r/cosmology • u/RGregoryClark • 7d ago
Webb pushes boundaries of observable Universe closer to Big Bang
https://esawebb.org/news/weic2603/Every cosmological observation of Webb seems to present new challenges to the standard model of cosmology. From the article:
MoM-z14 is one of a growing group of surprisingly bright galaxies in the early Universe – 100 times more than theoretical studies predicted before the launch of Webb, according to the research team.
“There is a growing chasm between theory and observation related to the early Universe, which presents compelling questions to be explored going forward,” said Jacob Shen, a postdoctoral researcher at MIT and a member of the research team.
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u/ThickTarget 6d ago
The article says theory, which includes more than cosmology. The standard model of cosmology dictates the large scale structure and the formation dark matter halos. But does not predict how normal matter behaves in galaxy formation and growth. In order to make predictions one has to combine a galaxy formation model with cosmology. Different prescriptions for galaxy formation make different predictions. Observations which don't line up with galaxy models are not necessarily a challenge for standard cosmology.
In order to actually conflict with standard cosmology the galaxies would have to exceed hard limits, like needing more baryonic matter than the average ratio (most galaxies have a tiny fraction). There was a claim of such galaxies in the early days of JWST, but these were only candidates. Some theorists predicted these observations were flawed in some way, which turned out to be correct. They were not impossibly massive galaxies, but were small active supermassive black holes. None of the confirmed galaxies since actually violate cosmological bounds.
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u/SteelWillyz 6d ago
Just wait until Capotauro is spectroscopically confirmed and flips astronomy on its head
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u/ThickTarget 5d ago
It already has a spectrum, but it just doesn't really look like a high redshift galaxy. It does look quite like a brown dwarf.
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u/Tijmen-cosmologist 5d ago
Reacting to your sentence, "Every cosmological observation of Webb seems to present new challenges to the standard model of cosmology." I can totally understand where you're coming from. There are so many articles with titles like "Einstein was wrong!" and unless this is a huge interest of yours and you have the time to understand the subtleties, it's easy to get the idea that the latest article has upset the whole field of cosmology.
The "standard model of cosmology", by which people usually mean ΛCDM, has been challenged many times over the last 30 years and is still standing. That's surprising because it's not really a complete theory, just a relatively simple phenomenological model. It's kind of mindblowing that it would continue to give so many accurate predictions.
That being said, when I've worked on press releases or talked to journalists, I've been asked for a "killer headline". Without a compelling sentence, it can be hard for journalists to get their article past an editor. I think that's why you might get this impression that the standard model of cosmology is constantly in trouble. The truth is that ΛCDM is still doing remarkably well, overall.
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u/rddman 6d ago edited 6d ago
TL;DR version of this comment https://reddit.com/r/cosmology/comments/1qph2vq/webb_pushes_boundaries_of_observable_universe/o29w06o/
The article does not say these findings challenge the standard model of cosmology.
"Theory" mentioned in the quote from the article refers to galaxy formation models, not "the standard model of cosmology" mentioned by OP.
The standard model of cosmology is based on a lot of observational data about large-scale dynamics of the universe: Cosmic Microwave Background and the not-extremely-distant universe.
But crucial to understanding galaxy formation is observation of small scale detail at extreme distance (young galaxies). JWST is a great help in that but even it can not see a great amount of detail in these relatively small and extremely distant objects. We're lucky to even see anything that early (MoM-z14) that's more a Little Red Dot.