A groundbreaking study led by the Center for Astrophysics | Harvard & Smithsonian (CfA) has uncovered the Universe's 'missing' matter using Fast Radio Bursts (FRBs) as a guide. These FRBs, brief and bright radio signals from distant galaxies, have helped astronomers detect where more than three-quarters of the Universe's ordinary matter is hidden - in the thin gas between galaxies. This discovery represents a significant leap in understanding the interactions of matter in the Universe.

Previously, scientists struggled to locate at least half of the Universe's ordinary matter, mostly composed of protons. Techniques like X-ray emission and ultraviolet scans of distant quasars were used to search for this missing matter, believed to exist as a thin, heated gas between galaxies. However, the gas's high temperature and low density made it challenging to observe directly, leaving its quantity and exact location uncertain.

Fast Radio Bursts (FRBs) have changed the game. These short, bright radio signals from faraway galaxies have allowed researchers to identify the missing matter as the intergalactic medium (IGM), the space between galaxies. By analyzing 60 FRBs, astronomers determined that about 76% of the Universe's baryonic matter resides in the IGM, with a small percentage found in stars, cold galactic gas, and galaxy halos.

Lead author of the study, Liam Connor, described FRBs as 'cosmic flashlights' that illuminate the intergalactic medium. By measuring how much each FRB signal was slowed down, researchers were able to 'weigh' this invisible matter. The results confirmed that the majority of baryonic matter is distributed in the IGM, aligning with predictions from cosmological models.

This breakthrough sheds new light on the Universe's structure and composition, offering insights into the formation of galaxies and the movement of matter across vast distances. As Connor explained, feedback mechanisms like supermassive black holes and exploding stars play a crucial role in redistributing baryons, influencing the cosmic thermostat.

Looking ahead, the future of FRB cosmology appears promising. With advanced radio telescopes on the horizon, such as the DSA-2000 and the Canadian Hydrogen Observatory and Radio-transient Detector, thousands of FRBs are expected to be detected, enabling a detailed mapping of the cosmic web.

Source: AZoQuantum