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this post was submitted on 15 Jul 2023
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Ok, so I got the paper from its original author after emailing him about it (who even thanked me for the interest in his work, I freaking love scientists). And while there’s a lot of math, half of which I’m not even remotely qualified to understand, here’s what I got from it:
First, the paper is quite broad and compares 6 different models, plain LCDM (vacuum has energy that’s constant throughout the universe, it drives the expansion, cosmological constant is constant), CCC (“covarying coupling constants”: cosmological constant isn’t constant and may change over time and space, and dark energy might be more of a field than a property of space), their hybrids with Tired Light, and Tired Light alone. There’s some more discussion about these models below, in case you’re interested.
Btw, Tired Light hypothesis suggests that there’s no expansion, light just loses energy as it travels though space and that’s what gets interpreted as red shift. It’s not widely accepted and is not really considered viable, as far as I know.
Here’s an important to this whole discussion part: proposed age increase comes only from hybrid models (since there wouldn’t be any change in LCDM, and in TL age of the universe kinda makes no sense — no expansion and all that).
So what the author has found is that the best model to explain those weird redshift observations from JWST is the hybrid CCC+TL model, which assumes both “cosmological constant isn’t constant” and “tired light is a thing”. And that combination seems highly unlikely.
So the universe probably isn’t 26+ bn years. It’s a stepping stone towards finding a better model.
To what are you referring when you say “those weird JWST red shift observations”? I’d be curious to read more about that specifically.
It’s about this — JWST found unusually bright early galaxies that already existed at around 350 mln years after the Big Bang, which is extremely early for such structures to exist. It implies that they should have started forming at around ~100 mln years, which is wa-ay earlier than previously thought. So CCC+TL is a model that tries to fit observed data, but it’s not the only proposed solution (and it’s quite convoluted due to including Tired Light).
You can google more about that using terms like JWST + early galaxies, high redshift galaxies, population III stars (refers to metallicity and goes “backwards”, Sun is a population I star).
In another paper on the arxiv, the author uses time-varying fundamental constants (c, h, k~B~) and relates them to a time-dependent Newton coupling, and calls this "varying coupling constants". Can you say whether the author also has time-varying fundamental constants in this paper, or only a time-varying cosmological constant? The language in the abstract makes it sound like multiple "coupling constants", but you only mention Λ, if I'm not missing anything.
Covarying coupling constants is an established name, so it’s used as is. But the paper only mentions lambda, as far as I remember. There might be something else used in the equations, I haven’t delved deep into those, but nothing else should really be required for this particular discussion.