Chinese Scholar Yang Jian liang Putting Wrongs to Rights in Astrophysics

How is the EFE not related to the EFE?

Yes, that's my point. They are incompatible.

No, I've been saying all this time they aren't compatible. Is your English really that bad?

Because I'm taking your advice, and am ignoring the minus sign? But I guess your own advice is too confusing for you. I'll try and include the minus signs.

Yes, and as one finds out when one learns mathematics: \(4\neq-8\).

 

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If my foundation is too poor, then so is Einstein's, Adler's, Weinberg's, Carroll's, your Chinese author's...

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Just for shits and giggles, let's look at Misner et al (1973); I'm using the online version available on Archive.org, which appears to be a first edition print.
Page 222, equation 8.37: the definition of the Ricci tensor. The contraction is on the third index, and indeed its terms are a minus sign off from what Yang uses.
Page 406-407, the EFE. Notice the \(+8\), which is incompatible with Yang's \(+4\) (and remember that Misner et al are using the different Ricci tensor definition, so there's actually a sign difference here as well).

Another source that says Yang is wrong. Who would have guessed? I guess Charles W. Misner, Kip S. Thorne, and John Archibald Wheeler are all wrong too?

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our discussion may completely not to involve the equation with coefficient 8, which corresponds to Carroll's definition for Ricci tensor. And only consider the equation with coeifficient -8, which corresponds to Weinberg's definition for Ricci tensor. Yang's work is to modify the equation with coefficient -8, of course, insisting in Weinberg's definition for Ricci tensor. the 4 is Yang's modification to the -8, obvious this need your own calculation if you want to see reason

 

"Page 406-407, the EFE. Notice the \(+8\), which is incompatible with Yang's \(+4\) (and remember that Misner et al are using the different Ricci tensor definition, so there's actually a sign difference here as well)."
the 8 and the 4 are not relevant at all, it doesn't matter whether they are compatble or not. As for that Charles W. Misner, Kip S. Thorne, and John Archibald Wheeler are all wrong , this is unworthy of your surprise , the geocentric theory was wrong for thousands of years, everyone was wrong.

 

Which, seeing as the EFE is at the heart of GR, means you are no longer doing GR at all. The theory of gravity you are working on doesn't apply to our universe. In fact, with the changed 'strength' and the flipped sign, I don't think it's reasonable to call it gravity at all!

All six sources now provided (three by you) agree: the absolute value of the coefficient is \(8\), not \(4\). So even if you are able to resolve the minus-sign business by messing about with conventions and definitions, Yang is still wrong.

Yes, let's. That equation proves that Yang is wrong, because: \(-8\neq4\).

Yes, and this modification is wrong. Weinberg's derivation of the EFE clearly shows this. If you disagree, please point out the mistake that Weinberg made.

No, it doesn't. There have been mentioned six sources in this thread that give derivations of the EFE, all resulting in the same EFE (when you take into account the differing conventions); three of these sources were provided by you. Yang is in direct conflict with all six sources; including the three sources you provided. Please point out the flaw in the derivations that these six sources have done.

So it doesn't matter that Yang is wrong in his derivation? If you don't care about correctness, then what the heck are you doing on a science discussion forum?!

 

about the modification from 4 to -8 we've calculated it countless times, and it's perfectly reasonable. For a person who can ' t complete the calculation , it ' s not eligible to deny.

 

It's perfectly reasonable to change the heart of GR by changing the 'strength' of curvature by a factor 2, and throwing in a minus sign? It's perfectly reasonable to get a different answer to a calculation that tens of thousands of experts on the topic over a 100+ year period?

I guess we have different interpretation of the phrase "perfectly reasonable" then...

Who said I can't complete the calculation? I'm merely relying on Einstein, Weinberg, Adler, Misner, Carroll, your Chinese author, etc. because I trust their textbooks have received more attention than whatever I could scribe onto a piece of paper in private.

But you are allowed to deny the validity of the works of Einstein, Weinberg, Adler, Misner, Carroll, your Chinese author, and those ten of thousands of experts on the topic over a 100+ year period, without providing even the slightest hint as to where they made a mistake? Sounds "perfectly reasonable" to me...

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The reasonableness of the modified equation lies first in it provides such the weak field spherical symmetry metric g-00=-1+2GM/r and g-11=g-22=g-33=1-2GM/r, and -1<<g-ij<<1 as i doesn't equal j, which make sure that geodesic equations return to relativistic mechanical equation in considering of speed of test particle, as we as make sure the speed of light is speed limit in weak gravitational field. before this scientists only required the geodesics equation can return to Newton law at low speed in weak field and obviously they ignored the velocity effect or failed to take account of high-speed situations. Now Yang mended this important lesson, which is definitely a step forward.

 

Here g-00, g-11, g-22, g-33, the "-" mean subscript. Note that the previous field equation with coefficient -8 provides
space-component g-11=g-22=g-33=1+2GM/r, and g-ij<<1 as i doesn't equal j,which cann't make the geodesic equation of high-speed particle return to relativisitic mechanical equation and neither make sure light-speed limit in weak field, and obviously there are shortcoming

 

According to you, Yang's EFE and everyone else's should thus match at low velocities, because under that limit both should result in Newtonian gravity. Please demonstrate that when \(v\ll c\) this indeed happens. I highly doubt it, because \(4\neq-8\), not even when \(v\ll c\).

(Please learn how to use the tex-tag on this forum. Or at the very least use "_" for subscripts.)

You are claiming that SR is not recoverable from GR (when using the usual EFE); in other words, that the Einstein Equivalence Principle doesn't hold for this EFE. Well, please explain that to, for example, these people:
https://www.quora.com/Is-special-relativity-a-special-case-of-general-relativity
https://physics.stackexchange.com/q...avitational-potential-from-the-metric-of-gene

 

https://www.quora.com/Is-special-relativity-a-special-case-of-general-relativity
https://physics.stackexchange.com/q...avitational-potential-from-the-metric-of-gene

Indeed I don't understand this form of file.

I do

 

GR should be indeed recoverable to SR, but the usual EFE indeed cann't make GR connect with SR in extreme case of weak field, namely not recoverable. It is Yang's work that achieved the recover . And the principle holds in any case, the equivalent principle is showed as geodesic equation without mass term, that is to say, that geodesic equations hold means the principle holds

 

What? I don't understand what you're trying to say.

Except that it does, as my links suggest. In fact, Carroll does this explicitly in his book on pages 50-53.

But this isn't unique to Yang's work; the usual EFE has this property too. That was my point earlier; a point you’ve apparently not fully understood.

 

Isn't there also a problem with the cosmological constant? Yang says it's out by a factor of 2. How does he recover the observed expansion?

 

Yang's EFE doesn't have a cosmological constant, because he apparently doesn't need it: heyuhua claims Yang's modification explains things like that without needing dark energy, etc.

 

What you say isn't real, like Einstein or others, Carroll didn't this connecting work with SR, that is , he only considered the low-speed approximation and neglected the question of high-speed approximation in the static weak field, which is very important to relativity

 

it isn't too real that Yang says it's out by a factor of 2. In Yang's articles there isn't the factor 2

 

indeed there is no cosmological constant in Yang's modification, but the Pressure term takes zero no longer, now it takes negarive, P=-rou, namely the negative value of cosmic density. So-called dark energy may be thought to absorb into pressure P , namely p is the comprehensive effect of ordinary stress and dark energy, and as for the dark matter needn't be considered again. So, the cosmological calculation becomes very concise

 

Sure, but you just admitted that Carroll thus does recover Newtonian mechanics in this limit, so the claim that only Yang does this correctly, is false. And while Carroll may not explicitly derive this for high speed cases, the two links I previously provided do claim to recover SR.

Please stop purposefully misrepresenting: there is a factor 2 difference in the absolute value of the coefficient of the EFE.

It isn't zero in standard GR in general either, so I don't know why you'd say that?

Does Yang derive the \(C_l\) of the CMB somewhere (see: https://en.wikipedia.org/wiki/Cosmic_microwave_background#/media/File:PowerSpectrumExt.svg )? That would be quite convincing that his EFE doesn't need dark energy.

As for dropping dark matter: how does Yang explain all these: https://en.wikipedia.org/wiki/Dark_matter#Observational_evidence ? It's quite clear dark matter is a local and stand-alone phenomenon, so getting rid of it by changing a global equation (the EFE) is quite suspicious...