Talk:Georges Lemaître

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From the article: "This 1927 paper had little impact because the Annales de la Société Scientifique de Bruxelles were not widely read by astronomers or physicists outside of Belgium. Moreover, the initial state that Lemaître proposed for the Universe in this 1927 paper was Einstein's model of a static universe with a cosmological constant, but at this time, Einstein insisted that only a static picture of the universe was physically acceptable."

This reads like: The paper had little impact because it proposed a static universe, however, Einstein insisted on a static universe.

I'm not entirely fluent on astrophysics but this is surely not what the sentence is supposed to be. WittgensteinsKey (talk) 18:17, 17 January 2026 (UTC)

That sentence was indeed somewhat garbled. What Lemaître assumed in 1927 was the Universe started in almost, but not exactly, Einstein's static regime, because any deviation from the exact value of the cosmological constant that gives a static universe, no matter how small, will lead to an expanding or contracting universe. I've rewritten this passage to at least avoid the appearance of a contradiction. - Eb.hoop2 (talk) 00:54, 18 January 2026 (UTC)

Summarize Timeline Fact Check

As the article reads at present, one could readily get the impression that Lemaître had at his disposal observational evidence for the Hubble-Lemaître law, which states that the velocity at which galaxies appear to recede from the observer increases proportionally to distance.

This is definitely not the case. Lemaître provided a cosmological solution of the Einstein field equations, which predicted the Hubble-Lemaître law. He then looked for data and quoted those published by Strömberg, the observations being attributed by Strömberg to Slipher. Strömberg in the conclusion of the paper states that: "In conclusion we may say that we have found no sufficient reason to believe that there exists any dependence of radial motion upon distance from the sun." Since this is the paper quoted by Lemaître, it is clear that Lemaître also does not claim to have observed a proportionality between distance and outward velocity. What was the case, however, was that most galaxies showed velocities receding from the Sun.

What Lemaître then did, to devise an observational estimate for the expansion rate of his model, was to divide the average velocity of all galactic velocities measured by Strömberg by their average distance. On the other hand, Hubble in 1929 actually found observationally a correlation between velocity and distance.

I suggest replacing: "Lemaître connected this prediction to what he argued was a simple relation of proportionality between the average recessional velocity of galaxies and their distance to the Earth." in Work on Cosmology by the following

"Lemaître's model predicted a linear relationship between the recessional velocity of galaxies and their distance to the Sun. The then available data used by Lemaître (G. Strömberg, "Analysis of Radial Velocities of Globular Clusters and Non-Galactic Nebulae". Astrophysical Journal. 61: 353–362. 1925. ) showed no such correlation, but did show that the great majority of the galaxies observed had a velocity pointing away from the Sun. To provide an observational estimate for the expansion rate of his model, Lemaître divided the average velocity of all of Strömberg's gaxies by their average distance, obtaining an estimate of 625 km/s per megaparsec." Falw (talk) 22:15, 3 April 2026 (UTC)