Is a black hole a sphere or a funnel?

Verification: This corrects a common misleading picture but needs qualification. For an idealized nonrotating black hole, the event horizon is a spherical boundary of no return. A funnel is a way to depict curved space on a two-dimensional diagram, not the black hole’s actual shape. Real astrophysical black holes rotate; their spacetime has axial symmetry, and its geometry cannot always be reduced to an ordinary ball in Euclidean space. A black hole also is not a solid spherical surface.

Conclusion: The horizon of a nonrotating black hole is spherical; the “funnel” is a visualization of curvature, not its shape. Rotating black-hole geometry is more complex.