Astronomers have long been puzzled by the discovery of extremely large black holes in the early universe.
Some of these black holes, found less than a billion years after the Big Bang, are as massive as a billion suns.
According to current theories, there simply was not enough time for them to grow so big through normal processes. Now, a new study suggests that dark matter may hold the answer.
The research, led by scientists at University of California, Riverside, proposes that a slow “decay” of dark matter could have helped create the right conditions for these giant black holes to form quickly.
The study was published in the Journal of Cosmology and Astroparticle Physics.
Dark matter is a mysterious substance that makes up about 85 percent of all matter in the universe.
It does not emit light, so scientists cannot see it directly, but its gravity helps shape galaxies and the large-scale structure of the cosmos. In this new work, researchers explored what might happen if dark matter particles slowly release tiny amounts of energy as they decay over time.
Although each particle would release an extremely small amount of energy—far less than what is needed to power everyday devices—this energy could still have a big impact in the early universe.
At that time, galaxies were made mostly of simple hydrogen gas, which is very sensitive to even small changes in energy.
Normally, this gas cools down and forms stars. But the researchers found that if dark matter decay adds just enough energy, it can change the gas chemistry in a way that prevents star formation. Instead, large clouds of gas could collapse directly into black holes. This process, known as “direct collapse,” allows black holes to form much more quickly than usual.
Recent observations from the James Webb Space Telescope have found many surprisingly large black holes in the early universe. These discoveries have been difficult to explain using traditional models. The new study suggests that dark matter decay could make direct collapse events more common, helping to explain these observations.
The team used detailed computer models to study how gas behaves under the influence of decaying dark matter. They found that a specific range of dark matter particle masses could create the right conditions for this process to happen. This adds a new piece to the puzzle of how the first galaxies and black holes formed.
Researchers say this idea could help connect different areas of physics, including cosmology and particle physics. It also highlights how small effects at the atomic level can influence the evolution of the entire universe.
While more work is needed to confirm this theory, the study offers a promising new explanation for one of astronomy’s biggest mysteries. If correct, it means that dark matter not only shaped galaxies through gravity but also played a direct role in creating some of the universe’s earliest and most powerful objects.
Source: UC Riverside.
