The reason why the energy of gravity doesn't cause everything to collapse into a single point or create a universe-sized black hole is a complex topic that involves the interplay of various factors. Here are a few key points to consider:
Expansion of the Universe: The universe is currently experiencing a phase of expansion, as supported by observations such as the redshift of distant galaxies. This expansion counteracts the gravitational pull between objects on large scales. The expansion of the universe is attributed to a phenomenon known as dark energy, which is thought to be causing the acceleration of this expansion.
Distribution of Matter and Energy: The matter and energy in the universe are not evenly distributed. On large scales, matter is distributed in a web-like structure known as the cosmic web, consisting of galaxy clusters, filaments, and voids. This uneven distribution creates gravitational interactions between objects, leading to the formation of galaxies, galaxy clusters, and other cosmic structures. The local gravitational effects dominate over larger cosmic scales, preventing a collapse into a single point.
Pressure and Internal Forces: Gravity is not the only force at play in the universe. Other fundamental forces, such as electromagnetic forces, nuclear forces, and the quantum mechanical effects of particle interactions, counterbalance gravitational collapse on smaller scales. In particular, pressure from these forces can resist gravitational compression, providing additional support against collapse.
Balance of Energy: The universe's overall energy balance also plays a role. For a black hole to form, matter and energy must be concentrated within a small region, leading to extreme gravitational forces. However, the observed energy content and density of the universe are not concentrated enough to create a universal black hole.
It's worth noting that our understanding of the universe's structure and the interplay between gravity, expansion, and other forces is based on current theories and observations. The nature of dark energy and the ultimate fate of the universe are still active areas of research, and ongoing scientific investigations continue to refine our understanding of these phenomena.