The 'Huge-LQG' quasar 'structure' does not violate homogeneity

AI Thread Summary
The Huge-LQG quasar structure, initially thought to challenge the cosmological principle of homogeneity, has been shown not to violate this principle. A recent paper confirms that the quasars actually support the expected homogeneity of the Universe. Discussions highlight that previous claims of significant nonuniformity often dissipate over time, reinforcing the Cosmological Principle. Observations that once sparked doubt, such as "dark flow" and the "Sloan Great Wall," are typically understood as statistical fluctuations. Overall, the consensus remains that the Universe exhibits large-scale uniformity despite occasional challenges.
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There was some excitement a few months ago about the discovery of the Huge-LQG quasar structure, claimed to be the "largest structure in the Universe", which was said to violate the cosmological principle and the assumption of homogeneity of the Universe. Some previous threads on this topic on this forum are here and here.

Turns out this claim is wrong. A recently published paper (journal version here, free access version here) shows that the quasars actually support homogeneity as expected. A blog post explaining the issues at a less technical level is

Quasars, homogeneity and Einstein

A one-line summary would be "structures do not invalidate homogeneity; and the Huge-LQG is not really a structure anyway".
 
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Very interesting, thanks for the link
 
thats good news thanks for posting that, lol I will have to adjust my thinking on when Homogenous is considered. I used to use the value 100 Mpc. I'll have to adjust to 130 Mpc.
 
It seems that cosmologists like to challenge their own assumption of uniformity. From time to time some observations are found that seem to indicate significant nonuniformity and we hear doubts about homogeneity and isotropy (the roughly even distribution of matter at large scale).
Examples: "dark flow", Large Quasar Group (LQG), "Sloan Great Wall", "cold spot" or "great void".

After a while the excitement about a particular challenge quiets down and whatever it is seems to be accepted as understandable as a fluke or statistical fluctuation within the context of overall large-scale average uniformity. I don't know much about this at a detailed level, only a vague impression of general consensus that the Cosmological Principle still seems acceptable.

I wonder if there's a recent review article about this. Not just Large Quasar Group or anyone specific challenge, but giving an overview.
 
https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
The formal paper is here. The Rutgers University news has published a story about an image being closely examined at their New Brunswick campus. Here is an excerpt: Computer modeling of the gravitational lens by Keeton and Eid showed that the four visible foreground galaxies causing the gravitational bending couldn’t explain the details of the five-image pattern. Only with the addition of a large, invisible mass, in this case, a dark matter halo, could the model match the observations...
Hi, I’m pretty new to cosmology and I’m trying to get my head around the Big Bang and the potential infinite extent of the universe as a whole. There’s lots of misleading info out there but this forum and a few others have helped me and I just wanted to check I have the right idea. The Big Bang was the creation of space and time. At this instant t=0 space was infinite in size but the scale factor was zero. I’m picturing it (hopefully correctly) like an excel spreadsheet with infinite...
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