Undergrad Postulating a minimum gravitational field strength

[kodama]

TL;DR

postulating a minimum gravitational field strength postulating a minimum gravitational field strength (minimum curvature) and a minimum acceleration

this paper postulating a minimum gravitational field strength postulating a minimum gravitational field strength (minimum curvature) and a minimum acceleration but otherwise leaving Gr could reproduce MOND

[Submitted on 25 May 2022]

MONG: An extension to galaxy clusters​

Louise Rebecca (1,2), Arun Kenath (2), C Sivaram (3) ((1) Department of Physics, Christ Junior College, (2) Department of Physics and Electronics, CHRIST (Deemed to be University), (3) Indian Institute of Astrophysics)

The presence of dark matter, though well established by indirect evidence, is yet to be observed directly. Various dark matter detection experiments running for several years have yielded no positive results. In view of these negative results, we had earlier proposed alternate models by postulating a minimum gravitational field strength (minimum curvature) and a minimum acceleration. These postulates led to the modified Newtonian dynamics and modified Newtonian gravity (MONG). The observed flat rotation curves of galaxies were also accounted for through these postulates. Here we extend these postulates to galaxy clusters and model the dynamical velocity-distance curve for a typical cluster such as the Virgo cluster. The radial velocities of galaxies in the Virgo cluster are also obtained through this model. Observations show an inconsistency in the Hubble flow at a mean cluster distance of 17 Mpc, which is expected in regions of high matter density. This decrease in velocity is predicted by our model of modified gravity (MONG). The radial velocity versus distance relation for galaxies in the Virgo cluster obtained using MONG is in agreement with observations.

Comments:	9 pages, 2 figures, 21 equations
Subjects:	General Relativity and Quantum Cosmology (gr-qc)
Cite as:	arXiv:2205.12793 [gr-qc]

 

[Vanadium 50]

Yawnmaking. Here's their "evidence".

 

[kodama]

what is yawning their "evidence".

 

[Delta2]

Yes @Vanadium 50 I think you should "elaborate" more on what you find yawnmaking. If you going to use the argument that you were already bored and that paper made you bored even more so you are bored to explain, then ok ...

 

[fresh_42]

We will discuss it once it will be published.

Thread closed.

 

[fresh_42]

I have been told that it has been published in
https://www.worldscientific.com/worldscinet/mpla
https://www.worldscientific.com/doi/10.1142/S021773232250078X

I will therefore re-open the thread. Btw., this citation should have been given by the OP! Arxiv.org is not sufficient for problematic papers like that one.

However, I want to add that the publisher is not one of the established physics journals. For details see
https://www.resurchify.com/impact/details/29052

 

[kimbyd]

Wake me up when they've run a simulation of the CMB temperature power spectrum using their model.

 

[Vanadium 50]

World Scientific is real, albeit not high on the prestige list: impact factor of the journal in question is a whopping 1.5.

But does anyone seriously think the best fit to the data points is the curve I posted? With the dipsy-do in the midle?

 

[kodama]

page 3
they add both gravitational self-energy and dark energy to the poison equation to give rise to a MOND like physics

the gravitational self-energy add cosmological constant with reference 5-7 could reproduce many MOND like physics.

is this plausible

 

[kimbyd]

World Scientific is real, albeit not high on the prestige list: impact factor of the journal in question is a whopping 1.5.

But does anyone seriously think the best fit to the data points is the curve I posted? With the dipsy-do in the midle?

Maybe not, but it's not necessarily out of bounds for the model, and it enhances the model's falsifiability. Still, like I said, I don't have much interest in modified gravity models until they look at the CMB data, precisely because it's hard to explain the CMB with anything but dark matter and dark energy.

 

[Vanadium 50]

Well, this shouldn't degenerate into a MOND thread, where the usual suspects will say the usual things. I will make three comments and then shut up.

1. A minimum gravitational field strength is exactly the same as a minimum gravitational acceleration. At best, this paper is playing with the functional form.
2. MOND did correctly prediect the 1st to 2nd peak ratio in the CMB. (McGaugh, 1999). So far as I know, this is the only correct prediction made by MOND in other-than-galactic scales.
3. The dipsy-do in the middle of the curve is absurd.

 

[kimbyd]

Well, this shouldn't degenerate into a MOND thread, where the usual suspects will say the usual thing. I will make three comments and then shut up.

1. A minimum gravitational field strength is exactly the same as a minimum gravitational acceleration. At best, this paper is playing with the functional form.
2. MOND did correctly prediect the 1st to 2nd peak ratio in the CMB. (McGaugh, 1999). So far as I know, this is the only correct prediction made by MOND in other-than-galactic scales.
3. The dipsy-do in the middle of the curve is absurd.

The ratio of the first and second peaks in the CMB is uninteresting, as it can be explained by simply having a different baryonic matter density. It's the relationship between the first/second peak ratio and the second/third peak ratio that is the critical signal of dark matter in the CMB. Judging based upon the first and second peaks is rather like judging a 500-lap race from the winner of the first lap. Even though it's only one additional peak, the difference in explanatory power really is that stark.

Now, with the Planck data, even more peaks are measured to a very high degree of accuracy (I count seven peaks clearly visible in their power spectrum). Any competing model must accurately recreate the entire spectrum to be worth investigating further. That's a tall ask. But we have this very detailed data set that is extremely sensitive to dark matter density. Failing to take advantage of it when pursuing an alternative to dark matter is deeply suspicious.

This can be frustrating, because actually calculating the power spectrum from an alternative gravity model can be a difficult thing to do. But it really needs to be done. And the first two peaks alone don't cut it.