Chinese Scholar Yang Jian liang Putting Wrongs to Rights in Astrophysics

[NotEinstein]

Here's a paper of Yang's:

http://pubs.sciepub.com/faac/3/1/2/index.html

Nice find! I personally like this part most: "Notice that Newton’s theory is the approximation of low speed of general relativity, and general saying, celestial bodies’ speed are not very high, therefore the generalization of Newton’s theory is just the result of general relativity and the practical significance is apparent." We're talking about expanding spacetime, but let's ignore GR.

 

[exchemist]

Here's a paper of Yang's:

http://pubs.sciepub.com/faac/3/1/2/index.html

Here's the first part of the conclusion which seems to summarize his ideas:

"While space enlarges celestial bodies and galaxies theirselves also enlarge at the same proportion, new matter continuously generates inside celestial bodies or galaxies. Some conserved laws, such as energy conserved law, angular momentum conserved law and moment conserved law, are the approximation of small time and small scope, and in big time and big scope they are no longer strictly valid. The earthquakes and the drift phenomenon of continents are exactly the performance of the earth is growing up, and new matter namely energy constantly generates and accumulates within celestial bodies including the earth all the time..."

I'm not a physicist so it isn't my job to cast judgments on stuff like this. But I do get to decide what I personally find plausible. And this just sounds crankish to me. I'd assign it a low credibility weight for purposes of my own thinking.

Yes this taking on of the whole of geophysics - quite apart from astrophysics - is what I highlighted as so bonkers in post 2.

 

[heyuhua]

Here we have it. HuHee's A mystical conviction in a cyclic universe trumps observation evidence. It MUST be contracting because the cyclic universe idea is true, you see.

 

[heyuhua]

I suggest you re-read its abstract: you've missed the point of the paper.


Who is this "we"?


False; that statement is in direct contradiction with your own supplied paper.


Irrelevant; indirect observation is still observation.


But let's say I grant you this point. Then what? Your supplied paper is then just as wrong as any other. You've just argued we (currently) cannot know whether the expansion is accelerating, in direct contradiction to what you've stated in this thread. You've just sunk your own argument!

you didn't, at all, read the presented articles :“Modification of Field Equation and Return of Continuous Creation - Galaxies Form from Gradual Growth Instead of Gather of Existent Matter”, "Correction of standard model in view of improved gravity equation”, “Modification of gravitational field equation and rational solution to cosmological puzzle” , if you really understand these articles you will have no doubt to the decelerated expansion and believe that universal expansion and contraction are cyclic, and matter is indeed creating continuously and the singularity both density and pressure were infinite didn't exist, and big bangs numerously happened in the past with density and pressure constant and still will go on in the future

 

[NotEinstein]

you didn't, at all, read the presented articles :“Modification of Field Equation and Return of Continuous Creation - Galaxies Form from Gradual Growth Instead of Gather of Existent Matter”, "Correction of standard model in view of improved gravity equation”, “Modification of gravitational field equation and rational solution to cosmological puzzle” ,

None of those articles refer to the one I linked to, so they are most likely irrelevant to this part of the discussion. I'm not going to read three articles spanning about 50 pages when they aren't relevant.

if you really understand these articles you will have no doubt to the decelerated expansion and believe that universal expansion and contraction are cyclic, and matter is indeed creating continuously and the singularity both density and pressure were infinite didn't exist, and big bangs numerously happened in the past with density and pressure constant and still will go on in the future

Then post or refer to the relevant sections here. Specifically, the parts that address and refute the paper I linked to.

 

[NotEinstein]

But let's take a look at the first few pages of "Modification of Field Equation and Return of Continuous Creation" anyway. (I'm not going to comment on the sometimes broken English.)

The introduction is mixing up cosmology and general relativity. For example, it says that inflation is a GR thing; it is not, it's a cosmology thing. Disproving inflation doesn't impact the validity of GR.
The introduction calls the existence of dark matter a problem. That's plainly false: https://en.wikipedia.org/wiki/Dark_matter#Observational_evidence
The introduction mentions the problem of the formation of stars and galaxies, without specifying what that problem is.
"In fact, as verification or test to theory cosmological results should reflect the geological appearance on the earth and on the other hand the research to the earth can not disregard cosmological development, for natural world is unified in essence." This disregards the reasoning behind the separating of these fields in science. According to existing scientific models, the two don't influence each other, so the separation is warranted. Of course, if evidence to the contrary is produced, science will have to treat them as one, but until this evidence is found, there is no reason to demand these to be treated as one. Although, admittedly, the very next sentence states: "A sharp instance is that observations show indisputably the earth is expanding but so important phenomenon can not yet obtain due explanation from cosmology or astrophysics until today ...", so I guess we'll get to the evidence for this in this paper. Seems weird to chastise science for doing the right thing (not complicating things without reason), though.
"Besides, there are also some logical confusions, for example on one hand say universal temperature descends all the time after big bang and on another hand say the sun is burning more and more brightly, its temperature is becoming higher and higher." This is of course a laughable logical mistake made by the author: a global temperature drop doesn't mean locally the temperature can't increase. I point to global warming and entropy as two other examples of this.

Section 1.1
"where γ is the coupling coefficient" Note that this gamma isn't the Lorentz factor. The version of the EFE used here is also mentioned here: https://en.wikipedia.org/wiki/Einstein_field_equations#Equivalent_formulations Under: "For example, in D = 4 dimensions this reduces to"
The expression given for the stress-energy tensor is for a perfect fluid in thermodynamic equilibrium. In other words, this isn't its general form; we are deriving things for a special case.
In the following bog-standard derivation, the metric is taken to be Minkowski with only small perturbations. Higher order terms are ignored.
Equation 1.2 assumes a harmonic condition for the perturbations.
Then, a static case is assumed, followed by the enforcing of particular behavior of the metric at long range (= far away from any source). This thus means we're in a situation where there's a (cluster of?) bubble(s) of perfect fluid, statically, in thermodynamic equilibrium, surrounded by a vacuum. I'm not sure that's even possible? How would the outer layers of this fluid stay in place? But if everything is static, then what use is this universe anyway? The kinetic mass of a moving particle is given. But we have no particles; we have a perfect fluid. ... Are those alarmbells I'm hearing? ... At this point, gamma needs to be defined differently from the standard. ... Yep, definitely alarmbells.

heyuhua: Please explain how you can meaningfully talk about a particle when all you've got is a perfect fluid. Please explain how a particle can be in motion, if the universe is static.

 

[NotEinstein]

Oh, and by the way, for any readers vaguely interested: that change in gamma is indeed the modification. In other words, Jian Liang Yang proposes to change the EFE from:
$$R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}=-8\pi GT_{\mu\nu}$$
to:

$$R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}=4\pi GT_{\mu\nu}$$

Yes, the sign is now flipped. I think that can safely be summarized as: gravity is now repulsive. It's the invention of anti-gravity!​

 

[Q-reeus]

Oh, and by the way, for any readers vaguely interested: that change in gamma is indeed the modification. In other words, Jian Liang Yang proposes to change the EFE from:
$$R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}=-8\pi GT_{\mu\nu}$$
to:

$$R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}=4\pi GT_{\mu\nu}$$

Yes, the sign is now flipped. I think that can safely be summarized as: gravity is now repulsive. It's the invention of anti-gravity!​

I have no interest in reading through the OP's 'theory', but noticed your signs for standard vs 'modified' RHS of EFE's. Surely it's the reverse, with standard form positive as given here:
https://en.wikipedia.org/wiki/Einstein_field_equations#Mathematical_form

PS: Just noticed there is a sign convention ambiguity which I was not previously aware of:
https://en.wikipedia.org/wiki/Einstein_field_equations#Sign_convention
Evidently a carry over from the +--- vs -+++ sign convention in Minkowski metric.

 

[heyuhua]

None of those articles refer to the one I linked to, so they are most likely irrelevant to this part of the discussion. I'm not going to read three articles spanning about 50 pages when they aren't relevant.


Then post or refer to the relevant sections here. Specifically, the parts that address and refute the paper I linked to.

Now I doubt that you do not know where the conclusion of accelerated expansion come, if you know this your problems will not exist

 

[exchemist]

post deleted

 

[heyuhua]

Oh, and by the way, for any readers vaguely interested: that change in gamma is indeed the modification. In other words, Jian Liang Yang proposes to change the EFE from:
$$R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}=-8\pi GT_{\mu\nu}$$
to:

$$R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}=4\pi GT_{\mu\nu}$$

Yes, the sign is now flipped. I think that can safely be summarized as: gravity is now repulsive. It's the invention of anti-gravity!​

you are taking a error, in fact it doesn't represent the gravity becomes repulsive that the sign is positive or negative, the important thing is the behavior of geodesic equation, which is decided by metric, the new metric derived out of the modified field equation still makes sure gravity, and about the details you may see Yang's articles

 

[NotEinstein]

I have no interest in reading through the OP's 'theory', but noticed your signs for standard vs 'modified' RHS of EFE's. Surely it's the reverse, with standard form positive as given here:
https://en.wikipedia.org/wiki/Einstein_field_equations#Mathematical_form

PS: Just noticed there is a sign convention ambiguity which I was not previously aware of:
https://en.wikipedia.org/wiki/Einstein_field_equations#Sign_convention
Evidently a carry over from the +--- vs -+++ sign convention in Minkowski metric.

Yang uses the -+++ convention in the paper. This is mentioned explicitly (page 6), and the given expression of the EFE in the paper confirms this (eq 1.1). The flipping of the sign is explicitly mentioned as well (near the bottom of page 7). In other words, there’s no sleight of hand being done here with sign conventions: the sign truly flips with respect to the standard EFE in Yang's paper.

Now I doubt that you do not know where the conclusion of accelerated expansion come, if you know this your problems will not exist

So you cannot point to something addressing the paper I posted, and thus cannot refute it, which means the paper you posted is countered.

you are taking a error,

This is a literal copy-paste from your own paper; any mistake made is yours.

in fact it doesn't represent the gravity becomes repulsive that the sign is positive or negative,

Well, it effectively inverts the contribution of the stress-energy tensor on the curvature of spacetime. How else am I supposed to interpret that?

the important thing is the behavior of geodesic equation,

No, the most important thing is that it needs to match reality. A flipped sign (and a factor 2) surely would have been noticed by now!

which is decided by metric, the new metric derived out of the modified field equation still makes sure gravity, and about the details you may see Yang's articles

You can't modify the EFE and modify the metric to counteract the change (if that even works), and then call your equation different. If it's just convention/notational changes, you haven't done anything new. No, Yang's claim that the sign flips is exactly that: a claim that the standard EFE is off by a minus-sign and a factor 2. It inverts the contribution of the stress-energy tensor to the curvature, no matter what tricks you apply to the metric.

Obviously Yang's claims have been experimentally falsified. While the EFE as it stands today might not be the end-all solution, clearly dropping in a minus-sign and a factor of 2 is not a viable modification.

 

[heyuhua]

you will not understand some of the subtleties of the original Yang's articles if you don't have an open mind to learn, your comments are childishly simplistic.

 

[heyuhua]

Yang uses the -+++ convention in the paper. This is mentioned explicitly (page 6), and the given expression of the EFE in the paper confirms this (eq 1.1). The flipping of the sign is explicitly mentioned as well (near the bottom of page 7). In other words, there’s no sleight of hand being done here with sign conventions: the sign truly flips with respect to the standard EFE in Yang's paper.


So you cannot point to something addressing the paper I posted, and thus cannot refute it, which means the paper you posted is countered.


This is a literal copy-paste from your own paper; any mistake made is yours.


Well, it effectively inverts the contribution of the stress-energy tensor on the curvature of spacetime. How else am I supposed to interpret that?


No, the most important thing is that it needs to match reality. A flipped sign (and a factor 2) surely would have been noticed by now!


You can't modify the EFE and modify the metric to counteract the change (if that even works), and then call your equation different. If it's just convention/notational changes, you haven't done anything new. No, Yang's claim that the sign flips is exactly that: a claim that the standard EFE is off by a minus-sign and a factor 2. It inverts the contribution of the stress-energy tensor to the curvature, no matter what tricks you apply to the metric.

Obviously Yang's claims have been experimentally falsified. While the EFE as it stands today might not be the end-all solution, clearly dropping in a minus-sign and a factor of 2 is not a viable modification.

I am sure that you aren't familiar with the calculating details of general relativity, in fact, it doesn't decide force's behavior directly whether the sign is positive or negative, because only the metric get into the geodesic equations which decide the behavior of force. It is worthwhile to note that now pressur takes negative but not previous zero or positive, the negative pressure changes the space-space components of metric and doesn't change time-time component.
you will not understand some of the subtleties of the original Yang's articles if you don't have an open mind to learn, your comments are childishly simplistic. In a word, to understand Yang's opinion you must be familiar with the calculating details of general relativity,

 

[Michael 345]

Do any of the previous post indicate gravity is no longer a attraction force but a repulsion force?

Is it safe to go outside while you lot are debating this?

 

[Xelasnave.1947]

Do any of the previous post indicate gravity is no longer a attraction force but a repulsion force?

General Relativity does not treat gravity as a force but as an alteration in space time.

General Relativity is a model and of course another model can treat it differently ... its just that there are no models that come close to replacing General Relativity.
Alex

 

[Michael 345]

General Relativity does not treat gravity as a force but as an alteration in space time.

General Relativity is a model and of course another model can treat it differently ... its just that there are no models that come close to replacing General Relativity.
Alex

I don't care how it's treated - CAN I GO OUTSIDE?

 

[NotEinstein]

you will not understand some of the subtleties of the original Yang's articles if you don't have an open mind to learn, your comments are childishly simplistic.

I'm childishly simplistic (by the way, please don't insult people), but you can't even explain the kind of universe this EFE is supposed to be valid for? I'm childishly simplistic, but you can't even explain what the flipping of the sign means. I'm childishly simplistic, but you apparently don't consider it important to check whether a hypothesis matches reality.

Well, one of us two indeed is.

I don't care how it's treated - CAN I GO OUTSIDE?

Yes, it's safe (well, safe gravity-wise...). Reality doesn't conform to some arbitrary hypothesis; it's the goal of science to conform to reality. So somebody inverting gravity on paper is perfectly harmless.

 

[Michael 345]

So somebody inverting gravity on paper is perfectly harmless

Phew

 

[heyuhua]

I'm childishly simplistic (by the way, please don't insult people), but you can't even explain the kind of universe this EFE is supposed to be valid for? I'm childishly simplistic, but you can't even explain what the flipping of the sign means. I'm childishly simplistic, but you apparently don't consider it important to check whether a hypothesis matches reality.

Well, one of us two indeed is.


Yes, it's safe (well, safe gravity-wise...). Reality doesn't conform to some arbitrary hypothesis; it's the goal of science to conform to reality. So somebody inverting gravity on paper is perfectly harmless.

It is obviously wrong to think the sign to decide attraction or repulsive , your perspective indicates you didn't go deep into calculating details, you should know field equation is the equation that decides metric components and doesn't represent attraction or repulsive, it is the geodesic equation that give expression to attraction or repulsive. I sharply tell you that Yang's new theory matches well reality, hope you be humble enough to learn from Yang's theory