Which cosmic phenomenon is theorized to occur when the Universe stops its expansion and begins to contract?

The Big Crunch

The Big Crunch is a fascinating cosmological theory that predicts a possible final fate for the Universe: if the density of the Universe is high enough, gravitational force would overcome cosmic expansion, leading the Universe into a phase of contraction. This ultimate contraction could culminate in an extremely dense and hot state, similar to the initial state of the Big Bang, potentially starting an eternal cycle of expansion and contraction. The idea of an oscillating Universe challenges the imagination and highlights the beauty and complexity of cosmological theories that attempt to understand our place in the vast cosmos. Although the current consensus suggests that the Universe's expansion is accelerating, making the Big Crunch less likely, the exploration of these concepts continues to enrich our understanding of the Universe.