The concept of a "Cosmic Crunch" refers to a hypothetical scenario in which the expansion of the universe reverses and leads to a collapse, resulting in a high-density state. This scenario is an alternative to the widely accepted idea of the universe's expansion continuing indefinitely.
However, based on our current understanding of the universe, the observational evidence suggests that the expansion of the universe is accelerating rather than slowing down or reversing. This discovery was made in the late 1990s and is attributed to a mysterious form of energy called dark energy. Dark energy is thought to permeate space and drive the accelerating expansion of the universe.
In the context of your question, the concept of a "Causality Event Horizon" is not well-defined in the context of the universe as a whole. The notion of an event horizon typically applies to black holes, where the gravitational pull is so strong that nothing, including light, can escape from within a certain radius. However, when considering the universe as a whole, the concept of a causality event horizon is not applicable in the same way.
It's worth noting that our understanding of the universe is based on current observations and theoretical models, which are subject to revision as new data and insights emerge. While a "Cosmic Crunch" scenario cannot be definitively ruled out, the current evidence supports the idea of ongoing expansion driven by dark energy.