A black hole is defined by its event horizon, which gives it a measurable size, while the singularity at its center, if it exists, is theorized to have no size. The complexities of spacetime curvature make it difficult to determine the actual volume of a black hole. Non-rotating black holes are considered perfect spheres with a radius equal to their Schwarzschild radius, while rotating black holes take on an oblate spheroid shape. The discussion highlights the contradictions in defining singularities, noting that while some are treated as mathematical points, others possess dimensions that complicate their classification. Overall, the nature of black holes remains a challenging topic in physics, intertwining quantum theory and general relativity.
