Stability of black holes in general relativity
Establish whether stationary black-hole solutions in four-dimensional vacuum general relativity—particularly the Kerr spacetime—are stable under generic gravitational perturbations at both the linear and nonlinear levels, to clarify the long-term behavior of astrophysical black holes.
References
Nevertheless, there are open questions associated to BHs, such as their stability [21-24], the existence of singularities inside their event horizon [25], and Hawking's information-loss paradox [26, 27].
— Black Hole Spectroscopy and Tests of General Relativity with GW250114
(2509.08099 - Collaboration et al., 9 Sep 2025) in Introduction