Hydrogen Gas Clouds Could Solve the Mystery of the Universe's Missing Matter, New Study Suggests

BERKELEY, CA — April 19, 2025: A new astronomical breakthrough may finally offer a solution to one of the universe’s most puzzling enigmas — the mystery of its missing non-dark matter. While scientists have long known that stars and galaxies account for only a portion of the universe’s matter, a vast amount of ordinary, or “baryonic,” matter has remained undetected — until now.

An international research team, led by astrophysicist Simone Ferraro from the University of California, Berkeley, has revealed that huge, faint hydrogen gas clouds extending far beyond galaxies may contain the elusive matter. The findings, published on the preprint server arXiv, suggest that these gas halos may bridge the gap in the universe’s missing matter budget.

Revealing the Hidden Cosmos: How the Research Unfolded

The team’s discovery relied on data from the Dark Energy Spectroscopic Instrument (DESI) — one of the most powerful cosmological survey tools available today. By stacking data from over 7 million galaxies, researchers were able to trace the barely-detectable halos of ionised hydrogen gas lurking at the outer boundaries of galaxies.

These halos, invisible through standard detection methods, subtly affect the cosmic microwave background (CMB) — the residual radiation from the Big Bang. This interference allowed scientists to indirectly detect the hydrogen clouds and theorize that they may form part of a larger cosmic web, possibly linking galaxies across immense distances.

Challenging Previous Assumptions About Black Holes

Interestingly, the study also revisits how supermassive black holes influence the intergalactic environment. Previously, astronomers assumed these black holes ejected gas early in their life cycle and then became dormant. But this new data suggests that black holes may remain intermittently active, continuing to expel gas over much longer periods.

Astronomer Boryana Hadzhiyska, part of the research team, noted:
“One of the most fascinating hypotheses we’re exploring is that black holes can switch on and off — they have a duty cycle. This continuous activity could be contributing to the dispersion of hydrogen across the universe.”

The Road Ahead: Incorporating the Findings into Cosmic Models

Now, cosmologists are looking to integrate these findings into existing theoretical models of the universe. Hadzhiyska emphasized the enthusiasm in the scientific community:
“Many researchers are eager to include these measurements in future simulations to more accurately depict the universe’s matter composition, especially the part that was previously missed.”

If confirmed by further observations, this study could profoundly alter our understanding of how ordinary matter is distributed in the universe — solving a cosmic puzzle that has baffled scientists for decades.