In high resolution: a 3D map of the universe has been revealed

An international team of more than 900 scientists, from 70 research centers, has released the results of the most complex 3D mapping of the universe ever. The project's main goal is to understand dark energy, the force that drives the expansion of the universe. In the study, the researchers used a specially developed telescope called the Dark Energy Spectroscopy Instrument (Desi), located in the United States. Thanks to its cutting-edge technology, Desi has been able to map the locations of galaxies and quasars, the extremely bright cores of galaxies that can be seen at enormous distances, with up to 99% accuracy.

“So far we see that the data match our best model of the universe, but we also see some potentially interesting differences, which could indicate that this dark energy evolved over time,” said Michael Levy, director of the DICEY International Project. In other words, “the Dicey data seem to show that the cosmological lambda constant will not actually be a constant,” Arno Di Mattia said.

This may indicate that after accelerating 6 billion years after the Big Bang, this speed may have “slowed down more recently,” according to Christophe Yeshe, a physicist at the French Atomic Energy Authority (CEA).

Galaxies and quasars are essential for mapping the universe in 3D, as the light they emit is absorbed by intergalactic gas clouds throughout its journey. The pattern of light captured by the telescope reveals the distribution of matter throughout space. Some of the 450,000 sources Deci mapped are so far away that the light from them took about 11 billion years to reach Earth.

Time is crucial, because it allows scientists to reconstruct a relevant part of the universe's history, since the Big Bang, which occurred 13.8 billion years ago. The results of the mapping were detailed in a series of articles on the Arxiv portal. However, the work has not yet been subject to independent review, and the idea is to submit the results for evaluation by the specialized scientific community.

What was found in the map cooperates with the currently prevailing theory to explain the expansion of the universe, known as Lambda CDM. This line of research addresses two major forces affecting the evolution of the universe. One is gravity, which works in an attractive way. In addition to this force exerted by visible stars and galaxies, a large amount of cold dark matter, which accounts for more than 95% of the matter in the universe, also contributes.

The other essential element is dark energy. Unlike gravity, it is a repulsive force that accelerates the expansion of the universe. One relevant issue of this work is that it helps understand the early stages of the universe, even before the last 11 billion years. This contributes to the understanding of how baryonic oscillations – differences in the distribution of matter in the primordial universe – in the universe created the structures we observe today, such as stars, galaxies and galaxy clusters.

Nailton Araujo, an astronomer at Fundação Planetário do Rio de Janeiro, explains that the instrument created for the research does not “see” dark energy. “This energy was created theoretically to explain the behavior of a universe that has been expanding for a long time. As galaxies expand, they are moving away from each other. This can be measured by the red shift that light from these objects undergoes as they expand. They are moving away, and the device that started producing The results now measure a large number of moving galaxies.

According to the expert, the data obtained from the various objects analyzed indicate that the expansion of the universe may be slowing down. “But this is a relatively new field, let's wait for more experimental data.”

Salvador Nogueira, a science advocate and author of a series of books on astronomy, asserts that by combining data from the first year of Dicey's observations with other studies, scientists have found new features, and some subtle differences with respect to the Standard Model.

“This may indicate that dark energy is not constant over time, but rather varies. It is as if it could have more or less influence over time.” For him, it remains to be seen whether this is just a slight lapse in accuracy or if it is real. “It will only be possible to determine this with more data, but scientists are excited. After all, the DICEY mission will last for five years, which should improve the amount of data and the accuracy of the conclusions.”

Although the results obtained by Dicey are quite accurate, the project is ongoing, as more data is needed to fully understand dark energy and its evolution over time.

The older, the faster

“Edwin Hubble discovered that distant galaxies were moving away from us at progressively greater speeds. This is what we call Hubble's law. In plain terms: the farther away a galaxy is, the faster it is moving away. The explanation for this phenomenon leads to 'We believe that in the distant past, galaxies were together' In a small volume of space, from which it expanded. This is the big bang model. The relationship between the speed of galaxies and their age arises from the fact that the speed of light is limited. “Since the faster galaxies are the farthest, according to Hubble's law, their light also takes longer to reach us. That is why what we observe at very large distances are older galaxies.”

Verify information on Correo Brazilianense.