Space is so warped that it can actually stop 'black strings' from snapping apart like a stream of water from a tap.
arXiv · March 16, 2026 · 2603.12332
Why it matters
In general relativity, a 'black string' is a high-dimensional black hole that looks like a line. Usually, these are unstable and should pinch off into a series of smaller black holes (like water droplets), but this study proves that the background curvature of space can act as a cosmic stabilizer, allowing these massive strings to exist forever.
From the abstract
We show that spacetime curvature alone can classically stabilize black strings. Working within a consistent five-dimensional dilaton-gravity system with a flat brane, we find that sufficiently large black strings are classically stable when they extend from the brane to a timelike boundary, which may be either regular or conformal. Black strings are also classically stable in the critical case of the linear dilaton spacetime. In some of the curved backgrounds considered, black strings are stable