Hubble Tension in Perspective

In my office today for the first time in a couple of months I stumbled across a folder containing the notes from the summer school for new Astronomy PhD students I attended in Durham in 1985. Yes, that’s thirty five years ago..

Among the lectures was a set given by Richard Ellis on Observational Cosmology from which I’ve taken this little snippet about the Hubble Constant:

It’s not only a trip down memory lane but also up the cosmological distance ladder! You will see that there were two main estimates, one low and one high. Both turned out to be about three sigma away from the currently-favoured value of around 70.

Plus ça change, plus c’est la même chose…

Does this change your mind about today’s tension between another pair of “low” (67) and “high” (73) values?

5 Responses to “Hubble Tension in Perspective”

  1. Shantanu Desai Says:

    What is infall?

    • telescoper Says:

      The motion of the Local Group towards the Virgo cluster, the presence of which distorts the velocity field away from a pure Hubble flow.

  2. Phillip Helbig Says:

    I doubt that anyone will ever answer my question regarding the ultimate source of the discrepancy a few posts back.

    If I recall correctly, in addition to the infall correction, a major source of discrepancy was the distance to the Virgo cluster, on which Sandage and de Vaucouleurs disagreed.

    Sandage always got a low value, even with his HST project using Cepheids.

    I had the pleasure of hearing him lecture at a Saas-Fee course back in 1993. He was a good lecturer. (As far as I know, he never had a teaching position.) It was very clear, though, that he was completely convinced that Omega_matter is 1 and that the cosmological constant is zero. The first point was because that’s what inflation predicts; at least that’s how he saw it. Not sure about the second point. The cosmological constant is sort of like ABBA: most people either intensely dislike it or happy to have it around. (I’m in the second category on both fronts.) Of course, with the known age of the oldest objects and assuming (as he did) FRW models, this means that the Hubble constant must be low. I don’t know whether he was attracted to the idea of the inflation-inspired Einstein-de Sitter model because it implied the low value he had been getting for decades. (Sandage started working with Walter Baade when Alan Guth was just two years old. He really was of a different generation. He mentioned that when he started out, the computers in the cellar were about 20 years old and all female. Most of the audience didn’t even know what he was talking about.)

  3. aha…Durham..i was there 83-90…phd with Richard Ellis then postdoc….

  4. […] the talk, Colin Hill explains how even though early dark energy can alleviate the Hubble tension, it does so at the expense of increasing other tension. Early dark energy can raise the predicted […]

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