It’s a pictorial essay at less than 200 words but the gist is:
We’ve discovered many enormous galaxy “walls” in space.
Similarly, great cosmic voids exist between them.
A region of space devoid of matter in our galaxy reveals the Universe beyond.
These largest structures approach, but don’t significantly exceed, the expected cosmic limits.
But two classes of structures threaten this picture.
Three separate large quasar groupings are clustered across too-large cosmic scales.
Similarly galaxy groups from gamma-ray burst mapping surpass these limits.
If real, these structures defy our present cosmic understanding.
However, they may be purely phantasmal.
These signals may emerge from underlying random noise, with statistics incorrectly “discovering” non-existent patterns.Ethan Siegel, “The Largest Structures In The Universe May Not Actually Exist” at Forbes
It’ll be more fun at Forbes: with the pictures. But, essentially, if we don’t know whether the structures are real or not, why are we worrying about whether they “defy our present cosmic understanding”? First things first.
Meanwhile: Galaxy wall