Volume of the universe
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Understanding the Volume of the Universe
Volume Expansion in Inhomogeneous Universes
The volume expansion of the universe is influenced by its inhomogeneities. Studies using the Swiss-Cheese universe model, which is an exact solution of Einstein's equations, reveal that inhomogeneities can slow down the volume expansion compared to a homogeneous Einstein-de Sitter universe. When these inhomogeneities are small fluctuations, the volume expansion rate approaches the background value asymptotically. However, if the inhomogeneities are significant, the volume can be either smaller or larger than the background value, though there is an upper limit to this expansion1.
Finite vs. Infinite Volume
The total volume of the universe can be either finite or infinite, depending on its spatial curvature. Current cosmological data suggest that the universe is nearly flat, which implies a lower limit on the total volume. The observable universe, defined by the particle horizon, consists of multiple patches of similar volume to our own. Based on the latest data from the Wilkinson Microwave Anisotropy Probe (WMAP), there are at least 21 observable patches of the universe similar in volume to ours, with a potential upper limit of around 105 patches2.
Mathematical Models and Volume Calculations
Mathematical models of the universe, such as those based on the theory of volume numbers, describe the universe as a continuous, infinite, and eternal entity, though discrete in observation. These models help in understanding the complex interactions between energy, information, and time, which influence the universe's volume3. Additionally, the Friedmann universe model provides a mathematical framework for calculating the maximum volume of a closed universe, which is shown to be 2π²R³(t) at any cosmic time t7.
Observable Universe and Horizon Volume
The distribution of mass and energy within the universe's horizon volume changes over time. Initially, radiation mass dominates, followed by matter, and eventually dark energy becomes predominant. These changes affect the universe's horizon volume, which shows significant variations due to the transition from flat to curved and then closed space8. The concept of a "small universe" suggests that we might live in a compact flat universe with a volume of approximately 5 × 10³ Gpc³, as indicated by the analysis of cosmic microwave background radiation data9.
Large-Scale Structures and Local Volume
The local volume of the universe, as revealed by the Cosmicflows-3 catalog, includes large filamentary structures such as the South Pole Wall. This structure, extending across a significant portion of the local volume, highlights the complexity and vastness of the universe's large-scale features10.
Conclusion
The volume of the universe is a complex and multifaceted concept influenced by inhomogeneities, spatial curvature, and the distribution of mass and energy. Mathematical models and observational data provide insights into the finite or infinite nature of the universe's volume, the observable patches within it, and the large-scale structures that define its local volume. Understanding these aspects is crucial for a comprehensive grasp of the universe's expansion and overall structure.
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Volume expansion of a Swiss-cheese universe
Inhomogeneities slow down the volume expansion of the universe when viewed as small fluctuations, but the expansion rate approaches the background value asymptotically.
HOW MANY UNIVERSES DO THERE NEED TO BE
There are at least 21 universes with the same volume as ours, but we cannot know the number of observable universes beyond 105 patches.
GENERAL BASES OF THE PHYSICAL AND MATHEMATICAL MODEL FOR VOLUME UNIVERSE
The physical and mathematical model of the three-dimensional Universe, developed on the basis of the theory of volume numbers, is a self-realization of the singular point of the "Emptiness" in the energy-information-time field, with evolutionary processes caused by the influence of both the past and future on the past.
The Mass of the Universe
The mass of the universe is approximately 2.55 1049 tons, which is close to the weight of the universe calculated on the basis of stars.
Reconstructing the universe
Nonperturbative quantum gravity has a large-scale limit in which spacetime is four and the universe behaves semiclassically, revealing highly nonclassical aspects and a fractal structure of constant time slices.
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