Our universe could be twice as old as current estimates, according to a new study that challenges the dominant cosmological model and sheds new light on the so-called "impossible early galaxy problem."

Our universe could be twice as old as current estimates, according to a new study that challenges the dominant cosmological model and sheds new light on the so-called “impossible early galaxy problem.”

  •  fearout   ( @fearout@kbin.social ) 
    5•1 year ago

    Here’s the abstract btw:

    Deep space observations of the James Webb Space Telescope (JWST) have revealed that the structure and masses of very early Universe galaxies at high redshifts (⁠z∼15⁠), existing at ∼0.3 Gyr after the BigBang, may be as evolved as the galaxies in existence for ∼10 Gyr. The JWST findings are thus in strong tension with the ΛCDM cosmological model. While tired light (TL) models have been shown to comply with the JWST angular galaxy size data, they cannot satisfactorily explain isotropy of the cosmic microwave background (CMB) observations or fit the supernovae distance modulus vs. redshift data well. We have developed hybrid models that include the tired light concept in the expanding universe. The hybrid ΛCDM model fits the supernovae type 1a data well but not the JWST observations. We present a model with covarying coupling constants (CCC), starting from the modified FLRW metric and resulting Einstein and Friedmann equations, and a CCC + TL hybrid model. They fit the Pantheon + data admirably, and the CCC + TL model is compliant with the JWST observations. It stretches the age of the universe to 26.7 Gyr with 5.8 Gyr at z=10 and 3.5 Gyr at z=20⁠, giving enough time to form massive galaxies. It thus resolves the ‘impossible early galaxy’ problem without requiring the existence of primordial black hole seeds or modified power spectrum, rapid formation of massive population III stars, and super Eddington accretion rates. One could infer the CCC model as an extension of the ΛCDM model with a dynamic cosmological constant.

    To clarify, tired light model proposes a hypothesis that the discrepancies in redshift are caused by light losing energy en route. Personally, I don’t really like this idea because it doesn’t really explain half the stuff, and introduces unnecessary unproven complexity. It’s not widely accepted as far as I know.

    Also, they’re calling the cosmological constants “covarying coupling constants”, which I think is kind of funny. Why not use “parameters” for your paper since your hypothesis implies they can change over time? Missed a chance to coin some cool new term :)

    •  bric   ( @bric@lemm.ee ) 
      1•1 year ago

      Can I ask what other factors tired light doesn’t explain? It sounds like an interesting idea, and at passing glance sounds a lot simpler than the universal expansion we’ve settled on, so I’m curious what makes that not the case

      •  fearout   ( @fearout@kbin.social ) 
        2•1 year ago

        Sure! I’m not too well-versed in this topic, but here’s a gist of it:

        First, it’s a very old idea, somewhere from 1920s I think. Proposed as a possible solution way before we found out about the expansion.

        One of the main issues is it violates conservation of energy, since in this hypothesis the photons lose energy en route, but there’s still no viable mechanism to absorb or account for that energy. It also doesn’t explain cosmic background radiation, while other theories explain it quite well.

        Then there’s blur. If the light loses energy on interactions and all that, the photons should scatter and blur the image. That doesn’t happen.

        And then there’s this time-dilation effect. When you look at supernovae at different distances, their explosions “run” at different paces, with further ones exploding slower. In LCDM model that’s easily explained by the light being stretched because of the expansion, and that’s what causes slower “runtime”. With TL’s predictions that shouldn’t happen at all, yet it’s an observable effect.

        And there are probably more discrepancies that I can’t remember off the top of my head.