Simple geometric proof GR's GW's are impossible

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Q-reeus, Jul 7, 2016.

  1. Q-reeus Valued Senior Member

    Messages:
    2,533
    At the 1957 Chapel Hill conference, Feynman (as 'Mr Smith') was credited with a stroke of brilliance in settling an argument over whether GW's (gravitational waves) were real, via his simple 'sticky bead' argument: https://en.wikipedia.org/wiki/Sticky_bead_argument#Feynman.27s_argument

    But was it really brilliance or basic conceptual blunder that incredibly has held sway in the GR community ever since? Let's see, by stepping back from the trees, and viewing the forest as a whole. That is, let's see if the ubiquitous deforming ellipsoid '+' and 'x' polarizations, as per standard illustrations e.g.
    https://en.wikipedia.org/wiki/Gravitational_wave#Effects_of_passing
    which are supposedly locally experienced, actually makes geometric sense when viewed on a global basis.

    The basic thing about such GW's is their purely transverse traceless nature - purely spatial component shear deformations entirely transverse to the propagation vector k.
    [Leaving aside pedantic arguments where the observer may hypothetically have some huge transverse Lorentz boost relative to the distant GW source.]

    To pin it down as simply as possible, take the case of a single linear quadrupole oscillator. The quintessential two masses vibrating via a coupling spring. Which by analogy to an electric dipole oscillator in EM, is the primitive from which the far-field radiation of any other source distribution can be built via combination of such primitives.
    Well at least for the monochromatic GW field, which is all that need be considered to come to a decisive conclusion.

    We note that the intensity pattern has a maximum in the transverse plane (equator), diminishing to zero at the poles. See e.g.
    http://www.roe.ac.uk/~lmb/animations.html
    Also, far-field '+' GW polarization is aligned with projection of the oscillation axis z.

    Please Register or Log in to view the hidden image!


    Consider then the accompanying png illustration. A central mass-quadrupole oscillates along axis z, and we consider the far-field effect at an imaginary spherical shell centred about the oscillator. The local or 'tree level' view is illustrated by the two smaller ellipses, centred about and orthogonal to the arbitrary radius vector k. Which here lies in the equatorial plane, thus normal to the oscillation axis z. A passing GR style GW supposedly will deform a circular array of beads as shown - stretching/squashing in a plane normal to k and with ellipse major axes aligned along alternately z, and a tangent to the equator at that radius. The generalization to arbitrarily oriented radius vector k is hopefully obvious.

    But now we go global i.e. 'forest level' view. Instead of Feynman's short stick-and-2-beads though, here it's been extended to form a continuous circular hoop lying on the equator (solid line narrow ellipse), centred about axis z. With a uniformly distributed array of beads (black dots) free to slide along the hoop. Thus an array of Feynman's stcks'n'beads joined end-to-end. it matters not whether one allows gaps or not between such individual sticks - as will become very clear. Also shown (solid line) is a meridian line (line of longitude), and one can imagine a similar array of beads strung out uniformly on a hoop so oriented. The broken line ellipses will be explained later.

    The arrangement just described corresponds to an unpertubed notionally flat Minkowski spacetime. What will - no - what could really happen - if a GR variety pure tensor GW now arrives to perturb things? Only pure transverse shear deformations being allowed?

    Take firstly the case of the equatorial hoop. Supposing at a certain moment, the '+' polarization gives maximal circumferential dilation in the equatorial plane, thus simultaneously contraction along the meridians! Hmm... Which is simply the local 'deforming ellipse' case everyone is familiar with (vertically squashed small ellipse) BUT - extended globally. Does it take a huge IQ to figure out that the beads in the equatorial hoop, purely by symmetry, cannot have any motions along the hoop? The 'sticky beads' are stuck, even if perfectly frictionless! Dilation/contraction along lines of latitude makes zero sense. Something obvious when viewed globally ('forest view'), only seemingly sensible if viewed as a local perturbation ('tree level' view i.e. the small ellipses). Feynman got it badly wrong.

    Supposing one relaxes the pure transverse stipulation within GR and allows the equatorial hoop to 'breathe' radially. WE are necessarily introducing longitudinal GW's here! First observation is this runs counter to the usual argument that a 'rigid' hoop does not appreciably respond to the (impossible) shear deformations - only the free-to-slide beads should. Snookered there. But anyway, just suppose the hoop did freely expand. By how much would it need to radially expand to yield relative motion between the beads (but still with zero sliding along the hoop), consistent with a 1/r drop in GW induced transverse motion amplitudes? Which is supposedly what a GR GW will induce.

    The reader should quickly figure out that radial expansion/contraction amplitude would have to be, in the far zone, a constant entirely independent of distance r from source. In such a scenario, radial displacements (i.e. longitudinal, along propagation vector k direction) become overwhelmingly larger (proportionately) than any purported transverse motions. Increasingly so as r increases. Does that sound like a physically reasonable proposition?! Reverting to an array of Feynman sticks with gaps between them, which then admits free 'hoop' expansion, will not rescue things in the least. A constant longitudinal oscillation amplitude is simply unphysical.

    For the case of beads on a meridian hoop (or stick array if you wish), the situation is not quite so utterly obvious, since the symmetry constraint is not as totally restrictive. One could imagine the beads somehow alternately spreading apart along the hoop then contracting, with maximal motion amplitudes nearest the equator, diminishing to zero at the poles. However, we note that at the same time instant, contraction along meridians implies such an oriented hoop will want to deform inwards - conflicting basically with the 'need' of expansion for latitudinal hoops. Moreover the amplitude of such inward (or outward at the other half-cycle) motion would again have to be independent of r - for the same reason as for latitudinal hoops.

    The relevance to above of those dashed-line ellipses should now be evident - the hypothetical 'breathing' motions of latitudinal and meridian hoops are intrinsically out of phase. And of course such conflicting motions are a desperate concession running counter to standard GR GW lore. That only admits appreciable motion of the beads, not supporting 'rigid' hoops. Casting aside the hoops and beads, it should now be evident the supposed pure transverse pure shear metric deformations are self-contradictory. Pure shear deformations - torsional ones - are allowed on a spherical shell. But most definitely not ones consistent with GR's TT-gauge quadrupole mode GW's.

    Clearly, there is no way out of this mess for the standard paradigm. GR's and similar tensor gravity theories brand of pure tensor GW's are logical absurdities. Just why that wasn't realized at the very inception of GR is a matter for historians and maybe sociologists or even psychiatrists to ponder.

    So how then to explain the positive results now evidently confirmed by aLIGO?
    The reader is encouraged to take a good look at the following:

    http://arxiv.org/abs/1503.04866
    https://inspirehep.net/record/1353103/plots
    http://arxiv.org/abs/1502.00333


    Unlike the logically impossible GW's of GR and similar, Carver Mead's G4v vector GW's are logically self-consistent, having a close correspondence with those of an EM quadrupole oscillator.
     
    danshawen and quantum_wave like this.
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. PhysBang Valued Senior Member

    Messages:
    2,422
    Your bias is hurting your reading comprehension skills. The argument is not that gravitational waves do not exist, the argument is that they carry energy. Since the best argument for these waves is based on the energy they carry away from observed systems, this argument seems to be one in favor of the existence of gravity waves.
    Since this thread just began with your conceptual blunder, we have not choice but to side with GR and against your position.
    This is the kind of paper one should look at. Almost everyone working in relativistic physics expects that GR should be changed or improved in some way, and the observations of gravity waves are maybe one way to do it.
     
    paddoboy likes this.
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. paddoboy Valued Senior Member

    Messages:
    21,530
    The aLIGO experiment have observed gravitational waves from the merger of two stellar-mass BH's. The results match the predictions of GR as predicted for the spiraling and merger of two BH's and the associated ringdown of the resultant single BH.
    These observations not only confirm GW's, but demonstrate the existence of binary BH systems.
    So far two sets of incidents confirmed, details of which have been given in many papers in appropriate threads on these momentous discoveries.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. Q-reeus Valued Senior Member

    Messages:
    2,533
    Actually it's your own bias, comprehension, and reading skills that need severe adjustment. I nowhere there suggest GW's per se do not exist. Or did you not read the concluding part to #1 where links to and a positive spin on Carver Mead's G4v was given? Unbelievable ignorance! Try and follow my actual chain of logic, not some concocted straw-man of your imagination.
    And what 'conceptual blunder' was that exactly?
    Oh, so you did actually get to read the last part of #1 - yet still managed to screw up as per your opening comment implying I argued against there being any GW's.
    And it's not bleeding obvious to you that Carver Mead's G4v is radically different in character to GR?! Hence is in no way a 'modification' of GR but a true rival.

    Not surprising you get so much wrong. A quick search, and found the post where you give an 'I like' to the likely inebriation fueled rambling speculation at:
    http://www.sciforums.com/threads/is...ature-of-spacetime.156561/page-4#post-3383929
    Great judgement there, Just great. And I should take your vacuous, faulty commentary above with more than a grain of salt? LOL. If you want to tackle the actual logic of my #1, do so - objectively and sanely.
     
    Last edited: Jul 8, 2016
  8. PhysBang Valued Senior Member

    Messages:
    2,422
    OK, let's shake down your problem.

    You actually wrote: "At the 1957 Chapel Hill conference, Feynman (as 'Mr Smith') was credited with a stroke of brilliance in settling an argument over whether GW's (gravitational waves) were real,"

    You actually titled this thread: "Simple geometric proof GR's GW's are impossible"

    You have previously stated that you have a bias against GR.

    I don't care whether or not you think that some kind of gravity waves exist, your statements claim to take an argument that was used as part of evidence for gravity waves of GR as evidence against gravity waves in GR.
    Again, I don't care if you have some kind of crank gravity wave theory. The bead argument you referenced was about the gravity waves of GR specifically and used later as evidence for their existence.
    I'm glad to see that you commonly mistake aesthetic judgement for scientific judgement; it certainly reflects your approach to physics.
     
  9. Q-reeus Valued Senior Member

    Messages:
    2,533
    So far, a passable reassessment - to that early stage.
    Didn't take long to again go off the rails. Recall this piece of yours in #4:
    Positive wrap, but screwed reasoning about it implying a 'modification' to GR. That - Carver Mead's G4v - the link of mine you quoted there, is THE 'crank' theory I suggested had a chance of being right. Never claimed it had to be THE correct theory btw. And - Not my GW theory!! Savvy?! Make up your mind - you like it (G4v), or hate it, or what?
    There is some argument - like, that's not exactly what I wrote first off in #1? More irrelevancy. MY 'bead argument' later on in #1 is what kills GR's GW's. Showing how lame Feynman's original argument really is. But to see that, one needs to let go of blind ideological prejudice and actually think about it as actually presented. Hell, nothing complicated - purely geometrically imposed symmetry constraints.
    Oh, really? Sorry - I fail to see a fine distinction. In my book you give an 'I like' to someone's notion of reality, you are endorsing that notion. But whatever.
    [PS - this reply late owing to a power outage!]
     
  10. PhysBang Valued Senior Member

    Messages:
    2,422
    The problem is that you confuse legitimate attempts to add to GR with the rejection of GR entirely. You attempt to use legitimate science to fuel a hate-filled rant against Einstein.
    No, no it doesn't. You take it as given that there can be no "motion" along the hoop, but give no argument. Give an argument and we'll see if you have something.
    Sadly, this forum does not have a "I agree with your argument" button, it only has a "like" button.
     
  11. Q-reeus Valued Senior Member

    Messages:
    2,533
    A bald assertion, as others here are chronically prone to engaging in. Evidently you do not appreciate GR is uniquely defined by the EFE's. Set in stone ever since 1916. To modify at all is to reject it. The LHS of EFE's, neglecting iffy CC term, is not in dispute, but the RHS is. Yilmaz, and some others, recognized the inconsistencies by setting 'gravitational energy' as having no contribution to energy-momentum-stress tensor i.e. the RHS of EFE's. Robertson sets out the issues very clearly.
    Hate-filled rant? And you can point to anywhere I have expressed anything remotely amounting to hatred for AE, as opposed to disdain for the uncritical god-like status he has been given by others? Back that up with specific, in-context quotes, or retract. That's not a suggestion.
    Are you serious? You actually can read through #1 and never does the penny drop?! You tell me how it is logically possible for Feynman's beads, strung out uniformly on a circular hoop, centred about the oscillator axis z and in the transverse, equatorial plane, can possibly have any circumferential sliding motions along the hoop.That you cannot recognize the glaring symmetry constraint there is amazing.

    The sole possibility for relative transverse motions between beads (but no sliding motion wrt hoop) is if the array radially expands and contracts cyclically. Which immediately undermines the claimed pure transverse nature of purported TT-gauge GW's of GR. Requiring longitudinal waves. It's similar when considering beads strung out on a meridian line, but best to just have them free floating - which then makes it obvious any logically impossible pure transverse 'dilations' or 'contractions' could only occur if the meridian line expands or contracts radially. Thus not 'pure transverse shear'. And moreover with the opposite thus conflicting phase wrt equatorial bead array dilation/contraction. Conflict and absurdity on multiple levels.

    As soon as anyone actually attempts to provide an objective counterargument, it should be immediately obvious game is over for GR's GW's. One poster here, owing to his profound lack of sound judgement or any technical proficiency, badly confuses my total confidence in logic of #1 with 'arrogance and bluster'. How sad.
     
  12. PhysBang Valued Senior Member

    Messages:
    2,422
    Funny you should say that to change the EFE is to reject GR, but at the same time you bring up the cosmological constant. The history of the cosmological constant (like many other parts of the history of physics) shows that your claim is simply false. Einstein himself changed the EFE to add the cosmological constant. Then he removed it. Then came over half a century of debate and attempts to gather evidence to see whether or not to include the cosmological constant in the EFE. While some of the discussion included whether or not to replace GR with another theory, the majority of the discussion did not. Therefore the EFE is not some holy object that cannot be changed, lest we abandon GR entirely.
    For at least half a century there has been discussion on what side of the equation to put the cosmological constant (or equivalent). It is even possible that it belongs on both sides of the equation in some sense. I agree that Robertson sets out some issues very clearly: one issue Robertson sets out clearly is that he is looking at an improvement on GR, following on the work and methods of Einstein, not a wholescale rejection of it.
    Right there, you just did it, since you are imagining the "uncritical god-like status he has been given by others", especially in physics.

    However, we can also find evidence here:
    Here you are imagining, without mentioning what this supposed flaw is, something that is evident from before the theory was even fully realized. You are claiming that there is something fundamentally wrong in one of the theories used for some of the most highly accurate tasks done in the world today. You are prioritizing some fundamental disagreement you have with the theory over the empirical results it produces.
    Are these beads rigid? Perhaps you could address this and the possible internal pressures and stresses in the beads in your full argument.
     
  13. Q-reeus Valued Senior Member

    Messages:
    2,533
    A strange viewpoint imo, but peripheral to OP issue. The RHS - as it relates to role or not of 'gravitational energy', is the important area of contention - on that matter. To repeat. But still peripheral to OP topic.
    You might as well argue that GR is just improved Newtonian gravity, with merely a tweaked interpretation and a bit of non-linearity added.
    Insane logic. How does that observation, the truth of which is clearly evident in many media presentations, articles, best-seller popularizers, and gushing adoration from certain folk here for instance, amount to 'hating Einstein'. Trying to weasel out of an apology?
    Starts out supposedly backing your 'I hate Einstein' accusation, and quickly sidetracks to saying 'I have an issue with GR'. To the last bit; yes, of course - not in dispute! But totally irrelevant to your claim I 'hate Einstein'.
    WTF?! Where did that come from? How do you figure some utterly inconsequential stresses in beads could possibly have any appreciable influence on argument? Did Feynman mention 'bead stresses' as significant for instance? There will be an extremely tiny modification to gravitating mass of beads - that's it. Why not just assume unstressed - KISS principle? Try and be serious.

    Look, there is no need for sticks or hoops - that was just adapting Feynman's original scenario. And as for beads, well replace them with your favourite, unstressed point sized test masses. Floating freely in notionally flat background outer-space. But laid as per #1. Assume mutual gravitational interactions between test masses totally negligible on time scale during which a notional GR variety GW passes. Now try and defend GR's 'deforming ellipse' GW *local* shear strains as having any sense on a *global* basis. Just try!
     
  14. PhysBang Valued Senior Member

    Messages:
    2,422
    It is hardly a strange viewpoint given the tons of ink spilled about the cosmological constant in the last two decades and it is not peripheral to the questions you have been asking or the attitude you are taking.

    A nice history of the cosmological constant was done by John Earman in "Lambda: The Constant That Refuses to Die." Available at https://www.jstor.org/stable/41134106 and perhaps freely available at https://www.researchgate.net/publication/226966303_Lambda_The_Constant_That_Refuses_to_Die.

    If GR had included a gravitational force, then one could argue this. Einstein clearly, however, held the position that Newtonian gravity was amazingly correct in identifying and measuring the values of regularities in the available phenomena. Einstein seems to be advancing the basic methodology of Newton in many ways.

    Robertson is, as far as the paper you have cited, including all of GR, all theoretical apparatuses and entities included, and adding an additional factor to track.
    How many "Einstein was wrong" articles are published in pop science media each year? You seem to buy into some sort of deification of Einstein, I don't buy it. Your tone certainly seems to deride him and you have yet to deliver on a substantive problem for GR.
    Your "issue with GR" is some unknown problem that you identify with it from before it was published. How can an unpublished theory have a problem? You are imagining some kind of serious problem with one of the most effective physical theories of all time; that seems to me like irrational hatred.
    If you can't give a physical argument for your position, then admit it. I can't "be serious" when your entire criticism of GR comes down to "it's obvious" that your imagined scenario with few details is a problem.

    If there is no interaction between these point test particles and anything else, then how is it possible to do work to separate them? It seems that you are simply discarding an important element of the original thought experiment.
     
  15. Q-reeus Valued Senior Member

    Messages:
    2,533
    Another straw-man assertion from out of thin air. It is not bleeding obvious the interaction of interest is that of the metric perturbations - supposedly transverse shear ones - owing to a passing GW? One begins with an unperturbed configuration i.e. h = 0, and then works out the changes with wave present. Standard stuff.
    Well GW's do carry energy-momentum - you agree?
    I have to guess you mean the 'sticky' part of sticky beads-on-a-stick. As I explained last post, not needed. We assume an actual wave; no need to 'prove' they carry energy as was hot topic in Feynman's time then. And allow the test mass arrays to simply be markers - 'carried along' on the perturbed spatial metric.
    You are challenged to attempt to rationally justify that the local shear deformations - again Wiki reference:
    https://en.wikipedia.org/wiki/Gravitational_wave#Effects_of_passing
    can possibly make sense on a global basis. It will pay to review my #1 carefully before responding. Suitably modified with hoops/sticks absent. Or present if you wish - it won't matter re final conclusion.

    The rest of #54 is simply not worth dealing with given how you keep responding to those matters. But that quoted here, OP related, I will pin you to the wall over.
     
  16. Confused2 Registered Senior Member

    Messages:
    434
    Test of my understanding here:-
    Let's have a mass M that is sufficiently dense that it lies inside its own Schwarzchild radius Rs. The mass lies at the centre of a sphere of radius r.

    As I understand it Einstein/Schwarzchild would have it that the entire properties of M are accounted for when integrating out from Rs. There is nothing left below Rs to integrate which won't give you an unphysical >M result. This proves nothing except that I have faith in the people who have repeated this calculation many times.

    There are people who don't believe the entire properties of M are accounted for when integrating out from Rs. This proves nothing except that they don't have faith in the same people as I have faith in.

    If I am correct then the OP is about faith and lack of it - which is not proof.
     
  17. Q-reeus Valued Senior Member

    Messages:
    2,533
    A very bad fail re your 'Test of my understanding here'. It would help Confused2 (well chosen forum name btw), if you actually got the topic right to start with. What on earth is the connection, in your mind, between presumably BH mass calculations and my geometric argument regarding (typically extremely weak far-field case) purported GR variety GW's?
    I despair for this forum. Truly.
     
  18. PhysBang Valued Senior Member

    Messages:
    2,422
    What do you mean, you are the person saying to "replace them with your favourite, unstressed point sized test masses" and "Assume mutual gravitational interactions between test masses totally negligible". So, yes, you are claiming to ignore all interaction between these beads.
    Please, it's your "argument", work it out.
    I would love to "review" your argument, if you would be bothered to make the argument.
    I know that you do not want to think about just how much GR stays in the alternative theories that you think say that GR is totally wrong.
     
  19. Q-reeus Valued Senior Member

    Messages:
    2,533
    Wrong. I made it precise enough - ignore mutual gravitational interactions BETWEEN test masses. In other words, eventually they will mutually collapse inward as gravitating 'dust'. But on a time scale far too long to appreciably alter an evaluation of GW induced perturbations. You do realize I was in fact being far more careful to specify there than say the Wikipedia entry I referenced to? Which merely assumes the reader realizes the test particles respond only to the wave - not appreciably to each other.
    Seems one can never do enough to satisfy folks - always some confused slant will intervene to screw up intelligent discourse. Sigh.

    I sense from the tone of the rest of your #71, a decision to avoid any further engagement. So be it.
     
  20. PhysBang Valued Senior Member

    Messages:
    2,422
    Fascinating that you cut off the first part of my sentence before you decided to reply.

    You mean that you sense that I can't take you seriously if you won't actually wrote out your argument and rely instead on "obviously"? You are right.
     
  21. James R Just this guy, you know? Staff Member

    Messages:
    30,531
    Moderator note:

    About two-thirds of this thread up to this point consisted of pointless personal attacks. Those posts can now be found here:

    http://sciforums.com/threads/off-to...eometric-proof-grs-gws-are-impossible.157039/


    Please post on-topic. If you want to have a personal discussion with another member, please start a private conversation.

    Trolling of threads like this is unacceptable. If it continues, some of you will quickly find yourselves banned.

    Members are asked to report further attempts to derail legitimate threads with off-topic personal sniping.
     
    danshawen likes this.
  22. Q-reeus Valued Senior Member

    Messages:
    2,533
    Huh? OK - here again, your complete first para from #15:
    What was supposed to be thus taken out of context in my comment in #16? Something that should have been utterly obvious to you was made explicitly clear. And all you can do is bitch. And such has been your attitude from the start. I have a very clear criteria for judging sincerity on this sort of thing. My case was set out in #1.
    If you had legitimate comprehension issues with any part of that, and you claimed to, the obvious, sensible thing to do would be to quote relevant passages. And either pass specific criticism, or ask for clarification. Instead, you for the most part kept insulting me with the vague, generic claim 'none of it makes sense to me'. Implying I lack the capacity to communicate an idea.
    What nonsense! #1 is the 'written argument'! Again, apart from the initial quotes in #2 (one line repeated in #5), which you misconstrued, and in any case were entirely peripheral, you avoided referencing relevant passages from #1 that set out my actual case. Carefully avoiding to specifically critique, or ask for clarification, on the central arguments in #1, tells me thus you are insincere and out only to denigrate. I suppose out of total ideological commitment to GR.
     
    Last edited: Jul 11, 2016
  23. Q-reeus Valued Senior Member

    Messages:
    2,533
    OK so Schmelzer posted on this GW issue in (currently still!) p9 #165 in thread : http://www.sciforums.com/threads/a-simple-proof-einstein-got-it-wrong-with-gr.156996/
    And in #167 suggested I reference to it here. A bit awkward, but anyway...addressing to Schmelzer's #165:
    I will start for now with just the last line of your #165:
    You complain earlier about my 'vague words' in #1. Yet not once have you specified WHY any such longitudinal waves (assuming for now GR actually does allow such - it doesn't) should be invisible to aLIGO. Any real GW must be a metric perturbation, and having a wavelength, must have gradients i.e. tidal effects. So, please, precisely explain why they should be invisible to a detector designed to pick up general metric gradients. Or you are not aware aLIGO signature templates exist for all six possible GW mode classes?:
    http://relativity.livingreviews.org/Articles/lrr-2013-7/articlese5.html
    See 5.1.1 Tests of gravitational-wave polarization (Which btw clearly refutes your claim GR admits to longitudinal wave solutions.)
    A bit strange if they knew one or more of those modes were inherently invisible to aLIGO, wouldn't you think?
    Once above is sorted out, we can move on to the rest of your #165. But also, I suggest to reflect on #19 this thread.
     

Share This Page