Astrology

A study finds that a rapidly spinning black hole could theoretically split in two.

A black hole spinning extremely fast could split into two smaller black holes under particular conditions, according to a theoretical study reported by EarthSky. The researchers examined the physical laws that normally prevent such a split and found that it would be unlikely in most circumstances.

The study appeared in the peer-reviewed journal Physical Review D on October 22, 2026, EarthSky reports. Astronomers have not found evidence of a black hole splitting in nature, so the proposed process remains a theoretical possibility rather than an observed event.

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Spin could change the entropy calculation#

One obstacle is entropy, which BGNES describes as a measure of the microscopic arrangements that look identical from outside a system. EarthSky reports that splitting a non-rotating black hole would reduce the total entropy of the resulting system, conflicting with a law of thermodynamics.

Rapid rotation changes the relationship between a black hole's mass, spin and entropy, according to BGNES. ZME Science reports that the study considers whether spin could become orbital motion as two fragments move apart, leaving their combined entropy at least as high as the original black hole's.

The calculations were carried out by Francesco Sannino, Giacomo Cacciapaglia, Manuel Del Piano and Vania Vellucci, Universe Today reports. Sannino is affiliated with the University of Naples Federico II and the University of Southern Denmark, according to the outlet.

The fragments would need to separate#

The proposed split has another condition: the resulting black holes must move apart instead of falling back together, EarthSky reports. According to Universe Today, Sannino said the requirement leaves only a narrow possibility, perhaps confined to black holes spinning nearly as fast as they can.

The team calls the proposed shape a "pair-of-pants topology," Universe Today reports. In the scenario, the event horizon, the boundary beyond which nothing can escape, would branch into two parts resembling trouser legs as the black hole divided.

EarthSky reports that black holes can collide and merge into a more massive one. For the reverse process, the study's calculations leave open the possibility of two separate black holes only under the stated conditions, including sufficient separation after a split, according to Universe Today.

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