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James Webb Space Telescope finds evidence for alternate theory of gravity

(thedebrief.org)
355 points jchanimal | 4 comments | 16 Nov 24 18:33 UTC | HN request time: 0.686s | source
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astroH ◴[16 Nov 24 21:52 UTC] No.42159672[source]▶
In my opinion, this article is misleading at best. "...scans of ancient galaxies gathered by the JWST seem to contradict the commonly accepted predictions of the most widely accepted Cold Dark Matter theory, Lambda-CDM." --> LCDM doesn't predict what galaxies should look like, it simply predicts how much mass is in collapsed structures and that dark matter haloes grow hierarchically. In contrast, with JWST we see light and need to infer what the underlying properties of the system are. It was shown very early on that the theoretical upper limit (i.e. taking all of the gas that is available in collapsed structures and turning it into stars) predicts a luminosity function (i.e. number of galaxies per unit luminosity) that is orders of above what JWST has observed (e.g. https://ui.adsabs.harvard.edu/abs/2023MNRAS.521..497M/abstra...). This means that there is plenty of space within the context of LCDM to have bright and seemingly large and massive galaxies early on. Based on current JWST data at these early epochs, there are really no convincing arguments for or against LCDM because it's highly sensitive to the galaxy formation model that's adopted.
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1. ajross ◴[16 Nov 24 23:27 UTC] No.42160488[source]▶
> there are really no convincing arguments for or against LCDM because it's highly sensitive to the galaxy formation model that's adopted.

To be fair, that is absolutely not the way ΛCDM would have been described to someone in the pre-Webb days. It was a well-regarded theory and the hope was (a-la the Higgs detection) that new data would just better constrain the edges and get us on to the next phase of the problem.

But instead it's a wreck, and we didn't see what we were expecting at all, and so now we're retreating to "Well, ΛCDM wasn't exactly proven wrong, was it?!"

That doesn't mean it's wrong either, and it for sure doesn't mean MOND is right. But equally for sure this is a Kuhnian paradigm shift moment and I think it's important for the community to be willing to step back and entertain broader ideas.

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2. astroH ◴[16 Nov 24 23:39 UTC] No.42160566[source]▶
Again, LCDM and galaxy formation are two different things. "...and we didn't see what we were expecting at all..." It depends on who you ask. There were many pre-JWST models that did well in this regard. A particularly interesting one is this from 2018 (https://ui.adsabs.harvard.edu/abs/2018MNRAS.474.2352C/abstra...). That group even had to write another paper reminding everyone of what they predicted (https://ui.adsabs.harvard.edu/abs/2024arXiv240602672L/abstra...). Another example is here (https://ui.adsabs.harvard.edu/abs/2023OJAp....6E..47M/abstra...) which shows results from a simulation from ~2014. I can provide numerous other examples of this. My point isn't which theory is or isn't wrong, my point is that what is presented in this particular article is not a constraint on any realistic theory of gravity as the sensitivity of these particular observations to galaxy formation modeling is so strong.
3. Davidzheng ◴[17 Nov 24 00:16 UTC] No.42160792[source]▶
Absolutely not in the field, so if you are please completely disregard. But from conversations with physicists (not cosmologists) I always thought people thought a lot of evidence for ΛCDM was dubious at best.
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4. liquidpele ◴[17 Nov 24 15:39 UTC] No.42164729[source]▶
Dubious at best, lol, Isn’t that half of all of cosmology? Lots of pure math these days and little science it seems.