The Einstein theory of gravitation breaks down at very high curvatures. We propose a modification of the theory at Planck curvatures for which all isotropic cosmological solutions (even including matter) are nonsingular. All solutions asymptotically approach de Sitter space, a solution with limiting curvature.

• Received 11 December 1991

DOI:https://doi.org/10.1103/PhysRevLett.68.1969