There is a giant ring in the universe

A research team from the University of Central Lancashire (UK) announced that it had discovered a “large-scale structure of the universe”, estimated at 1.3 billion light-years in diameter. If confirmed, it would be one of the largest structures ever observed, and would likely cast some doubt on current theories trying to explain the way the universe is organized.

In general, stars are clustered into galaxies which in turn form: clusters of galaxies, clusters of galaxies and superclusters of galaxies, but also “walls” and “strings” (different ways in which multiple galaxies appear to us to be organized). These structures are separated from each other by large voids, to the point of giving the impression that the visible universe is a kind of visible universe. world Wide Web.

Representation of the cosmic web (“Cosmic Web”) with large-scale homogeneous distribution of galaxies (NASA)

Until the end of the twentieth century, it was assumed that some types of superclusters were the largest structures in existence, and that they were distributed homogeneously and uniformly in every direction. Things changed in the 1980s with the discovery of larger structures, and in 1989 it appeared Great Wall CfA2It is a large group of galaxies whose extension is estimated at about 500 million light-years. Their presence indicates a concentration of matter, which at least partly calls into question theories about the nearly uniform distribution of the universe on a large scale (which is also frequently discussed in terms of dark matter and dark energy, as we explain at length here).

In April 2003, the giant cluster of galaxies known as… Sloane's Great WallIt extends 1.37 billion light-years across, nearly three times larger than the Great Wall of China (CfA2). But in 2021, there was news of a discoveryGiant bowYou can imagine a large number of galaxies lining up to form an arc 3.3 billion light-years long.

The new structure announced by the British research group has been named Big ring Its diameter is 1.3 billion light-years: therefore it is among the first places in the ranking. It is located about 9 billion light-years from Earth and cannot be seen with the naked eye. This discovery was revealed during a conference of the American Astronomical Society in New Orleans, USA, and has generated debate because it adds new elements to the large-scale structures of the universe.

In red is the Giant Sagittarius and in blue is the Great Ring, visible in the visible night sky (University of Lancashire)

After the first discoveries of this type, theories were developed that assumed the extension limit to be about 1.2 billion light-years, but both the Great Ring and the Giant Arc appear to contradict those hypotheses and may not be a minor exception.

If so, it should be reconsidered Cosmic principle, that is, the assumption according to which the universe is both homogeneous and isotropic on a very large scale (i.e., it behaves the same way in every direction we consider). These properties appear on a large scale, while at a lower level – such as a cluster of galaxies or the organization of a solar system like our own – the universe appears heterogeneous and more disordered.

The cosmological principle greatly limits the amount of cosmological theories, i.e. explanations of how the universe works, that can be considered possible and plausible. For this reason, news about large-scale structures is carefully followed because it may lead to a revision of some assumptions of this principle, a highly debated topic for which there is still no scientific consensus.

In the case of the Great Ring, identification was possible thanks to… Sloan Digital Sky Survey (SDSS), an initiative to identify and catalog quasars (extremely luminous galactic cores) at great distances. By exploiting their brightness, it is possible to detect the presence of very distant galaxy clusters, which lie between the quasars and our observation point, and thus extract information about the properties of those clusters. The collected data was then analyzed using different algorithms to determine the likelihood of large-scale structures through statistics.

This observing technique is gradually becoming more reliable, thanks to some important advances in sky observing techniques and in models and algorithms for extracting information from the collected data. However, there is always a risk that observation will lead to descriptions of structures different from what they appear to us. There may be distortions related to distances (particularly at depth, compared to how objects on the same plane appear to us from our vantage point), the way light passing through clusters of galaxies is observed, and the way light passing through clusters of galaxies is observed. It is reflected from these.