One of the the main pillars of modernity cosmology may begin to vibrate. A reading published in Nature has found evidence that the world it may not do the same in every direction on large visible scales.
“What we discovered is a network of massive filaments and galactic walls that have remained connected and interconnected across billions of light-years,” says Francesco Sylos Labini, director of physics research at the Enrico Fermi Research Center in Italy and lead author of the study.
What Should the World Be Like?
To explain the results, Sylos uses an analogy simpler than any mathematical equation. Imagine a world map in which each galaxy is represented by a single dot. If the world is to be equal on a larger scale, he explains, there should come a time when the map looks equal in every direction. Like a photograph viewed from a distance, its details would slowly fade together until only the scenery remained.
But that’s not what Sylos and his colleague Marco Galoppo discovered.
“The idea that the universe becomes statistically uniform on large enough scales is what allows us to describe it using simple mathematical models,” Sylos says. Their observations, however, suggest that the real world may remain more structured and ordered than this picture suggests.
In other words, the organization of these large global networks does not disappear as larger areas of the world are explored. Instead of gradually fading into a featureless background, the largest cosmic structures retain recognizable patterns even at scales where, according to the standard cosmic model, those patterns should no longer be detectable.
There is no Universal Arrow but an Ongoing Pattern
The researchers emphasize, however, that this search requires important qualifications. It does not mean that the world has one preferred axis or direction.
“We’re not claiming that the whole universe has one preferred direction, as if there was a celestial arrow going through the sky,” Sylos says. “What we found was more subtle.”
Instead, the team discovered consistent patterns in the distribution of galaxies that persist at incredibly large distances.
As the volume of the observed universe increases, the galaxies should eventually be distinguishable from a uniform background, such as the faint image in the previous analogy. “Instead, as we expand our field of view, new robust structures continue to emerge,” Sylos says. “Instead of turning to equality, the global network remains organized on a much larger scale.”
The conclusion is the culmination of more than two decades of research. Since the early 2000s, Sylos has tried to answer a question that is rarely tested directly: how do we know that the universe is uniform and isotropic on large enough scales? (An isotropic medium has the same physical properties in each direction.)
