James Webb Space Telescope complicates expanding universe paradox by checking Hubble's work

[Admin]

The JWST's findings further scientists' conundrum of having different measurements of the expansion of the universe, which may require new physics to resolve.

James Webb Space Telescope complicates expanding universe paradox by checking Hubble's work : Read more

 

[rod]

My note, using this cosmology calculator, https://lambda.gsfc.nasa.gov/toolbox/calculators.html, H0 = 73 km/s/Mpc and z = 0, age of the Universe 13.083 Gyr. Using 67.4 km/s/Mpc and z = 0, age of the Universe 14.169 Gyr. IMO, the Hubble tension indicates some globular clusters and stars dated can still be older than the age of the Universe in the BB model.

My note, from the 13-page PDF report, "1. Introduction In the past decade, an intriguing and persistent discrepancy referred to as the “Hubble tension”7 has been apparent at high significance (>5σ) between the Hubble constant (H0) directly measured from redshifts and distances, which are independent
of cosmological models, and the same parameter derived from the ΛCDM model calibrated in the early Universe (for a recent review, see Verde et al. 2023). The most significant disparity arises from the strongest constraints. These come from measurements of 42 local Type Ia supernovae (SNe Ia) calibrated by Cepheid variables, yielding H0=73.0 ± 1.0 kms^ −1 Mpc (SH0ES Collaboration; Riess et al. 2022, hereafter R22), compared to the analysis of Planck observations of the cosmic microwave background (Planck Collaboration et al. 2020), predicting H0=67.4 ± 0.5 kms^ −1 Mpc^ −1 in conjunction with ΛCDM." ref - https://iopscience.iop.org/article/10.3847/2041-8213/ad1ddd, 06-Feb-2024.

 

[Torbjorn Larsson]

This is progress as the Cepheid distances goes out to z ~.01! Earlier JWST Cepheid measurements did not cover the range up to z ~ 0.007 where the ladder methods that rely on Cepheid calibrations start to suggest new physics [~44:30 into the video "'Why I believe Planck', Prof. George Efstathiou, Kavli Institute for Cosmology, Cambridge, UK"

View: https://www.youtube.com/watch?v=QUKUT6JGuvw&ab_channel=IAA%CE%94%CE%95%CE%A4%2FIAASARS-%CE%95%CE%B8%CE%BD%CE%B9%CE%BA%CF%8C%CE%91%CF%83%CF%84%CE%B5%CF%81%CE%BF%CF%83%CE%BA%CE%BF%CF%80%CE%B5%CE%AF%CE%BF%CE%91%CE%B8%CE%B7%CE%BD%CF%8E%CE%BD
]. So now we have a stark disagreement between those near universe cosmology methods that use the tip of the read giant branch calibration and those that use the Cepheid calibration [see the video].

The tip of the read giant branch calibration gets values consistent with both most distant universe cosmology measurements and the Cepheid calibration methods. Another recent near universe method that agrees perfectly with LCDM of the distant universe cosmology is the X-ray eROSITA survey (but its weakness is that it is a sole data analysis so far, e.g. weak lensing agrees with the Cepheid calibration and those are repeated analyses).

Meanwhile it has become almost safe to say that the solution to the differing measurement values do not lie in new physics, as various surveys have excluded it from both the near and distant universe. This seems analogous to the early days of measuring light speed in vacuum, where measurements disagreed but the early average was 10 % from the modern figure - but no new physics appeared when the measurements improved.

IMO, the Hubble tension indicates some globular clusters and stars dated can still be older than the age of the Universe in the BB model.

That is one reason why the Cepheid calibration methods tend to suggest new physics, they are mildly inconsistent with LCDM. Mildly as in I think there is overlap between their age suggestion and its uncertainty range and the star and cluster ages and their uncertainty, there usually is. Their inconsistency lies within their own data [see the video reference above] and in respect to other metods or calibrations.