Scientists Find Evidence for the Origin of Mysterious 'Impossible' Black Holes
The Puzzle of Intermediate-Mass Black Holes
For years, astronomers have known that the universe contains black holes that don't neatly fit into existing categories. Stellar-mass black holes form when massive stars collapse, while supermassive black holes lurk at the centers of galaxies and grow to enormous sizes. But in between these two classes lies a mysterious gap: intermediate-mass black holes (IMBHs) ranging from about 100 to 100,000 solar masses.
These IMBHs have been detected but their formation mechanism remained unclear—standard stellar evolution can't account for their masses, yet they seem too small to be "baby" supermassive black holes.
New Evidence Points to an Origin
Recent observations and theoretical work have begun to shed light on where these middle-weight black holes come from. Rather than forming through a single mechanism, evidence suggests they likely arise from the direct collapse of massive gas clouds or through runaway collisions in dense stellar clusters, bypassing the typical stellar death pathway.
This research represents a significant step in understanding black hole formation across the full cosmic mass spectrum and may help explain how supermassive black holes themselves get their start.