Part 5/8:
Penrose utilized the concept of spacetime geodesics—paths representing the movement of objects in gravitational fields. He revealed that within a black hole, not only do incoming null geodesics converge, but the outgoing ones also do, indicating that spacetime itself "ends" at these singularities.
His findings ushered in the concept of "geodesic incompleteness," which suggests that time or space could cease to exist beyond a singularity, compelling us to reconsider our understanding of reality itself. Before this, physicists held the assumption that spacetime was continuous and smooth, but Penrose opened the door to the idea that it could harbor cracks or gaps.