Big Bang as spacetime defect

In this paper, we review the suggestion that it is possible to eliminate the Big Bang curvature singularity of the Friedmann cosmological solution by considering a particular type of degenerate spacetime metric. Specifically, we take the four-dimensional spacetime metric to have a space-like three-dimensional defect with a vanishing determinant of the metric. This new solution suggests the existence of another “side” of the Big Bang (perhaps a more appropriate description than “pre-Big-Bang” phase used in our original paper). The corresponding new solution for defect wormholes is also briefly discussed.