A massive structure hidden in deep space challenges our understanding of the universe

The presence of huge structures hidden in the immensity of the universe has always fascinated scientists. Astronomers recently discovered a massive ring of galaxies with a diameter of 1.3 billion light-years! This giant structure is called the Big Ring, and does not correspond to any structure or formation mechanism known so far. This discovery partly calls into question our understanding of the evolution of the universe, and thus could lead to a modification of the Standard Model of cosmology.

In June 2021, astronomers from the University of Central Lancashire, led by Alexia Lopez, discovered a giant arc of galaxies dubbed the Giant Sagittarius. The giant arch, located 9.2 billion light-years from Earth, is believed to be the first very large structure of its kind ever discovered.

Last January, during the 243rd Congress of the American Astronomical Society, held in New Orleans, Lopez announced the discovery of a second structure at a distance of 12 degrees from the giant arc. It is called the Great Ring, and its circumference is 4 billion light-years and its diameter is 1.3 billion light-years. His discovery was the subject of an article previously published on the platform
arXiv.

Cosmic puzzle

If the giant arc has left astronomers scratching their heads in 2021, the great ring only deepens the mystery. ” Neither of these supermassive structures is easy to explain within our current understanding of the universe Lopez said in a statement I reported. ” Their extremely large sizes, distinctive shapes, and cosmic proximity certainly tell us something important, but what exactly? “, she continued.

According to Lopez and colleagues, the earliest known structures result from baryonic acoustic oscillations (BAO). These are giant circular arrangements of galaxies in deep space. These oscillations come from fossils of sound waves arranged in a ring that propagated in the early universe, then appeared frozen in space.

However, an in-depth analysis of the “large ring” highlighted the fact that this structure is not consistent with this hypothesis. In fact, BAOs are about a billion light-years across, and the Great Ring is not circular either. It is very similar to the shape of a key, in that it is aligned so that it looks like a ring.

Therefore, the scientific community wonders about the impact of this discovery on the standard model of cosmology, especially on the principle of properties. In fact, according to the Standard Model, the universe appears identical, regardless of the direction in which it is observed (isotropy), and does not present significant differences from one point to another (homogeneity). Moreover, Lopez says, “We expect matter to be uniformly distributed everywhere in space when we observe the universe on a large scale, so there should be no obvious irregularities at all beyond a certain size.”

According to Lopez, astrophysicists have always estimated that the theoretical limit on the size of structures in deep space is about 1.2 billion light-years. However, both the Giant Arc and the Great Ring are much larger than that. In addition to their alarming size, studying the evolution of these structures is itself problematic. Some of its properties are difficult to explain within the current cosmological model.

However, alternative explanations have been proposed and may offer promising approaches. Among them is the conformal cyclic cosmology (CCC) model, proposed by Roger Penrose. It indicates that the universe is going through endless cycles of expansion, and that the current cycle will be neither the first nor the last. Therefore, the discovery of these two very large structures could constitute evidence to support this model.

Another hypothesis suggests that these two giant rings are some kind of topological flaw in the fabric of space-time. These “cosmic strings,” according to cosmologist Jim Peebles, appear as stringy defects in the early universe, where spacetime expanded and froze. Today, although there is no direct evidence yet for the existence of cosmic strings, the theoretical evidence is promising. They also suggest that these strings could be responsible for other properties in the distribution of galaxies.

” According to current cosmological theories, such structures on such scales are impossible “Says Lopez.” We can expect one very large structure in the entire observable universe. However, the Great Ring and the Giant Arc are enormous, and are even cosmically adjacent, which is pretty cool », concludes Lopez.

source : arXiv