# Simple geometric proof GR's GW's are impossible

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

1. ### quantum_waveContemplating the "as yet" unknownValued Senior Member

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Thanks for clearing up the nonsense. Are you saying that there are gravitational waves called for in the maths of an apple falling to the ground, as well as for binary black holes?

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3. ### SchmelzerValued Senior Member

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Yes. But of course for the apple they will be soooooooooooooooooooooooooo small.

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5. ### quantum_waveContemplating the "as yet" unknownValued Senior Member

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I get it, thanks for that clarification. So the path that objects follow, geodesics I think, work within reasonable limits until the energy involved becomes meaningful. Is it the case that when the velocities of the objects involved begin to reach a meaningful percentage of the speed of light, that there would then be enough mass loss through those waves to effect the path, relative to the geodesic?

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7. ### SchmelzerValued Senior Member

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The geodesics is, of course, only an idealization - for a pointlike test particle with negligible mass. Not that it is not accurate. To compute the trajectory of the Mercury around the Sun it was accurate enough to compute the perihelion shift. But it would of course fail for the computation of a nearby satellite, who would be influenced by the mass of Mercury too. Which the gravitatational field of the Sun, with Mercuries geodesic trajectory on it, would not describe.

The velocities of the binary pulsars, which have given via their energy loss the first implicit evidence of gravitational waves, are, of course, not small. https://en.wikipedia.org/wiki/Hulse–Taylor_binary gives a 7.5 hours orbit period and a size at maximum of 3,153,600 km. So the light needs 10 sec. for this. 7.5 hour for what light needs $\pi$ times 10 sec is not what I would name a "meaningful percentage".

8. ### quantum_waveContemplating the "as yet" unknownValued Senior Member

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Thanks again.

It might not be a meaningful percentage, but it is sufficient to encourage physicists and engineers to build LIGO with a good hope of detecting them.

Another question: The loss of mass to gravitational waves, though trivial, would seem to result in there being a corresponding amount of energy in space, in the form of gravitational waves. And if so, then the question, even the apple falling to the ground would contribute to that total energy in space in the form of gravitational waves, though almost nothing, infinitesimal to the extreme for the apple? Would that be a reasonable statement?

9. ### SchmelzerValued Senior Member

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Yes, even the apple would contribute a little bit. But in comparison with the good old heat death this is nothing which would matter.

10. ### quantum_waveContemplating the "as yet" unknownValued Senior Member

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Thank you, and your help is much appreciated. As a result, I have some clarification to make to my update out in the Fringe, and I plan to acknowledge what you have contributed and explain how it fills one gap.

Q-reeus: I have wondered, since your OP, what your view is on quantum gravity, and does it come into play at all in your world view?

Last edited: Jul 21, 2016
11. ### paddoboyValued Senior Member

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Similar of course to the fact that even light/photons will add some curvature to the geometry of spacetime, due to its momentum.///but sooooooooooooooooo small as to be insignificant.

12. ### paddoboyValued Senior Member

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arxiv.org/abs/1602.03841
http://arxiv.org/pdf/1602.03841v2.pdf

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant’s mass and spin, as determined from the low-frequency (inspiral) and high-frequency (post-inspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasi-normal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parameterized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 1013 km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.

The paper concludes with.......

The detection of GW150914 ushers in a new era in the field of experimental tests of GR. The first result of this era is that, within the limits set by our sensitivity, all the tests performed on GW150914 provided no evidence for disagreement with the predictions of GR.

Last edited: Jul 21, 2016
13. ### quantum_waveContemplating the "as yet" unknownValued Senior Member

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I want to take note of the mention of the heat death, while at the same time being respectful to Q-reeus, since he may have some interest in not straying too far from the OP. To me this ties in since the heat death of the universe is very GR, and Q put a period on the statement that he is not invoking GR, thus a conflict that could be addressed "on topic" IMHO.

My enlightening discussion with Schmelzer about energy from objects being emitted into space in the form of gravitational radiation, which at extreme energies is capable of triggering a LIGO alarm, also leads to a conclusion that the gravitational waves from the binary black holes, and all the apples falling to Earth, and even of all individual particles of which objects are composed, once released into space, would presumable stay there, traversing space indefinitely; the infinite reach of gravity, or should I say of gravitational wave energy.

That would play nicely with the concept of the heat death which also features the accelerating expansion of the universe and the eventual distribution of all energy into a slowly equalizing, expanding ball of high entropy energy, without functioning particles, and with no usefulness left at all. That is supposed to be the final outcome under GR. But not if if GR is not invoked.

So to conclude this thought, Smelzer, if he invokes GR all the way, lives in a universe that gives us all a cold chill in the end, while Q-Reeus lives in a universe that may not leave us out in the cold. Given a choice, I'm with Q on the issue of the the long term livability of the universe.

14. ### Q-reeusValued Senior Member

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QG plays no part in respect of GW issue relevant to OP. It's assumed by most to be the natural union of QFT and GR. Absolutely necessary in most theorists minds in order to resolve the pathologies in classical/semi-classical GR like 'BH singularities' and ' BH information paradox'. Not at all required in a theory like Yilmaz gravity where such pathologies cannot arise. Unfortunately, the latter theory also predicts the same transverse pure shear GW's as GR, which thus puts a question mark over it's overall viability. With G4v afaik there is also no room for such pathologies but details are scant.
Let's stick to or rather get back on track to OP topic.

15. ### Q-reeusValued Senior Member

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Huh? I have mentioned heat death anywhere but here and now this thread? Fate of universe is an entirely separate cosmological topic. Please focus on OP topic.

16. ### SchmelzerValued Senior Member

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It does not really matter. Anyway the standard heat death would happen much earlier. And according to standard $\Lambda$CDM the fatal effects of the exponential accelereation will start not that long after they start to become visible, so that this is, from a cosmological point of view, near future. In my theory, the universe will be oscillating, so that there will be similar nice times as today in far future too. But, of course, there would be no hope for anything to survive the next big bounce. For humankind all this is irrelevant, the problem how to survive the next 20 years is a more serious one.

17. ### quantum_waveContemplating the "as yet" unknownValued Senior Member

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Sorry Q-Reeus, I'll wait for some new on-topic content. Let me just close with a response to Schmelzer. The main complaint with the oscillating universe is that it can't completely reclaim all of the energy from afar before the next expansion cycle. Even if it is a small amount of EM that can't be reclaimed, entropy will eventually win, and there will come a point where there isn't enough useful energy to produce the next expansion cycle. My model defeats that complaint.

18. ### SchmelzerValued Senior Member

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Why this? In its most dense state, there will be equilibrium. No reason to assume this equilibrium has to differ from the next one.

19. ### Q-reeusValued Senior Member

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James R, take note of what is happening here, and recall how 'discretionary judgements aka executive decisions' have already resulted in this thread being culled 3 times ostensibly owing to off-topic chit-chat and worse. Easily an all-time record surely. Take note of my comments here:

20. ### SchmelzerValued Senior Member

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Sorry for answering questions I'm asked to answer. It would make sense to split this part.

Once you refuse to answer questions about the topic itself, it happens that the discussion shifts away, there is anyway nothing to discuss on-topic.

21. ### The GodValued Senior Member

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Q-reeus,

But you are not coming on topic. I had asked you a very simple question in # 159. If solution is perfectly alright then what is the significance of global inconsistencies. Are you suggesting that transformation is bad, frames are bad.

Once you acknowledge that GW causes proper distance changes as per GR approximations, then how can you find fault with what aLIGO detected and its interpretation...

22. ### Q-reeusValued Senior Member

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Wrong. I try to limit discussion to and answer on-topic queries relevant and genuine. The problem is few have the interest in or capacity to see through disingenuous BS having mischievous intent. In your case the latter is not an issue, but comprehension is.
Count how many times we have gone over and over the same ground. Why is that necessary? Have you taken up the simple challenge in #62 as I asked in the, as of this writing, still current new new #153? How about getting down to doing that. Then come back and talk meaningful stuff. It WILL help much to just DO IT!
Profound misunderstanding of everything I have tried to convey, over many posts, from various angles. Sigh. Just DO what I ask above. OK?

23. ### The GodValued Senior Member

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Q-reeus,

See, you know what you are talking about, but it is not necessary that I or many here have understood that so far. That could be a cause of poor explanation or real difficult stuff to comprehend.

I have not even crossed the initial bar....Tell me precisely how a perfectly correct solution of a consistent theory can be globally or locally inconsistent ? IMO you cannot claim inconsistencies whatsoever while acknowledging the correctness of the solution.