Nobel laureate Adam Riess and his colleagues have obtained refined data on the structure of the universe, indicating that dark energy accounts for about 66.2% of the total mass of the Universe, while the remaining 33.8% is occupied by visible and dark matter. The work was published in The Astrophysical Journal. The press service of the Harvard-Smithsonian Astrophysical Center (CfA) reported on the results of the work of scientists.

“We have refined the main cosmological parameters by analyzing the outbursts of more than 1,500 type 1 supernovae. In many ways, our Pantheon+ project is the culmination of more than two decades of painstaking collaboration between theorists and experimenters to unravel the nature of the cosmos.“, – said Adam Riess, professor at Johns Hopkins University in Baltimore (USA).

At the end of the last century, while observing type 1 supernovae, Riess and his colleagues discovered that the universe is not just growing, but is doing it faster and faster. The reason for the accelerated expansion of its boundaries, as physicists today believe, is the so-called dark energy, a mysterious substance or property of space, whose nature remains one of the main mysteries of modern science.

According to scientists’ past estimates, dark energy accounts for approximately 68% of the total mass of the universe, while visible and dark matter account for approximately 5% and 26% of the total mass of the universe. These values, as noted by Riess, were very approximate due to the small number of observations. This fact, as well as the recently discovered anomalies in the expansion rate of the Universe at different epochs of its life, prompted leading cosmologists and observer astronomers to launch the Pantheon+ project in 2019.

As part of this initiative, scientists continued to observe Type 1 supernova explosions, and also used other approaches to study the three-dimensional structure of the Universe, including observations of Cepheid variable stars. This allowed scientists to determine the exact distances between the Milky Way and distant galaxies and estimate the speed at which they move away from each other under the influence of dark matter.

In total, astronomers and cosmologists have tracked the outbreaks of more than 1.5 thousand supernovae of the first type, and also studied in detail four dozen distant galaxies in which such explosions of stars occurred and where Cepheid variable stars are present. Their periodic fluctuations in brightness have allowed cosmologists to accurately calculate the distance of these galaxies from the Milky Way.

As a result, scientists have doubled the accuracy of measurements of cosmological parameters, including the rate of expansion of the universe, as well as the proportion of dark energy, dark and visible matter. The first indicator, as noted by Riess, remains anomalously high for nearby objects – 73.4 kilometers per second per megaparsec (3.2 million light years). This became another argument in favor of the existence of anomalies in the process of expansion of the universe, discovered by the Nobel laureate and his colleagues in 2016.

In turn, the new calculations by Riess and his colleagues showed that the share of dark energy was previously somewhat overestimated – in fact, it is 66.2%, and not 68%, as was thought in the past. Similarly, the total share of visible and dark matter is about 33.8%, not 31%. In the near future, scientists plan to calculate how the shifts in cosmological parameters obtained by them will affect the nature of the distribution of galaxies and affect the overall appearance of the Universe as a whole.