{"id":804171,"date":"2026-11-01T07:57:34","date_gmt":"2026-11-01T12:57:34","guid":{"rendered":"https:\/\/spaceweekly.com\/?p=804171"},"modified":"2026-11-01T07:57:34","modified_gmt":"2026-11-01T12:57:34","slug":"do-black-holes-split-into-smaller-black-holes","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=804171","title":{"rendered":"Do black holes split into smaller black holes?"},"content":{"rendered":"
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\nCan a black hole split into 2 or more smaller holes? A new theoretical study says it\u2019s possible. But it probably happens only if the original black hole is spinning really fast. Artist\u2019s concept via LIGO\/ Caltech\/ Simulating eXtreme Spacetimes Collaboration. Used with permission.<\/figcaption><\/figure>\n<\/div>\n
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Black holes can sometimes collide and merge.<\/strong> But can they split into two?<\/li>\n
A new theoretical study<\/strong> from the University of Southern Denmark says it\u2019s possible, but only under certain specific circumstances.<\/li>\n
Extremely rapid rotation might allow a black hole to split<\/strong>. But even then, the conditions would have to be just right.<\/li>\n<\/ul>\n
Science news, night sky events and beautiful photos, all in one place.<\/em> Click here to subscribe to our free daily newsletter.<\/strong><\/p>\n
Could black holes split into 2 or more?<\/h3>\n
We think of a black hole as a solitary object, drifting through space or lurking at the crowded center of a galaxy. Black holes do sometimes collide, though. Sometimes they merge together to make a more massive<\/em> black hole.<\/p>\n
But could the reverse happen? Could a black hole split apart and become two or more smaller<\/em> ones? Researchers at the University of Southern Denmark investigated this possibility in an intriguing new theoretical study published in the peer-reviewed journal Physical Review D<\/em> on October 22, 2026. They said that under most conditions, splitting black holes aren\u2019t likely.<\/p>\n
But theory suggests splitting might happen under certain circumstances, particularly if a black hole is spinning extremely rapidly. Francesco Sannino is a co-author of the study and a professor of physics at the University of Naples Federico II in Italy and the Quantum Field Theory Center at the University of Southern Denmark. He explained:<\/p>\n
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In our study, we investigate which physical laws normally prevent a black hole from splitting into two. We also investigate if certain circumstances may allow a split to happen.<\/p>\n<\/blockquote>\n\n
What typically prevents splitting? Entropy<\/h3>\n
So far, there\u2019s no evidence that black hole splits happens in nature. Astronomers haven\u2019t yet found any black holes that appear to have split yet. But it\u2019s a big and varied universe out there. Why can\u2019t<\/em> a black hole split?<\/p>\n
The answer has to do with entropy. To physicists, entropy is a property of a physical system related to the number of microscopic arrangements that produce the same overall state.<\/p>\n
In simple terms, entropy helps physicists understand which changes can happen spontaneously and which are energetically or thermodynamically unfavorable.<\/p>\n
So think of a single black hole as a system with entropy. If a black hole weren\u2019t rotating, splitting it into two smaller black holes would reduce the system\u2019s total entropy. But the second law of thermodynamics says that the total entropy of an isolated system cannot<\/em> decrease in a spontaneous process.<\/p>\n
So a black hole splitting in two would run counter to a fundamental law of physics.<\/p>\n
\nIllustration of a black hole splitting into 2, in the shape of a pair of pants. This is called \u201cpair-of-pants topology.\u201d Image via Francesco Sannino\/ EurekAlert!.<\/figcaption><\/figure>\n<\/div>\n
Rapidly spinning black holes<\/h3>\n
But rotation could change the picture. A rapidly spinning black hole has energy associated with its rotation, which affects the conditions under which it might split. Under the right theoretical conditions, one black hole could branch into two or more smaller black holes.<\/p>\n
Scientists describe this change in shape as a pair-of-pants topology<\/em>. Imagine the shape of a pair of pants: one opening at the top branches into two legs below. In this analogy, the original black hole gives rise to two separate black holes. <\/p>\n
But there\u2019s a catch. The two new black holes must be able to move apart rather than fall back together. As Sannino explained:<\/p>\n
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When we include this requirement, the window largely closes again, except possibly for black holes rotating close to their maximum possible rate.<\/p>\n<\/blockquote>\n
Exotic hypotheses<\/h3>\n
There are more exotic possibilities, too. These remain purely theoretical, at least for now.<\/p>\n
Some theories propose that our universe has additional spatial dimensions beyond the three we experience (up and down, back and front, side to side). If these extra dimensions exist, black holes might behave in unexpected ways. In higher-dimensional models, some black holes can become unstable and begin to break apart.<\/p>\n
In such models, the researchers found, splitting could become much more likely. The total entropy could increase rather than decrease, making the split thermodynamically favorable. But there are still a lot of unknowns. Sannino said:<\/p>\n
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We cannot yet give a single probability for a black hole to split. It depends on how gravity behaves beyond Einstein\u2019s theory, and we are working to quantify this. We expect small primordial black holes [hypothetical, miniature black holes theorized to have formed in the first fraction of a second after the Big Bang] to be more prone to splitting than much larger astrophysical black holes. <\/p>\n
We may detect a split indirectly: gamma-ray telescopes such as Fermi-LAT can search for signals from tiny black-hole fragments that might form during mergers.<\/p>\n<\/blockquote>\n
Black holes could have planets, too<\/h3>\n
Earlier this month, astrophysicists\u00a0Bhupendra Mishra\u00a0and\u00a0Wladimir Lyra discussed the possibility of a black hole having its own planets, on a SETI livestream.<\/p>\n
Simulations suggested that a black hole could indeed have planets. And those planets could number in the millions for each one, and grow larger than Jupiter. Wow!<\/p>\n
Bottom line: Black holes sometimes collide and merge. Could one split into two or more? A new theoretical study explores the conditions that might allow it, including extremely rapid rotation and more exotic possibilities involving extra dimensions.<\/p>\n
Source: When black holes admit pair-of-pants topologies<\/p>\n
Via University of Southern Denmark<\/p>\n
Read more: Astronomers discover a black hole star, a new type of object<\/p>\n
Read more: A black hole jet is aimed at us \u2026 and it\u2019s in our galaxy<\/p>\n
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Paul Scott Anderson<\/h4>\n
View Articles\n <\/p><\/div>\n
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About the Author:<\/h6>\n
Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan\u2019s Cosmos. He studied English, writing, art and computer\/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.
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\nWhile interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.
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\nHe has been writing for EarthSky since 2018, and also assists with proofing and social media.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n
![\"Y-shaped](\"https:\/\/earthsky.org\/upl\/2026\/10\/black-hole-split-pair-of-pants-topology-Francesco-Sannino-October-23-2026.jpg\")