Can Black Holes Split? Theoretical Study Explores Rare Cosmic Event

A new theoretical study from the University of Southern Denmark suggests that under extreme conditions—particularly rapid rotation—a black hole could potentially split into smaller ones. This would contradict the common view that black holes only merge, not divide. Such a process remains highly speculative and would require very specific physical parameters.

A theoretical study led by researchers at the University of Southern Denmark, published in Physical Review D on October 22, 2026, explores the possibility that black holes could split under extreme conditions—specifically, when rotating near their maximum possible rate. The work, co-authored by Francesco Sannino from the University of Naples Federico II and the Quantum Field Theory Center at SDU, challenges the long-held assumption that black holes only merge, never divide. The study uses the concept of “pair-of-pants topology” to model how a single black hole might branch into two or more smaller ones, but only if rotational energy overcomes thermodynamic barriers. Crucially, such a split would require the resulting black holes to move apart rather than recombine, which limits the scenario to only the most rapidly spinning objects. The research builds on prior understanding of entropy and the second law of thermodynamics, which generally prohibit a system from decreasing total entropy in a spontaneous process—making splitting unlikely for non-rotating or slowly rotating black holes.

The background stems from decades of observational evidence showing black hole mergers via gravitational wave detections (e.g., LIGO/Virgo), reinforcing the idea that black holes grow through collisions. However, this study opens a speculative path toward reversal mechanisms under exotic conditions. While no empirical evidence supports splitting yet, the work invites reconsideration of black hol