Please rebut the Janus Cosmological Model

[Reality Check]

Even though it's pedantic, GR did not "predict" mercury's movement as much as it "explained" it. ...

GR does predict the precession of the orbit of Mercury. That we measured this precession before GR existed does not matter - it is still a prediction of GR. GR matches the existing observations and thus explains the precession of the orbit of Mercury.

If you read the PDF you link to (The Janus Cosmological Model and the fluctuations of the CMB) than you will no fluctuations of the CMB !
Lots of assertions including his "dark matter is no longer required" ignorant assertion (galaxy rotation curves are not the only evidence for dark matter).
Only an assertion that JCM has an imprint that corresponds to the "CMB inhomogeneities". An opinion of "We think that this produces the light inhomogeneities in the CMB". Close to a lie of "We point out that such primeval gravitational instability, occurring in the negative sector, make an imprint in ours, and that corresponds to the observed fluctuations in the CMB." when nothing in the paper shows any correspondence.

Most importantly: No power spectrum of the CMB.
IF02 Cite the JCM calculation for the CMBR and its power spectrum.

[Reality Check]

...That's the core conceit of the model though; ...

Merely asserting that "the negative matter in the solar system is almost zero" (as in his PDF) is not science and does not reduce JCM to GR. I could assert that "Because positive and negative matter are repelling each other, the negative matter in any galaxy is almost zero." and thus JCM cannot explain galaxy rotation curves and be as correct as Petit !

IF04a: Cite the JCM prediction for the precession of the orbit of Mercury.
IF04b: Cite the JCM prediction for the bending of light by the Sun.
IF04c: Cite the JCM prediction for the gravitational time dilation experiments.
These questions could all be answered by
IF04z: Cite the JCM calculation that there is "almost zero" negative matter in the solar system and that is enough to reduce JCM to GR.

[Reality Check]

I think within the FRAMEWORK of a model is very different from within the ESTABLISHED HEURISTICS of a model. ...

Which is still not what you wrote in your "As far as I could tell this was an attempt to EXPLAIN what we call "black holes" as "bridges" WITHIN the framework of GR..." post as I explained: GR does not have JCM's "bridges". The closest GR gets is the speculation of wormholes but these are not JCM's assumed "bridges" (wormholes have a sound mathematical background). Thus that paper cannot be "WITHIN the framework of GR".

[Reality Check]

Idk, this, certainly looks like mathematical support to me. ...

A "Snaggy - easy screenshot" that to me is blank is not mathematical support for what is so far a fantasy of "bridges" in JCM. Thus:
IF05: Cite JCM's mathematic treatment of its "bridges in a published scientific paper.
Petit imagining what JCM "bridges" may do does not remove GR singularities or JCM singularities.

There is no empirical evidence for GR singularities and we think that cannot be any empirical evidence. Black holes have event horizons that hide any singularities. The conditions in the early universe hide any cosmological singularity. The GR singularities happen in GR and we will need a quantum gravity theory to see if they persist. Expectations are that they will not since quantum fluctuations may "blur" them out.

The evidence that black holes exist is very strong as you know: Black hole - observational evidence

[Hornblower]

That's just factually inaccurate. There are a million reasons (social, religious, economic, racial) why good ideas would get ignored. The history of science is full of these examples. In fact, how long after Copernicus before the heliocentric model was the mainstream?

In my opinion it was not being unreasonably hidebound to be slow to embrace the Copernican model. As presented it was purely kinematic and it was contrary to the long-held "common sense" view of the Earth as a large stationary platform with the heavenly bodies moving around it. If he had used the same geometric techniques as Ptolemy, his model would have been merely a vector transformation of Ptolemy's model, with identical positional results. There was not yet a dynamic theory to apply to the models to test them. That came with Newton after Kepler had cleaned up the model.

...snip...
To attack the JCM for not including a cosmological constant or for attributing the effect of dark matter to negative mass is equivalent to attacking the heliocentric model for not having epicycles!

Copernicus' heliocentric model had epicycles, lots of them. They were his way of attempting to reconcile the observations with the idea that everything in the heavens must move in constant-rate circles or combinations thereof.

I still want to defend the actual model, but if things are unclear about how the model works, you gotta ask! Attacking a misconception of the model isn't going to help. Normally I wouldn't mind explaining/repeating myself but there's a limited amount of time here.

[Shadowybeige]

In my opinion it was not being unreasonably hidebound to be slow to embrace the Copernican model. As presented it was purely kinematic and it was contrary to the long-held "common sense" view of the Earth as a large stationary platform with the heavenly bodies moving around it. If he had used the same geometric techniques as Ptolemy, his model would have been merely a vector transformation of Ptolemy's model, with identical positional results. There was not yet a dynamic theory to apply to the models to test them. That came with Newton after Kepler had cleaned up the model.Copernicus' heliocentric model had epicycles, lots of them. They were his way of attempting to reconcile the observations with the idea that everything in the heavens must move in constant-rate circles or combinations thereof.

Those are both really good points. I wasn't really trying to make hard claims there so much as illustrate via comparison. In the first instance I was trying to point out that 40 years doesn't seem like a long time. In the second instance I was more trying to illustrate how a lack of an entity is not a problem if the observations line up. I'm sure there are plenty of problems with this model, just like copernicus' epicycles. In fact, I compared it to the pre-Kepler copernican model earlier in the thread.

[Shadowybeige]

IF04z: Cite the JCM calculation that there is "almost zero" negative matter in the solar system and that is enough to reduce JCM to GR.

Hmm, that's a point I've wondered about myself. How does he determine the distribution of matter in the negative sector? I imagine its has to do with negative gravitational lensing and a lot of math based on distributions of positive matter. I'll look into it.

[Reality Check]

In the first instance I was trying to point out that 40 years doesn't seem like a long time.

It is a long time compared to GR, Shadowybeige. GR took about 10 years to be constructed basically from scratch and even made predictions while being developed. That included Einstein learning the mathematical tools that cosmologists are taught today. GR solutions appeared soon afterward, e.g. Schwarzschild solution in 1915 (black holes) and Friedmann–Lemaître–Robertson–Walker solution in 1922 (solution for a homogeneous, isotropic, expanding or contracting universe). Eddington's observation that light bent by the Sun agreed with GR was in 1919.

Contrast this to FCM where there is no sign yet that FCM makes any testable, falsifiable predictions that distinguish it from other MOND theories or Lambda-CDM.

[Shadowybeige]

I don't think anyone is denying that General Relativity and Einstein in particular were amazing.

[Reality Check]

I don't think anyone is denying that General Relativity and Einstein in particular were amazing.

No one is doing that. My point was that the mathematical tools used for GR have in existence for a century and that it took only a few years to find exact solutions for GR. We should note that GR theory was not really fully established until its "golden age" of the 60's and 70's. That was when the assumed existence of gravitational waves was put on a sound theoretical basis and black holes become established.

An enormous body of mathematics for GR is another issue for FCM. That math should make it easier to get FCM solutions. But 40 years of work and there seems no equivalent of the Friedmann–Lemaître–Robertson–Walker solution for a homogeneous, isotropic, expanding or contracting universe.

Thus: Contrast this to FCM where there is no sign yet that FCM makes any testable, falsifiable predictions that distinguish it from other MOND theories or Lambda-CDM.

[Reality Check]

How does he determine the distribution of matter in the negative sector?

Try Physical and Mathematical Consistency of the Janus Cosmological Model (JCM) (PDF) where these is a 2D large-scale simulation which places all of the negative matter in discrete clumps taken from reference 6 (a 2001 conference presentation): Twin matter against dark matter (PDF)

Not a great result and apparently still not published in a journal. The large-scale structure of the universe does not look like those simulations which give almost a honeycomb structure with positive matter cells around negative matter cores. There is also an implication that all of the negative matter is clumped in the middle of voids. But FCM needs some negative matter distributed inside and around galaxies to explain galaxy rotation curves. Plus a galaxy formation speculation. Then "5- Galaxies confined by surrounding twin matter counter-pressure" which ignores the implication that all of the negative matter is in the center of cells and has an "Ad hoc twin matter distribution, for 3d confinement".

[mkline55]

According to Jean-Marie Soureau’s dynamical group theory, the action of elements of this group on movements in space-time result in some movements which follow a time reversal; they appear to be going "backwards through time". Modern physicists use the restricted Poincarė group, limited to only orthochronous movements, and therefore ignore this issue. In group theory, however, the T operator is real and we can explore retrochronic movements. Smarter people than I have shown, (http://ayuba.fr/souriau/Souriau-time...-inversion.pdf) using maths I can only begin to understand, that when using the full Poincare group time reversal goes with mass and energy inversion. So at least the precedent for negative mass is there, determined mathematically by an independent researcher..

That's from the second paragraph of the "Foundation" section of your first post. I don't see any other references in the discussion to anything going "backwards through time." What is the relevance?