Spinning Black Holes Could Split in Two, Theoretical Study Finds

How could rapid rotation change the answer?

Rotation could reopen the door. A rapidly spinning black hole carries rotational energy, and that energy changes the conditions under which a split might occur. Under the right theoretical setup, one hole could branch into two or more smaller ones.

Physicists describe this shape-shifting with a memorable name: pair-of-pants topology. Picture a pair of pants, with one opening at the top branching into two legs below. The original black hole is the waist; the two daughter holes are the legs.

But there's a second requirement. The two newborn black holes must be able to move apart rather than fall back together. And when the researchers built that into their calculations, the possibilities narrowed sharply.

"When we include this requirement, the window largely closes again, except possibly for black holes rotating close to their maximum possible rate," Sannino said.

What about extra dimensions?

The study also explores more exotic scenarios, at least for now purely theoretical ones. Some theories propose that our universe has extra spatial dimensions beyond the three we experience — up and down, back and front, side to side.

In higher-dimensional models, certain black holes can become unstable and start breaking apart. There, the researchers found, splitting could become much more likely, because the total entropy could increase rather than decrease, making the split thermodynamically favorable.

Plenty of unknowns remain, though. Sannino said: "We cannot yet give a single probability for a black hole to split. It depends on how gravity behaves beyond Einstein's theory, and we are working to quantify this."

The team expects that small primordial black holes — hypothetical miniature black holes theorized to have formed in the first fraction of a second after the Big Bang — would be more prone to splitting than much larger astrophysical black holes.

How could we ever detect a split?

Direct observation is off the table for now. But an indirect signal might be within reach. Gamma-ray telescopes such as Fermi-LAT, Sannino noted, can search for signals from tiny black-hole fragments that might form during mergers.

Black holes with planets, too

Splitting isn't the only strange black hole idea in the news this month. Earlier in October 2026, astrophysicists Bhupendra Mishra and Wladimir Lyra discussed the possibility of black holes hosting their own planets on a SETI livestream.

Their simulations suggested a black hole could indeed have planets — potentially millions of them apiece, some growing larger than Jupiter.

Bottom line: Black holes sometimes collide and merge. A new theoretical study maps the rare conditions — extreme rotation, or extra spatial dimensions — under which one might instead split into two, though no such split has ever been observed.