Surviving from a journey into a black hole
Research Fellow, FCT, Institute of Astrophysics and Space Sciences (IA), Lisbon University, Portugal
Black holes are believed to be the end-state of gravitationally collapsed stars of enough mass, whose existence is predicted by General Relativity. According to this same theory, a hypothetical spacecraft journeying towards the innermost region of a black hole would end its existence once the central singularity is reached in finite affine time. In this talk I will present an extension of General Relativity which includes further contributions of scalars built out of the Ricci tensor and formulated in metric-affine spaces, where metric and affine connection are independent entities. In this formalism, the corresponding theories are compatible with solar system experiments and with gravitational wave observations out of BH-BH and NS-NS mergers. Using some of these theories, I will discuss the fate of light rays and extended observers as they get close to the central singularity, using geodesic completeness, tidal forces, scattering of waves, and accelerated motion, finding that they can go through the black hole. These results allow one to rethink some of the assumptions usually made about these classically problematic regions.
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