Almost half of the matter of the universe is yet hidden from observation, literally unknown to us. Scientists have discovered the fast radio waves and faint X-rays, where all the unfathomable data is located. In a study published in Nature Astronomy on June 16, 2025, which used fast radio bursts (FRBs) in order to track the ordinary matter distribution across the universe within the nearby galaxies and in space. Another study used X-ray data to determine the long, hot gas filament that combines the four galaxy clusters. This study was published in Astronomy and Astrophysics.
A Cosmic Mystery: Where Is the Missing Matter?
As per NASA, ordinary matter includes everything which is visible and tangible, such as people, stars and planets. It is comprised of neutrons, protons or brayons. However, this accounts for around 15% of the total matter in the universe; the remaining is dark matter. Half of the baryonic matter is considered missing, and the reason for it is too diffuse to find it directly. This is scattered matter around the cosmos as a fine mist.
What Counts as Ordinary Matter
This hidden matter has been mapped using FRBs, intense millisecond-long pulses from galaxies located far away. With the help of 70 FRBs, which included one from 9 billion light years away, the scientists determined that around 76% of the ordinary matter lies within the galaxies, 15% around them in halos and other inside the galaxies.
A Unified Picture of the Universe’s Baryonic Matter
One more team examined the faint X-ray emissions to visualise matter from a 23 million light-year-long gas filament. Through noise filtering and analysing X-ray photons, the team found the gas to be over 10 million degrees Celsius with 10 protons per cubic meter, aligning with what models had suggested after predicting.
Implications for Galaxy Formation and Future Research
Altogether, these studies offer a clear picture of how and where ordinary matter exists in the universe. As scientists now combine methods like X-ray detection and FRB mapping, they are confident in the galaxy formation and other major cosmic secrets in depth.
