Did scientists just find that the Universe has finite angular momentum?

[pines-demon]

I have seen a lot of popular hype concerning the recent publication of:

• Shamir, The distribution of galaxy rotation in JWST Advanced Deep Extragalactic Survey, Monthly Notices of the Royal Astronomical Society, 538 (2025), Pages 76–91

The article seems to show that most galaxies (about 2/3) observed by the James Webb telescope rotate in the opposite direction to our Milky Way. This has taken weird interpretations like: "I think that the simplest explanation of the rotating universe is the universe was born in a rotating black hole" (by the author himself!). But my problem is that I don't get the reason behind the hype or implications of this publication.

I want to understand what is so weird in this observation. I get the idea that "in average scientists would expect to find 50% of galaxies rotating one way, while the other 50% rotate the other way" but that is not what physics says, for me the important thing is that angular momentum is conserved, right? So counting the signs of the galaxies can be misleading isn't? You would have to know how heavy the galaxies are and how fast the galaxies are rotating to calculate their angular momentum. Maybe somebody with more patience can verify if that is in the article (I could not find it).

 

[Bandersnatch]

This was briefly discussed before in another thread.
Yours is a good point. What made me roll my eyes, though, was the sample size from which these grandiose claims are derived.

 

[pines-demon]

This was briefly discussed before in another thread.
Yours is a good point. What made me roll my eyes, though, was the sample size from which these grandiose claims are derived.

Oops I missed the other thread, do you have a link?

 

[Bandersnatch]

https://www.physicsforums.com/threads/an-old-spin-to-our-universe.1079169/
There wasn't much of a discussion there anyway.

 

[pines-demon]

https://www.physicsforums.com/threads/an-old-spin-to-our-universe.1079169/
There wasn't much of a discussion there anyway.

Wow I did not notice how bad the sigma was. Also only galaxies close-by...

 

[Bandersnatch]

Yeah. Takes a bit more to make my universe spin.

 

[Ken G]

I'm not sure where this number that 2/3 rotate the opposite way comes from, in the article it says: "Of these galaxies, 105 rotate counterclockwise, while 158 rotate clockwise." So that looks like 3/5 not 2/3. They claim that the probability of flipping 263 coins and getting 158 heads is 0.0007, so that's the basis of their claim. I think they forget to double that number, because one should not just test the probability that the spins are opposite the Milky Way spin, but also the probability that they are the same as the Milky Way, because the author would of course have made the same argument either way. So then it's really 0.0014, which is still quite small I admit. But can we really trust the analysis? The paper includes an awful lot of self-references for my taste, and also a lot of speculation about what might be the cause of this imbalance, which I do not think strengthens the paper but obviously the referee felt it was at least worth getting out there.

 

[Bonkers]

The idea that the universe has an overall angular momentum is possibly worth exploring further though - it could be a form of MOND that might account for dark matter/energy?
We excuse the fact that inflation does not conserve energy, and that it expands faster than light, why not add that it doesn't conserve angular momentum? The rules for the creation of spacetime are not the same as the rules within it.

 

[weirdoguy]

We excuse the fact that inflation does not conserve energy

We don't "excuse" it, it comes directly from the math of GR, and problems with global notion of energy in non-stationary spacetimes.

why not add that it doesn't conserve angular momentum?

Does it come from the math?

 

[Bonkers]

Thanks WG, I see that you've made many comments with good approval.
I'm not attempting to put out a paper, this is a forum, for ideas not proofs.
The "does it come from the math" is a bit blithe, dismissive even.
There are dozens of inflation theories, each with a parameter space in a minimum of two variables, as Wikipedia has it. These theories struggle with energy and entropy creation, both - and I don't see any simple linkage to GR, to explain energy creation in superluminal expansions.
Any notion that my suggestion has proofs that just "drop out" of the math, or maths as we call it, is optimistic.
For starters, most if not all inflation theories don't consider rotation - how can an entire universe frame rotate? - with respect to what? I propose that maybe it can, with respect to itself, and this would be evidenced by large-scale dynamics (MOND), galactic rotation-bias, and/or other means.

In a related matter, what happens to the angular momentum of a black hole? - they all spin, everything does, but with zero dimension, where does it go?

If there is a relationship between black holes that vanish energy from our universe, to inflation that creates energy in newly-spawned universes, might this need to be extended to cover non-zero AM?

FWIW I am a graduate Physicist, BSc(hons) but not cosmology or string-theory grade.

 

[weirdoguy]

In a related matter, what happens to the angular momentum of a black hole? - they all spin, everything does, but with zero dimension, where does it go?

You're lucky - there is a thread on this very topic in Astronomy subforum.

The "does it come from the math" is a bit blithe, dismissive even.

No. Do you understand what is the definition of energy in GR? What conditions need to be met for it to be conserved globaly?

 

[gmax137]

We don't "excuse" it, it comes directly from the math of GR, and problems with global notion of energy in non-stationary spacetimes.

I'm a complete amateur here - is this saying that an evolving universe lacking time symmetry does not conserve energy? Since energy conservation is a consequence of time symmetry via Noether's theorem?

 

[weirdoguy]

Yes, here's a nice article:

https://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/