A groundbreaking study published on August 20, 2025, in *Physical Review D* proposes a startling new hypothesis: the accumulation of dark matter within exoplanets could lead to the formation of internal black holes.
Researchers from the University of California, Riverside, led by Mehrdad Phoroutan-Mehr, suggest that superheavy dark matter particles, if they exist and do not annihilate upon interaction, could be captured by exoplanets. These particles might then lose energy and drift towards the planet's core, accumulating over time. When this accumulated dark matter reaches a critical mass, it could collapse under its own gravity, birthing a black hole from within the planet.
The implications of this phenomenon are far-reaching, offering a novel avenue for understanding the enigmatic nature of dark matter, which constitutes a significant portion of the universe's mass but remains largely undetected. This research bridges the fields of exoplanet science and dark matter physics, suggesting that distant worlds could serve as cosmic laboratories for probing fundamental physics.
The study posits that the fate of such an internally formed black hole would depend on its mass. A more substantial black hole might begin to consume the planet's material, effectively turning the entire world into a black hole of planetary mass. Conversely, a less massive black hole could evaporate over time through Hawking radiation before significantly impacting the planet. This process could potentially occur within observable timescales, with the possibility of multiple black hole formations within a single exoplanet's existence.
Regions of the galaxy theorized to be dense with dark matter, such as the Milky Way's galactic center, are considered prime locations where this phenomenon might occur. The research highlights that exoplanet surveys could be instrumental in searching for superheavy dark matter particles by identifying potential signatures of these internal black holes.
While the concept of planets forming black holes is speculative, it is grounded in theoretical physics. The challenge for observational astronomy lies in detecting such events, as the gravitational signatures of planet-sized black holes might be difficult to distinguish from the planets themselves. However, future telescopes and missions are expected to provide the sensitivity needed to potentially observe indirect signs, such as anomalous heating or high-energy radiation emissions from exoplanets influenced by dark matter.
This research, published in *Physical Review D*, opens up new avenues for inquiry. It suggests that the absence of observed planet-sized black holes in known exoplanetary systems can also provide valuable constraints on dark matter models, helping to refine or rule out certain theoretical frameworks. The study's focus on superheavy, non-annihilating dark matter particles offers a distinct perspective from models involving weakly interacting massive particles (WIMPs), which are expected to annihilate upon interaction. The exploration of exoplanets as potential dark matter detectors represents a significant expansion of scientific inquiry, moving beyond traditional methods of studying stars and compact objects.