A groundbreaking study, published in March 2025 on the preprint server arXiv, reveals that ultralight dark matter might have played a pivotal role in the formation of supermassive black holes in the early universe.
The Mystery of Early Supermassive Black Holes
In the early universe, scientists have discovered black holes that are billions of times more massive than our Sun, appearing just a few hundred million years after the Big Bang.
This is a perplexing mystery because the conventional method of black hole formation, through the death of massive stars, wouldn’t work on such short timescales.
The process of a star collapsing into a black hole takes time—something that didn’t align with the rapid emergence of these enormous objects.
Ultralight Dark Matter: A New Solution?
A new hypothesis, proposed by Hao Jiao and colleagues at McGill University, suggests that ultralight dark matter could have helped facilitate the formation of these supermassive black holes.
According to the study, ultralight dark matter isn’t just a faint, invisible substance, but it might behave like a quantum ocean on galactic scales. This unusual characteristic allows dark matter to support waves, which, in turn, can lead to regions of higher dark matter density, known as resonances.
How Does Ultralight Dark Matter Work?
In the proposed model, the early universe, filled with gas clouds of hydrogen and helium, also contained these dark matter waves. As these waves amplified, regions of high dark matter density began to form. These pockets of energy could then convert into photons, creating light in a universe that had not yet seen the first stars.
However, this low-energy radiation alone wasn’t enough to prevent gas clouds from fragmenting into smaller stars. To overcome this limitation, the researchers suggest that these photons might have been thermalized, heating up the surrounding gas to high temperatures and thus producing the ultraviolet (UV) radiation necessary to prevent star formation and allow direct black hole collapse.
The Role of Gas Cloud Turbulence
Another key aspect of the model is the turbulence within gas clouds. Turbulence is known to amplify small-scale disturbances into larger ones, which could have provided a mechanism for low-energy radiation to transform into the high-energy radiation required to break apart molecular hydrogen.
This process may have helped prevent the gas clouds from fragmenting into stars, enabling them to collapse directly into black holes.
What Does This Mean for Our Understanding of the Early Universe?
If this theory is correct, it would rewrite our understanding of how supermassive black holes could form so early in the universe’s history. Rather than relying on the death of massive stars, the interaction of ultralight dark matter with gas clouds might have jump-started the creation of these cosmic giants. This could also open up new avenues for detecting ultralight dark matter itself, a task that has eluded scientists for years.
Exploring the Future of Dark Matter and Black Hole Research
While this model is promising, it’s still in the early stages. The results have not yet been peer-reviewed, and further research is necessary to validate the hypothesis.
One of the next steps will be to run more realistic simulations of the early universe to see if the proposed interactions hold up under different conditions.
Also, the search for ultralight dark matter itself is ongoing, and detecting this elusive substance could prove to be one of the most significant breakthroughs in modern astrophysics.
