Light Properties and Energy Density in the Inner and Outer Universe

This work is the third part of the five-paper series on the Cosmic Wave Equation. Series 3 explores the properties of light energy in the inner and outer universe. The inner universe is assumed to contain non-zero energy fluctuations, while the outer universe retains light-like properties despite zero local energy. By integrating both domains, the study extends the Cosmic Wave Equation to cosmological scales. This paper bridges the mathematical foundation of Series 2 with the physical interpretations in Series 4 and 5.