Latest on MOND

[Markus Hanke]

Looks like the air might be getting a bit thin for MOND:

https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stad3393/7342478?login=false

[TheVat]

In their analysis, levels of confidence with sigma up in the teens. If sigma there means what it does in other fields, that's quite high confidence in Newtonian dynamics versus MOND. Damn. I was sort of rooting for MOND, given that it would upset the apple cart of dark matter.

From the chat on MOND over at sciforums, which Pinball started last week, it sounds like there will be hard scrutiny of the data quality.

[Markus Hanke]

1 hour ago, TheVat said:

From the chat on MOND over at sciforums, which Pinball started last week, it sounds like there will be hard scrutiny of the data quality.

As it should be, of course  

This doesn’t actually rule out MOND, it just means that even if MOND holds true, you still need dark matter to fit all observational data, though presumably in lesser quantities.

[exchemist]

1 hour ago, Markus Hanke said:

As it should be, of course  

This doesn’t actually rule out MOND, it just means that even if MOND holds true, you still need dark matter to fit all observational data, though presumably in lesser quantities.

Which knackers the whole idea of MOND though, doesn’t it?

[Markus Hanke]

11 hours ago, exchemist said:

Which knackers the whole idea of MOND though, doesn’t it?

Yes, definitely. But I think I was actually wrong in my comment - upon closer inspection, it really does seem to rule out MOND altogether. Subject to further verification, of course.

[MSC]

On 11/16/2023 at 10:43 AM, Markus Hanke said:

As it should be, of course  

This doesn’t actually rule out MOND, it just means that even if MOND holds true, you still need dark matter to fit all observational data, though presumably in lesser quantities.

No necessarily. In fact other research may have thrown doubt onto dark matter too, at least there are theories that explain observational data without invoking dark matter. 

Quote

This discovery challenges the conventional understanding that dark matter constitutes approximately 27% of the universe, with ordinary matter making up less than 5% and the rest being dark energy, while also redefining our perspective on the age and expansion of the universe.

“The study’s findings confirm our previous work, which suggested that the universe is 26.7 billion years old, negating the necessity for dark matter’s existence,” Gupta explains.

“Contrary to standard cosmological theories where the accelerated expansion of the universe is attributed to dark energy, our findings indicate that this expansion is due to the weakening forces of nature, not dark energy,” he continued.

https://www.earth.com/news/dark-matter-does-not-exist-universe-27-billion-years-old-study/

By integrating covarying coupling constants with tired light theory, and a new 27billion year age of the universe, then why would the universe need dark matter?

It's been a long time since the existence of dark matter was theoriesed and other than indirect gravitational effects, there is no other evidence for it. Which to me still means we've gotten something wrong about gravity. 

[MSC]

Fyi not saying I believe the above, just that I put as much faith in it as I do the standard model due to the fact that I fully grasp neither and the fact that the standard model doesn't explain everything. I can't honestly say with any reasonable certainty that I know any theory that explains everything in physics.

[swansont]

3 hours ago, MSC said:

No necessarily. In fact other research may have thrown doubt onto dark matter too, at least there are theories that explain observational data without invoking dark matter. 

https://www.earth.com/news/dark-matter-does-not-exist-universe-27-billion-years-old-study/

By integrating covarying coupling constants with tired light theory, and a new 27billion year age of the universe, then why would the universe need dark matter?

It's been a long time since the existence of dark matter was theoriesed and other than indirect gravitational effects, there is no other evidence for it. Which to me still means we've gotten something wrong about gravity. 

It’s not a “discovery” as such. It’s a model based on tired light and varying fundamental constants, without the experimental support one needs to support those ideas. Not a good foundation for a model. The tone of the article suggests that this is somehow a credible experimental result, when it is very far from that.

[MSC]

34 minutes ago, swansont said:

It’s not a “discovery” as such. It’s a model based on tired light and varying fundamental constants, without the experimental support one needs to support those ideas. Not a good foundation for a model. The tone of the article suggests that this is somehow a credible experimental result, when it is very far from that.

Thanks for clearing that up, my pinch of salt was justified it seems. 

[MigL]

As the accurate measurement of the speed of gravitational waves, 5 years ago, ruled out any Modified Newtonian Dynamics theories that also require Dark Matter, and these results rule out MOND theories that don't require the addition of Dark Matter effects, I would think the last nail has been driven into the coffin of M Milgrom's theory.

[J.C.MacSwell]

It's just a flesh wound!