Has JWST solved the crisis in cosmology?

[MrRobotoToo]

Dr. Becky Smethurst provides a summary of the latest analysis of JWST data by Freedman et al., indicating that there's no statistically significant discrepancy between the value of the Hubble constant thus obtained and the value obtained from Lambda-CDM using Planck data.

 

[pines-demon]

Dr. Becky Smethurst provides a summary of the latest analysis of JWST data by Freedman et al., indicating that there's no statistically significant discrepancy between the value of the Hubble constant thus obtained and the value obtained from Lambda-CDM using Planck data.

More specifically Dr. Becky said:

Last weekend a conference of the American Physical Society in Sacramento California, a giant in this field, Wendy L. Freedman presented her research group's latest work using data from JWST and now they're claiming a value of the Hubble constant that within error agrees with our best model of the universe. They're claiming now that there is no Hubble tension that the crisis in cosmology has been solved. Of course I had to make a video on this but everything I'm about to say comes with a very big disclaimer: no research papers have been released yet. This work is not peer reviewed. All we have to got on is the 35 minute talk that Wendy Freedman gave at this conference and the slides that go with it.

Emphasis mine.

 

[ohwilleke]

Color me skeptical.

The evidence of the Hubble tension comes from all sorts of independent sources using different methods (half a dozen maybe), generally indicating a larger Hubble constant in recent times, relative to the CMB estimate of the Hubble constant. And, the CMB estimate has a very low uncertainty.

The latest pre-prints to this effect rely on the observational data from DESI in just the last week (there is more discussion of the DESI result in another thread). See also, e.g., dam G. Riess, et al., "A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team" arXiv:2112.04510 (December 8, 2021). Another independent approach is found in James Schombert, Stacy McGaugh, Federico Lelli, "Using The Baryonic Tully-Fisher Relation to Measure H0" arXiv: 2006.08615 (June 15, 2020) and "The KBC void and Hubble tension contradict ΛCDM on a Gpc scale - Milgromian dynamics as a possible solution" Haslbauer, M. et al., 2020MNRAS.499.2845H.

Indeed, the tension may prove particularly hard to resolve as the most obvious simple tweak (early dark energy) may be insufficient to resolve it. See Sunny Vagnozzi, "Seven hints that early-time new physics alone is not sufficient to solve the Hubble tension" arXiv:2308.16628 (August 31, 2023) (accepted for publication in Universe). One proposal to explain the complexity with some data to back it up is that the Hubble tension is a reflection of an ansiotropic observable universe (i.e. a universe which isn't basically similar in all directions). Orlando Luongo, et al., "On Larger H0 Values in the CMB Dipole Direction" arXiv:2108.13228 (August 30, 2021).

At first, when the Hubble tension was attributed to a single recent time data set with significant systemic errors that could have been understated, this kind of resolution seemed more plausible. Indeed, a couple of papers that previous made this claim are Edvard Mortsell, et al., "The Hubble Tension Bites the Dust: Sensitivity of the Hubble Constant Determination to Cepheid Color Calibration" arXiv (May 24, 2021) and S.L.Parnovsky "Bias of the Hubble constant value caused by errors in galactic distance indicators" arXiv:2109.09645 (September 20, 2021) (Accepted for publication at Ukr. J. Phys).

But as more and more independent measurements of the late time Hubble constant tend to confirm each other, I don't see how one set of confirming data from the JWST could definitively disprove all of them. Really, the only way I could see it happening is if the JWST established that the Planck estimate of the Hubble constant from the CMB was too low due to some sort of overlooked systemic or theory error, because Planck is the dominant datapoint from which the Hubble constant is determined at high-z.

Stacy McGaugh suggests in a blog post that the Hubble tension is probably due to the estimate of Hubble's constant from the cosmic microwave background (CMB) which has gotten lower as greater precision measurements of it have been made, rather than from errors in recent time Hubble constant measurements as it is more common to suppose. He argues that observed early galaxy formation, which is contrary to the LambdaCDM model and thus not accounted for by it when calculating the early time Hubble constant from the CMB, is likely to be a big part of the discrepancy. So, he's basically arguing for a theory error rather than a measurement error (which seems inplausible) in deriving the Hubble constant from the Planck CMB measuements.

This might be the only plausible way that the JWST, which is unique in its ability to do conventional astronomy observations at very high-z, could reconcile the tension. In support of this hypothesis, McGaugh cogently notes that the Hubble tension is largely a result of falling CMB values as that measurement has been refined over time, rather than changing late time Hubble constant measurements, as illustrated in the following diagram:

I have only the slightest hint at what the analysis behind the JWST estimate might be from the screen shot (I'm in an environment where podcasts aren't really a viable medium for me):

But I'd need to know more about how the JWST estimate arises and what time frame is is measuring the Hubble constant at.