James Webb Space Telescope finds evidence for alternate theory of gravity

My hangup with MOND is still general relativity. We know for a fact that gravity is _not_ Newtonian, that the inverse square law does not hold. Any model of gravity based on an inverse law is simply wrong.

Another comment linked to https://tritonstation.com/new-blog-page/, which is an excellent read. It makes the case that GR has never been tested at low accelerations, that is might be wrong. But we know for a fact MOND is wrong at high accelerations. Unless your theory can cover both, I don't see how it can be pitched as an improvement to GR.

Edit: this sounds a bit hostile. to be clear, I think modified gravity is absolutely worth researching. but it isn't a silver bullet

>We know for a fact that gravity is _not_ Newtonian, that the inverse square law does not hold

[citation needed]

The consensus is that gravity - outside of extreme mass/energy environments - works just as Newton described it to many many decimal places.

Emphasized part added because people in the replies thought that I literally think that General Relativity is somehow wrong. Don't be dense. All I'm saying is that gravity at galactic scales works as Newton described it. General Relativity has extremely tiny effect at those scales.

You're simply wrong. There's no other way to put it. The GPS system would have been simply impossible to deploy without the general theory of relativity. There's no extreme energy or mass involved, just precision requirements that are influenced by the minuscule differences in time experienced by the surface of the earth and orbiting satellites.

Also Newton's laws famously could not account for Mercury's orbit. Mercury is just an ordinary planet orbiting an ordinary star. Nothing extreme is involved. He knew his laws were incomplete. But they were so dead-on in basically every other scenario that could be physically observed at the time that he figured there was some small tweak missing (or maybe another planetary body that hadn't been spotted yet).

Easy there champ. Noone is shitting on general relativity.

All I'm saying is that the effect of general relativity at galactic scales is so minuscule, that galactic dynamics is - for all intents and purposes - governed by the Newtonian limit of gravity.

If you propose that gravity doesn't behave like the Newtonian limit at those scales, then you're contradicting general relativity as well, since the far-field limit of the Schwartzschild metric is literally Newton's inverse square law.

In layman terms, modified Newtonian gravity, that the article talks about, is an attempt to explain why galaxies don't rotate the way they should according to Newton (and Einstein, because at those distances the two are the same!!!).

We already know that one must not use Newtonian gravity on the galaxy scale. For example, properly accounting for GR effects is enough to explain the observed rotational curve for our Galaxy without the need for any dark matter hypothesis.

Similarly there are papers that tries to explain the effects attributed to dark matter on the scale of tenths and hundreds megaparsecs using just proper accounting of GR effects. They are rather speculative, but still they show that even on very huge distances Newtonian approximation may not be valid.