A new study claims that the universe isn’t entirely the same no matter where you look—a radical proposal

One of the most basic and accepted truths about the universe is that it’s pretty much the same everywhere you look. In other words, there is no “up” or “down” in the cosmos. No direction has more structure, more galaxies—more stuff—than any other. Cosmologists take this sameness for granted; it’s one of their foremost maxims, called the “cosmological principle.” But what if this dogma isn’t true at all? ù

A new paper published Wednesday in Nature by two physicists calls the cosmological principle into question. They argue that the universe’s structures do look significantly different depending on the direction you look. “In this survey, we find there are large-scale structures which define special directions,” says Francesco Sylos Labini, a physicist at the Enrico Fermi Research Center in Rome, Italy and one of the study’s authors.

Using data from the Dark Energy Spectroscopic Instrument (DESI), Labini and his co-author claim that the universe’s structures are far more complicated than existing models suggest, violating one of cosmology’s most sacred ideas.

“I will be very interested to hear the reaction of the community,” says Katherine Freese, a cosmologist at the University of Texas at Austin who was not involved in the new paper. Freese says that the study could challenge “the basic scaffolding for the universe that we all assume in our work.”

continues here https://www.scientificamerican.com/article/fundamental-principles-of-the-universe-called-into-question-by-two-physicists/