Size of the universe before the big bang
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Early Universe Size in Pre-Big Bang and Inflationary Cosmology
Research on the size of the universe before the Big Bang, especially in pre-Big Bang (PBB) and inflationary scenarios, shows that the universe may have needed to be extremely large and homogeneous from the very beginning. In the PBB scenario, the homogeneous region at the onset of inflation must be larger than 10^19 times the string length (ls), which is the fundamental length scale in string cosmology. For a closed universe, this means uniformity over at least 10^24 causally disconnected domains, and for an open universe, homogeneity would need to extend over infinite distances. These requirements suggest that the universe was already vast before inflation began, challenging the idea that inflation alone solves the problem of the universe’s large-scale structure and uniformity .
Quantum Big Bang Theory and Early Universe Size
Alternative models, such as the Quantum Big Bang theory, propose a much smaller initial size for the universe. According to this theory, when the universe entered the classical Friedmann-Robertson-Walker (FRW) phase, its size was about 0.2 centimeters. This model also suggests that classical inflation is not necessary to explain the observed properties of the universe, as the required density contrasts and scale invariance arise naturally .
Alternative Cosmological Models and Initial Universe Size
Other cosmological models, such as Liu’s Cosmological Model, describe the universe at its birth as a massive neutron with a radius of approximately 4.8 × 10^11 meters (about 480 million kilometers). This model suggests that the universe started at rest and expanded rapidly due to the release of heat energy, with the Big Bang occurring shortly after this initial state 34. These models provide a much larger initial size compared to the Quantum Big Bang theory, but still differ significantly from the requirements of the PBB scenario.
Mythological and Conceptual Perspectives
Some perspectives, inspired by mythology, describe the universe’s origin as emerging from a “Cosmic Egg” or singularity, with the triggering of the Big Bang linked to a specific size or condition, such as the golden ratio. While these ideas are more conceptual, they highlight the ongoing search for a deeper understanding of what set the initial conditions for the universe’s expansion .
Observable Universe and Beyond
Current observations allow us to see a universe about 93 billion light-years in diameter, but some theories suggest the actual universe could be much larger than what we can observe. The gravitational influence of the Big Bang and the possibility of the universe being part of a larger cosmological structure are also considered in some models, indicating that the true size of the universe at or before the Big Bang may be far greater than the observable portion .
Conclusion
The size of the universe before the Big Bang is still a subject of debate and depends heavily on the cosmological model considered. Some theories require an already enormous and homogeneous universe before inflation, while others propose a much smaller initial size. There is no single consensus, but research continues to explore these fundamental questions, seeking to clarify the universe’s earliest moments and its true scale 1234+2 MORE.
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