# Compression of matter: Limit?

Discussion in 'Physics & Math' started by Dinosaur, May 24, 2018.

1. ### NotEinsteinValued Senior Member

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Indeed, conclusions drawn from GR are consistent with GR. But you are imposing an additional condition ('strict' equivalence principle), which doesn't appear to be required in (mainstream) GR, which that appendix also explicitly points out. So that would make the Schwarzschild solution bad in this GR+equivalence scenario.

That's what I meant, yes.

So that's not in the paper, but it's you that's making the claim that the equivalence principle must hold. Thanks for clearing that up!

(Irrelevant for this discussion.)

3. ### NotEinsteinValued Senior Member

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Hold it, I jumped the gun, but only slightly. Arxiv notes a "text overlap" with a peer-reviewed paper here: https://arxiv.org/pdf/astro-ph/0602453.pdf It shares one author.
Appendix F's opening:
So it is a viewpoint the author holds, although in Appendix A of the first paper this author doesn't push this position. So it appears this is indeed a fringe position.

5. ### Q-reeusValued Senior Member

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You keep misinterpreting for some unknown reason. 'Strict equivalence principle' is part and parcel of GR! That is, gravitational and inertial mass are precisely equal. Didn't know that? See e.g. 2.1 here: https://arxiv.org/abs/1403.7377
To avoid useless further postings, it *should* be a given that EP (either WEP or SEP) is never meant to strictly apply other than locally i.e. tidal fields i.e. higher order spatial derivatives are not relevant to validity of EP in either it's weak or strong form.
But it's not what you wrote!
Again, a misreading of both what Robertson and myself was stating. Do you accept that both WEP and SEP are notionally integral to GR?
What's at issue is the logical outcome of applying EP consistently. Again - can you find any way around the derivation of exponential expression for redshift given in Appendix A? Which is at variance with standard GR formulation - the one predicting EH's thus BH's!
Far from it. Again - show where there is any error in that GR undermining derivation! Taking into consideration above replies.

7. ### Q-reeusValued Senior Member

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You are now resorting it seems to a form of argument from (majority rules) authority! AGAIN - point to any error in the derivation of Appendix A! Failure to do so will be taken as an admission of defeat.

8. ### NotEinsteinValued Senior Member

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Then why does the peer-reviewed paper I linked in post #22 (sharing an author) state otherwise?

So... the scenario in Appendix A of the linked paper is wrong (or at least, different) in its application of the equivalence principle? I don't get your point here?

It was clear from context what the "first order" was referring to. Sorry it wasn't clear for you.

My opinion/view on this is irrelevant. I'm merely trying to figure out yours, and where it differs from mainstream GR.

Irrelevant. I've not argued against it at all.

The Schwarzschild metric isn't the only metric producing BH's, but I get what you're saying.

Still irrelevant.

False. I have not claimed mainstream GR is correct. I've merely pointed out your position is not mainstream.

Still irrelevant; I'm not arguing against the content of Appendix A, I'm arguing against the extrapolated conclusions you (and apparently, the author) hold.

That's not how logic works.

9. ### Q-reeusValued Senior Member

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You really should have read the entirety of: 3 'The Strong Principle of Equivalence' there. In that much ~ 10 years earlier paper, they were trying to point out a contradiction existing within adopting there a strictly GR paradigm! One that in Robertson's much later Yilmax centric article I linked to, is neatly and naturally avoided! Keep up!
No it's not wrong. How do you get to think it's wrong? In particular, how could the redshift expression derived there be wrong? POINT TO THE ERROR.
No it's not irrelevant since you claimed - wrongly - that Appendix A I linked to implied failure of EP. It didn't. That was your faulty reasoning.
Oh? Yet I see no acceptance from you of validity of the strictly logically derived exponential redshift expression! One at variance with GR redshift expression. To repeat.
No - you are avoiding the issue. If that redshift exponential expression is correct, GR is wrong. Period!
No. You have tried, unsuccessfully, to discredit the findings by Robertson that undermine validity of GR.
Content and 'extrapolated conclusions' are one and the same in final analysis there. AGAIN - point to any actual logical or arithmetic error in appendix A!

10. ### NotEinsteinValued Senior Member

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Oh, you mean the part where they say that in order to enforce the SPOE requirement at all, they have to go outside of GR?
That's quite obviously not a "strictly GR paradigm".

You have missed my point. Appendix A in the later article makes no claims that GR is wrong. Only that the Schwarzschild metric violates the SPOE.

Are you making the claim that the SPOE is always, globally enforced in nature?

I would prefer it if you stopped putting words in my mouth. I've nowhere claimed that the derivation is incorrect; I've previously explained this to you.

I haven't made that claim. Please stop putting words in my mouth.

So? Doesn't mean I believe it's wrong. I merely have no opinion on it at this time.

Yes, which is why I'm trying to figure out why you are jumping to the conclusion that GR is wrong, and not SPOE.

As I've explained multiple times now, it's not necessarily GR that's wrong. It could be SPOE too. I'm trying to figure out why you rule out that possibility.

I haven't tried discrediting anything. And once again, why wouldn't it undermine the validity of SPOE?

And my pointing out the fringiness was more because of the location you are posting this in on this forum. We have a separate subforum for such material.

Point me to the lines in that appendix where the author concludes GR is wrong (and not SPOE).

Again, I've not made a claim that there's a logical or arithmetic error in Appendix A. Why do you keep insisting I provide evidence for a position I currently do not hold, have made no claims for, and I've expressed no opinion about?

11. ### originIn a democracy you deserve the leaders you elect.Valued Senior Member

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It is obvious from your posts that you are just a troll and most assuredly a sock puppet. It is just a matter of time until you are gone, so I bid you adieu.

12. ### Q-reeusValued Senior Member

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And? I pointed out they were in that 2006 article, pointing out an inconsistency (with already then extant observational evidence e.g. intrinsic magnetic moments for 'SMBHC's'), by sticking within GR paradigm! Which disallowed intrinsic SMBH magnetic moments. Savvy?
Nonsense. Appendix A makes no such claim of violation of SPOE. Your interpretational error. It does however undermine GR given SM is the unique solution of GR's EFE's. To repeat!
Of course not. I made it perfectly clear last time, SPOE is a locally enforced equivalence, as is WPOE. Those two differ only wrt inclusion of 'gravitational energy' in respect of equivalence of gravitational and inertial mass - or not. Try to avoid raising spurious issues.
No words have been put in your mouth on this. You wrongly and repeatedly claimed Appendix A undermined SPOE. Whereas you have continually misrepresented (charitably - confused) my position.
Then form one and state it unambiguously! Shouldn't be hard to do. Or you are still struggling to fathom Appendix A?
You must know very well the two stand or fall together! Or have you forgotten Einstein's 'happiest moment of his life'? Or maybe you are ignorant of that SPOE, while implying 'gravity gravitates', only requires that any 'gravitational field energy' obeys gravitational mass = inertial mass. Assuming the latter equivalence holds, it's an untestable principle entirely consistent with 'gravitational field energy' = 0! The latter in fact consistent with GR's Ricci scalar R = 0 for all GR vacuum solutions! Unlike in Yilmaz gravity where gravity genuinely gravitates.
Explain precisely how it would!
So you are already maneuvering to have this thread banished to the fringes?!
How about the last sentence there. Why do you keep obfuscating?
Really? So, given how straightforward that derivation is, WHAT IS YOUR DEFINITE OPINION!

Last edited: May 30, 2018
13. ### NotEinsteinValued Senior Member

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But they didn't stick within GR paradigm, as I pointed out.

I never claimed it violated SPOE. Let me spell this out for you: they take SPOE and GR, use the Schwarzschild metric, and find a contradiction. So, the options are:
1) They made a mistake in their derivation. Nobody is claiming this.
2) SPOE is wrong.
3) GR is wrong.
4) The Schwarzschild metric is not a valid metric when using SPOE in combination with GR.
(Or a combination thereof.)

You are the one jumping to conclusion 3. I'm merely pointing out 2 or 4 are also possibilities that aren't excluded in the Appendix as written. So the interpretational error is all yours.

And there you go assuming SPOE is correct again. Please provide evidence for this claim.

Follow-up question: are you claiming SPOE is valid within the scenario described in Appendix A?

Again you are putting words in my mouth. I have made no such claim. I've addressed this misinterpretation of yours above.

Alright, what is your position then? Is it that GR is wrong? Because that's the vibe I got from your original post, especially because you brought up that notion in the first place: "consider the possibility GR is fundamentally flawed".

Why must I? Anyway, it's irrelevant to the discussion at hand.

You do know that insults are against the forum rules, right?

If that's the case here, then why hasn't Robertson's work let to the downfall of GR yet? The paper is almost 2 years old, and yet it isn't cited by scientists as the nail in the GR-coffin at all... A conspiracy perhaps?

I don't see how any of that is relevant to the discussion at hand?

Well, fringe science belongs in the fringe sections; it's what they're for.

This sentence?
How is that not compatible with conclusion 4? Or conclusion 2?

Why must I form an opinion about something that's irrelevant to the discussion at hand?

14. ### arfa branecall me arfValued Senior Member

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One take I've seen recently about how quantum information is stored by a black hole:

a) Trying to reconstruct some history, of say, a classical object that fell in at time t, is in principle a possibility if you wait long enough. You have to wait because large enough black holes take a long time to evaporate (10^66 years, say).

b) How far does light travel in the time it takes for enough information to 'leak out' so the history of some object can be reconstructed, by measuring quantum information--in this case Hawking radiation--and how is that connected to the information paradox (if it even is)?

c) Because of entanglement, basically the emerging information is in some form of an interference pattern that needs to build up. A threshold has to be reached where enough information has been 'uncompressed' to reconstruct any history. But black holes evaporate in an exponential way, so most of the information is emitted near the end of the lifetime. This is all a consequence of superposition of quantum states, interference and entanglement are just different ways of "measuring" superposition (or something like that).

15. ### Q-reeusValued Senior Member

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Which sums up my opinion of your continued either profound confusion or devious troll bating tactics. Either way, it's not worth my time responding further to such. Have a nice day.

16. ### NotEinsteinValued Senior Member

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How is trying to stay on-topic a "devious troll bating tactic"? It's actually a defense against it!
How is me not having an opinion on something I haven't studied in detail "profound confusion"? Jumping to conclusions is!

Contrary to you, I've spend some time looking into this. Carroll describes a scenario very similar to this in his book "Spacetime And Geometry: An Introduction To General Relativity" (2003 edition). On page 52-53 he derives a formula for gravitational redshift from what he calls EEP (Einstein Equivalence Principle; basically Strong Equivalence Principle, but for gravity only). In this derivation no GR is used (no metric, no curvature, just the EEP with a constant $g$ gravity field). Then on page 216-217 he derives it again, this time from GR without explicitly applying the EEP. He also uses the Schwarzschild metric. He obtains an exact expressing (eq. 5.103):
$\frac{\omega_1}{\omega_2}=(\frac{1-2GM/r_1}{1-2GM/r_2})^{0.5}$
And then he demonstrates that for $r\gg 2GM$ this indeed reduces to the equation found earlier using only the EEP. This is why I asked you how locally you think the equivalence principle applies: apparently, in the Schwarzschild metric, this is (must be?) $r\gg 2GM$.

This also demonstrates a linchpin in the derivation of the author of Appendix A:
Carroll's derivation doesn't adhere to this either. But apparently, Carroll is okay with a first order approximation away from the event horizon region. There seems to be a difference between the conditions that must be met, as set by EEP (Carroll) and the SPOE (Appendix A). Again, this is why I started asking you about "how locally is local enough"?

So when we get close to actually understanding where our differences comes from (via the four conclusions), you throw in the towel? Well, as a person once said:

17. ### Q-reeusValued Senior Member

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When there is continual misinterpretation/misunderstanding (charitable view) or willful distortion (what it seems to me) of plain statements by both Robertson e.g. Appendix A, and myself, no matter how many times various points have been clarified, it's futile and time-wasting to continue. Some folks here enjoy endless exchanges that go nowhere useful. Not me. Have a nice day.

18. ### NotEinsteinValued Senior Member

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You mean, like you've been doing to me? How many times have I had to point out you misinterpreting/misunderstanding my points?

At what point have I distorted any statement Robertson made? This accusation is new to me!

And how many times have you been putting words in my mouth?

How many times have you demanded I have an opinion on some matter?

And how many times have you failed to clarify various points?

I don't disagree there.

So now that we're actually getting somewhere, you bail?

Perhaps you should've not constantly tried derailing our discussion with irrelevancies then?

I most certainly will. Same to you!