A new study suggests that decaying dark matter may have played a crucial role in the formation of the universe’s first supermassive black holes, much earlier than previously thought. This theory could help explain why these massive objects appear so soon after the Big Bang, challenging existing models of cosmic evolution. The early universe remains a mystery, particularly when it comes to how such enormous structures could form so quickly.
Recent data from the James Webb Space Telescope has revealed the presence of massive black holes in the early universe, which contradicts traditional growth models that suggest a slower formation process. Researchers from the University of California, Riverside, and their collaborators propose that dark matter might not be entirely stable, opening up new possibilities for understanding the origins of these cosmic giants.
A Tiny Burst Of Energy That Set Off A Chain Reaction
Yash Aggarwal explains that each decaying dark matter particle releases a very small amount of energy—about “a billion trillionth” of what you would get from a AA battery. While this might seem insignificant, in the context of the early universe, it was enough to have a profound impact.
“Our study suggests that decaying dark matter could profoundly reshape the evolution of the first stars and galaxies, with widespread effects across the Universe,” he stated.
At that time, galaxies were essentially clouds of pure hydrogen gas. These clouds were highly sensitive, meaning even a slight energy input could cause them to collapse faster under gravity. This sensitivity could have been key in the formation of the first supermassive black holes.
Early Galaxies Reacting to Dark Matter
For Dr. Flip Tanedo from the University of California, Riverside, these first galaxies acted like natural detectors. Their sensitivity made them react to even the smallest energy inputs, including those from dark matter decay.
“The first galaxies are essentially balls of pristine hydrogen gas whose chemistry is incredibly sensitive to atomic-scale energy injection,” he explained. “These are the properties that we want for a dark matter detector — the signature of these ‘detectors’ might be the supermassive black holes that we see today.”
In this sense, the supermassive black holes we observe today may carry traces of those early interactions. Scientists are not detecting dark matter directly, but rather its possible effects on how cosmic structures formed.
A Narrow Range That Makes It Work
The team modeled how gas behaves when exposed to decaying particles, including candidates like axions. Their results point to a specific mass range, between 24 and 27 electronvolts, where conditions favor rapid collapse.
“We showed that the right dark matter environment can help make the ‘coincidence’ of direct collapse black holes much more likely,” said Dr. Tanedo.
The study indicates that this range makes it easier to form direct collapse black holes, which skip slower growth stages. Published on April 14, 2026, in the Journal of Cosmology and Astroparticle Physics, the work reflects collaboration between astrophysics, cosmology, and particle physics.
“The work stemmed from a series of coincidences that brought the right people together at the right time, including a series of workshops that connected particle physicists, cosmologists, and astrophysicists to discuss the big questions in their field,” he added. “In the same way, the support for interdisciplinary work helped make the ‘coincidence’ leading to this work possible.”
