Existence is the most fundamental concept for definitions and can be perceived as presences in transformation in space through interactions, attesting to the temporal dimension; based on this existential foundation, the Universe, which exists and contains everything, can be considered unique because it has nothing around it to interact with; thus, its existence or transformation, currently represented by its expansion, is defined by the interactions between its components, the variation of entropy and the search for a state of complete uniformity or without energy concentrations; considering that universal evolution can continue as long as there is mass (concentrated energy) and space for dispersion, the most extreme states of expansion and contraction are modeled, revealing a existential continuity in a continuous time. To clarify this perspective, the Standard Model, which considers 3D Space, is supplemented by the concepts of rest mass energy and vanishing dimensions. After considering and interweaving data and principles already presented in other studies, the addition or differentiation of this study is to present a cause for the beginning of the current expansion of the Universe and to improve the understanding of the process of existential evolution.