Trying to gain some insight on the Hubble Tension with Adam Riess at UCI special physics colloquium

 Greetings from Palmia Observatory,

Well, this week I finally made it back to the UCI physics colloquium to hear Nobel winner Adam Riess speak about the Hubble tension.

Riess spoke at a mostly full auditorium on how JWST measurements helped reduce the uncertainty of measurements of the Hubble constant by reducing some of the potential errors involved in distance measurements based on supernova distance correlations.

Inside the special physics colloquium at UCI, June 2, 2026 (Source: Palmia Observatory)

He went through a lot of the statistics showing how the increased number of measurements pretty much shows that the current estimate to be 73.04 +/- 1.04 km/s/Mpc, which differs by a statistically quite significance from the value of 67 km/s/Mpc as determined by measurement of the CMB.

This resulting tension has been around for almost 10 years now and Riess went on to describe a plan for potentially resolving the tension.  He laid out four approaches to do so as outlined in the screenshot below.

Four potential avenues for resolving the Hubble Tension (Source: Adam Riess)

Well, I was not that well acquainted of any of these four approaches, so after the colloquium, I elected to ask Grok, to explain it all for me.  So, I just uploaded the above screenshot to Grok, in this example, and asked it to review and provide some paper references for me to look at later.  So, Grok had to turn the photograph into text and then do the research to find descriptions and papers to match the ideas. So here is the prompt given to Grok and the first page of a multiple page response.

Grok generated analysis of Adam Riess's slide (Source: Palmia Observatory)

The rest of the Grok analysis looked more closely into the four ideas presented by Riess.  The following screenshot covers the first two ideas.

Grok generated analysis of Adam Riess's slide (Source: Palmia Observatory)

This next screenshot shows the last two ideas.

Grok generated analysis of Adam Riess's slide (Source: Palmia Observatory)

As a check on how accurate the Grok analysis was, I looked up the first of the referenced papers, and it was one where Riess discussed the idea of Early Dark Energy that could have impacted the CMB to make its measurement of the Hubble constant lower than the estimate based on Type 1a supernovae measurements today.

Proposed Early Dark Energy as possible resolution of Hubble Tension (Source: arXiV:2211.04492v1)

Ok, at least in this instance Grok did not imagine too far away from reality and actually looked up and found a valid reference paper applicable to the topic. If you want to look up any of the dozens of papers found in the Grok analysis, you can find the entire Grok conversation here: Grok analysis of Adam Riess Slide

Now for me, I still am just trying to remember the details of all these issues.  So there is still a lot of work and remembering the details for mel

Until next time,

Resident Astronomer George

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