The universe is unexpectedly stringy, which could unravel the theory of the cosmos

Controversial claim challenges principle of cosmological sameness on which prevailing theory rests

By Adrian Cho for Science

Like a vast bowl of spaghetti, the universe may be stringy on length scales far larger than cosmologists have long assumed. In a study published today in Nature, two researchers argue galaxies align in enormous filaments even on scales where the cosmos should appear smooth and uniform. If correct, the bold claim would upend the cosmological principle, the conceptual cornerstone of the standard cosmological model.

“This is serious,” says Subir Sarkar, a cosmologist at the University of Oxford who was not involved in the work. “If there is a real contradiction between what you expect and what you find, that would be progress, right?” Abandoning the cosmological principle could even eliminate the need for dark energy, the mysterious space-stretching stuff thought to be accelerating the expansion of the universe, some cosmologists say. But others are skeptical of the new claim.

The cosmological principle holds that the universe is homogeneous (the same everywhere) and isotropic (the same in all directions). A quick glance at the night sky shows this cannot be true at all levels, because the void of space is dotted with dense clumps of stars. Nevertheless, cosmologists assume the universe is essentially uniform and featureless when averaged over sufficiently long length scales, much as a pixelated photo looks smooth when viewed from a distance.

Continue here: https://www.science.org/content/article/universe-unexpectedly-stringy-which-could-unravel-theory-cosmos