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

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SUMMARY

The discussion centers on the Huge-LQG quasar structure, initially claimed to be the largest structure in the Universe and a potential violation of the cosmological principle. Recent research confirms that this claim is incorrect, demonstrating that the quasars actually support the expected homogeneity of the Universe. The consensus among cosmologists remains that structures like the Huge-LQG do not invalidate homogeneity, with the accepted scale for homogeneity adjusted to 130 Mpc. Observations that challenge uniformity are often regarded as statistical fluctuations rather than definitive evidence against the Cosmological Principle.

PREREQUISITES
  • Understanding of the Cosmological Principle
  • Familiarity with quasar structures and their significance
  • Knowledge of large-scale structure in cosmology
  • Basic grasp of statistical fluctuations in observational data
NEXT STEPS
  • Research the implications of the Cosmological Principle in modern cosmology
  • Explore the concept of homogeneity in the context of large-scale structures
  • Investigate the significance of the Large Quasar Group (LQG) in cosmological studies
  • Read recent review articles on challenges to homogeneity and isotropy in the Universe
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Astronomers, cosmologists, and astrophysics students interested in the implications of large-scale structures and the validity of the Cosmological Principle.

Sesh
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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.
 

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