The Structural Edge of the Universe An Electron-Calibrated Limit at 3.87×10^11 Light-Years

This paper extends Yuuki Theory (Yuuki Collapse Theory) to a cosmological scale, proposing that the "size" of the universe is defined not by causal horizons or expansion age, but by a "limit of structural coherence". It explores how far physical structures can be meaningfully defined when using the electron as a universal mass ruler. Key Concepts of the Theory Boundary as Structural Sustainability: The edge of the universe is defined as the point where the electron-based mass calibration unit m_0 becomes too dilute to function as a meaningful ruler. Calculated Radius of the Universe: By applying Yuuki Collapse scaling laws to structural integration, the theory derives a maximum structurally sustainable radius of approximately 387 billion light-years (3.87 \times 10^{11} ly). Consistency with CMB: This structural edge lies far beyond the last scattering surface of the Cosmic Microwave Background (CMB) and does not violate current observations of isotropy or power spectra. Shift in Physical Interpretation: The "edge" is not a physical wall or singularity, but rather a normalization limit. Beyond this boundary, concepts such as "mass," "energy," and "distance" can no longer be coherently defined using electron-based units. Conclusion The paper concludes that while the universe may be unbounded in its geometry, it is structurally finite. By linking the "electron ruler" of particle physics directly to cosmology, Yuuki Theory provides a unified foundation for both the fundamental forces and the large-scale structure of the universe.