2023-09-05 17:15:47
After a complex statistical analysis with around a million galaxies, some scientists have culminated their study with the elaboration of a method that will from now on make it possible to establish cosmological distances with greater precision.
The work is the work of researchers from various Chinese universities and the University of Cordoba in Spain.
The new method is specifically used to detect the so-called Baryon Acoustic Oscillations (BAO). These waves, first demonstrated to exist in 2005, are one of the few traces of the Big Bang (the colossal “explosion” with which the universe was born) that can still be glimpsed in the cosmos. They propagated during the first 380,000 years of the universe’s life, expanding through matter so hot that it acted like a fluid, much like dropping a stone into a pool of water. Subsequently, the universe expanded and cooled to the point that these waves were frozen in time until the present.
The interesting thing about these oscillations, witnesses of almost the entire history of the cosmos, is that they have a perfectly known length (500 million light-years), which is why they are currently very useful for measuring cosmological distances from the separation between galaxies. Being able to detect them and know their size is therefore of the utmost importance to correctly map the universe to very distant points.
Artistic recreation of baryon acoustic oscillations (Image: Zosia Rostomian / Lawrence Berkeley National Laboratory)
“The results of this study now allow us to detect these waves through a new and independent method from the traditional one. By combining both, we can establish cosmic distances with greater precision”, explains Antonio J. Cuesta, a researcher at the Department of Physics at the University from Córdoba and the only Spanish member of the team, headed by Kun Xu, from Shanghai Jiao Tong University in China.
The authors of the study have crossed, through statistical methods, a database with close to a million galaxies, paying special attention to two very different magnitudes: the ellipticity of the galaxies and the density around them.
Normally, galaxies orient themselves by stretching towards where there are a greater number of other galaxies due to the pull of gravity, but there are certain places in the universe where this rule is not followed as strongly. “It is at those points, where the galaxies do not point where they should, where statistics tell us that the so-called Baryon Acoustic Oscillations are located, since these waves also act as a point of attraction for gravity”, emphasizes Antonio J . Costs.
“The first practical application that this work could have is to establish more precisely where the galaxies are located and the separation between them and the Earth, but in some way we are also peering into the past”, explains the researcher.
This new approach to Baryon Acoustic Oscillations, vital to answer some of the big questions about the universe, opens new doors to the world of astronomy. Establishing cosmological distances offers, in turn, new clues about the history of the expansion of the universe and helps to better understand its composition in terms of matter and dark energy, two of the most elusive and enigmatic components of the cosmos.
The study is titled “Evidence for baryon acoustic oscillations from galaxy–ellipticity correlations”. And it has been published in the academic journal Nature Astronomy. (Source: UCO)
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