither Newton's third law is valid, nor the concept of force is useful anymore. But the impossibility of getting COM motion from internal actions persists. So you're up against something very deep and very robust. I don't know what an "Euler inertial force" is. But googling for it produced this pre-print and a handful of other results (only 2 Google pages.) It doesn't seem that the scientific community is very much aware of this concept. Inertial (fictitious) forces are relevant when you have external fields (centrifugal barriers come to mind.) But the planet that's falling in the grav. field of a star is not an inertial reference frame --consistently with Swansont's assertion. They are also relevant if you try to walk on a merry-go-round (centrifugal and Coriolis), but again, you're not in an inertial reference system. A merry-go-round's COM cannot start moving as a whole as a consequence of (internal) Coriolis and centrifugal forces. A spinning top can move, but it's subject to external forces (friction.) What you suggest would require to totally rethink the concept of space. This goes deep.

Infinitely many times differentiable. Exactly. It's a topological concept. Its adherence (the set of all its accumulation points = points that can be reached by limits) is contained in it. Sorry, I don't understand. Interferrable?

? (My emphasis.) By highly mathematical I meant something like one of my old teacher's book on exact solutions in GR. It started with "the universe is a C-infinity differentiable manifold, dense, simply connected and boundary-less" --something like that.

I have several issues with this statement, and other careless statements like this. Just to clarify, because the quoting function makes it look as if you said something, which you didn't. Again: I didn't say this. It's on the abstract. But thanks a lot for your reply, Markus. No ofence taken, @MigL. I know. Thanks for clarification. Good points here. I'll go over them more deeply as soon as I have the time. The moment you introduce matter travelling on background geometry you change the metric is a deep observation. Then, I also find an almost insurmountable amount of practical objections. Like accretion disks I mentioned. Perhaps also, the rigorous solution should include quantum mechanics, as @Kartazion suggests. From what I've read (in a hurry) by Markus, the only classically consistent solutions to me would be cyclic, so as not to have problems with causal paradoxes. But what about quantum mechanics then? Sorry I'm being so sketchy. Not much time.

Generally, I agree with you. In fact, I don't think time travel will ever be possible. My interpretation was that they claim to have provided a possible mechanism. Here's what I interpreted as the claim: So I was not being that generous, if you think about it. Not really. Hypothetical time travel uses curvature, and time dilation is a different thing altogether and does not require curvature. Perhaps someone can provide a more complete explanation. Well, spacetime from bits requires quantum mechanics and the holographic principle. Conjectural time travel is based on classical GR.

Scientists from the University of Queensland claim to have found a possible mechanism for time travel. Laypeople-level account: https://www.uq.edu.au/news/article/2020/09/young-physicist-squares-numbers’-time-travel The paper: https://iopscience.iop.org/article/10.1088/1361-6382/aba4bc/pdf The abstract: The paper is highly mathematical, and I haven't found the time to take a more detailed look at this topic. I've just learnt about it. It seems that the key idea is to find plausible trajectories in phase-space for particles in the background geometry. That wasn't very informative. Sorry I can't say anything else significant right now. Any comments welcome. Edit: Whenever I think of these mathematical solutions, I can't help picturing the quite terrifying accretion disks of black holes... You know what I mean.

Electrons are not older than the universe. They are probably remnants of baryogenesis. So in that sense they're a tiny speck of time younger. Particles generally don't have distant information stored in them. That is a very rare condition. You must keep coherence for the entangled particles for very long distances to show such effect.

Yes, I realise. When I suggested that "what if" it wasn't in a strictly deterministic sense. When I said that, out of the top of my head, I pictured it like a series of arrows, conditioned in turn by the internal logic of the language. Plus also implications in the other direction (physical --> linguistic.) So I suppose the landscape would be pretty complicated. You tell me. But if we continue this conversation we may awaken the balrog of free will that lives in the depths of this forum.

Unfortunately, the pioneer (as I'm told), the scientist who discovered the CRISPR gene (totally irrelevant to the research, I assume) was left out. https://en.wikipedia.org/wiki/Francisco_Mojica

Well... I didn't say exactly I believe it. I believe nothing. I just said "what if...?"

What if language/ideas is a self-organizing superstructure that's using us to build something we cannot intuit yet? I think that's very much what's happening, actually.

And you do well. Everyone is unbelievable. Can you believe yourself? Humans should stop believing each other and themselves. The sooner the better. Let alone God. A better world might result.

In my case, it had nothing to do with god; it was that the process of believing itself ground to a halt. I no longer believe anything.

Maybe it is.