Black holes can not only swallow matter but also bounce off each other elastically, like billiard balls. Scientists set up a gravitational shooting gallery — and the scattering angle matched the theory to within a degree. In the future, such targeted tests of "hairy" holes will help find cracks in the foundation of general relativity.
🎯 Unlike slow accretion, black hole "hair" here grows almost instantly — within a couple of dynamical timescales. This makes them almost universal objects, carrying a memory of the field from birth.
🎬 In "Interstellar," Gargantua is a portal through time. Add a pervasive scalar field — and the black hole would grow "hair," becoming even more exotic, just like in this theory.