The Einstein–Cartan theory extends general relativity by removing a constraint of the symmetry of the affine connection and regarding its antisymmetric part, the torsion tensor, as a dynamical variable.
The minimal coupling between torsion and Dirac spinors generates a repulsive spin-spin interaction which is significant in fermionic matter at extremely high densities.
Instead, the collapsing matter reaches an enormous but finite density and rebounds, forming the other side of an Einstein-Rosen bridge, which grows as a new universe.
Shockwave cosmology, proposed by Joel Smoller and Blake Temple in 2003,[7] has the “big bang” as an explosion inside a black hole, producing the expanding volume of space and matter that includes the observable universe.
[7] A related theory proposes that the acceleration of the expansion of the observable universe, normally attributed to dark energy, may be caused by an effect of the shockwave.