How does a cyclical cosmology connect a big crunch to a later big bang?

In cyclical cosmology, the transition from a "big crunch" to a subsequent "big bang" is a theoretical mechanism proposed to address how a self-contained space-time might be created or destroyed, as current general relativity does not fully explain these processes.1

In this model, the big crunch—a hypothetical event where the universe collapses into a singularity due to sufficient matter density—would evolve into the big bang of a new, expanding universe. This transition is posited to occur through quantum gravity or other exotic physical processes that remain outside the scope of currently well-understood physics.21

While the standard big-bang model describes the evolution of our universe from a hot, dense state 13.8 billion years ago, cyclical theories suggest that our universe may be part of a larger, connected system where such collapses and expansions repeat. These models remain speculative, as they rely on physics that has not yet been empirically verified.134