When a Black Hole Can Split Apart ⚡ экспресс
We investigate conditions under which black hole fragmentation—the splitting of the horizon into several smaller ones—may occur. Within classical general relativity, the Bekenstein–Hawking area law prohibits such processes for Schwarzschild black holes. For rotating Kerr black holes, kinematic constraints imposed by the relative positions of the horizons forbid fragmentation even in regimes where entropic considerations might allow it, except possibly for near-extreme rotation. We then consider scenarios permitting a 'pair of pants' topology: from the well-known Gregory–Laflamme instability in higher dimensions to effects of superradiant instability under non-axisymmetric confinement of radiation, and finally to gravity models that modify the relation between entropy, horizon radius, and mass in four dimensions. In all these cases, emission of small fragments can be entropically favorable, but its realization depends on the kinematic configuration of the initial state.
A black hole is like a spinning drop of viscous liquid. Normally, such a drop tends to stay whole: splitting would reduce its surface area, which contradicts the law of non-decrease of entropy (a measure of disorder, like a broken cup doesn't glue itself back together). For non-rotating black holes, discovered by Karl Schwarzschild, splitting is impossible. However, with furious rotation, centrifugal forces stretch the black hole, and a microscopic fragment can pinch off. This process resembles nuclear fission in the liquid-drop model. Physicists have also considered worlds with extra dimensions, where spacetime curvature behaves differently, and black holes can become unstable, like long liquid threads ready to snap into pieces. Such decay could alter the population of primordial black holes, born in the young Universe.
🎯 Merging black holes, on the contrary, always increases the total area—this process resembles the merging of mercury droplets and is accompanied by powerful [tag:gravitational_waves]gravitational waves[/tag].