Astronomers have made a groundbreaking discovery that sheds new light on the universe’s composition and evolution. According to a study published recently, half of the universe’s hydrogen gas, which has long been unaccounted for, has been found. The missing matter, known as ionized hydrogen gas, forms a halo around galaxies and is more diffuse than previously thought.
The researchers used a novel technique called the kinematic Sunyaev-Zel’dovich effect to measure the distribution of this gas. By stacking images of approximately 7 million galaxies within 8 billion light-years of Earth, they were able to detect subtle changes in the cosmic microwave background radiation caused by the presence of electrons in the ionized gas.
The findings have significant implications for our understanding of galaxy formation and evolution. The discovery suggests that massive black holes at the centers of galaxies are more active than previously thought, fountaining gas much farther from the galactic center than expected. This has led to a new hypothesis about the duty cycle of active galactic nuclei (AGN) and the role of feedback in regulating star formation.
The study’s authors believe that this discovery will help resolve inconsistencies in cosmological models and provide insight into the large-scale structure of the universe. The technique used in the study could also be applied to probe the early universe and test gravity and general relativity.
This breakthrough has left the scientific community excited, with experts hailing it as a major advancement in our understanding of the universe. As one researcher noted, “Knowing where the gas is has become one of the most serious limiting factors in trying to get cosmology out of current and future surveys.”
Source: https://phys.org/news/2025-04-universe-hydrogen-gas-unaccounted.html