The movement of satellite galaxies suggests that the universe is younger

According to an analysis of the motion of pairs of satellite galaxies around massive galaxy clusters, the universe may be younger than the standard model of big bang cosmology predicts. In standard cosmological models, the formation of cosmological structures begins with the formation of small structures, which subsequently undergo hierarchical fusion, leading to the formation of larger systems. As the universe ages, the massive groups and clusters of galaxies that are the largest systems tend to increase in mass and reach a more dynamically relaxed state. The motions of satellite galaxies around these groups and clusters provide valuable information about the state of their assembly. Observing such motion offers crucial clues about the age of the universe. Using public data from the Sloan Digital Sky Survey (SDSS), a research team led by Professor Guo Qi of the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) analyzed the kinematics of pairs of satellites around clusters of massive galaxies. The team’s findings, published in Nature Astronomy, suggest that the universe may be younger than the standard cosmological model predicted. Scientists studied the motion of pairs of satellites located on opposite sides of massive galaxy groups using their velocity deviations from the central galaxy along the line of sight. They found a significant excess of pairs showing correlated speed deviations compared to pairs showing anticorrelated speed deviations. “The excess of correlated satellite pairs suggests the presence of recently accreted or infalling satellite galaxies,” Professor Guo Qi, corresponding author of the paper, said in a statement. This excess was also found in the updated cosmological simulations, but the magnitude of the effect was considerably smaller than observed. The significant difference between observations and simulations suggests that massive groups of galaxies are younger in the real universe. “Since the age of massive groups of galaxies could be closely related to the age of the universe, these findings consequently suggest a younger universe compared to the universe inferred from the Planck Collaboration’s Cosmic Microwave Background (CMB),” said Dr. Gu Qing, first author of the article. These findings challenge the current cosmological model and, according to the authors, may provide valuable insights into the Hubble strain problem.