Structures on Gigaparsec Scales

The latest in a sequence of claims of very large scale structures in the distribution that violate the cosmological principle emerged a week or so ago with a paper in Nature. The paper is behind a paywall but here is the abstract: I’ve been nudged a few times by various people to comment on that but I’ve been busy recently and didn’t have time to look at the paper in detail. I had a quick look today and the thing that immediately struck me was that I didn’t understand the mock catalogues they used to compare the ΛCDM model with the observations. I still don’t understand that but I’ve stopped worrying about it because today I received a preprint (not behind a paywall, but on arXiv) from Till Sawala with the title The local galaxy distribution does not violate the cosmological principle and the (rather devastating) abstract: The cosmological principle, which states that the Universe is statistically homogeneous and isotropic on sufficiently large scales, is a foundational assumption of…