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Electromagnetic absorption in planetary materials fundamentally governs the penetration depth, attenuation behavior, and energy deposition of radiation across atmospheres, surfaces, and deep interiors. Although the underlying physical principles—rooted in Maxwell’s equations, radiative transfer theory, and experimentally measured absorption coefficients—are well established, their application to real planetary systems remains fragmented, particularly when accounting for dynamic evolution and stratified structure. This work presents a unified, quantitatively rigorous framework that consolidates spatial attenuation, energy deposition, dimensionless optical response (absorbance and optical depth), time-dependent material evolution, and multi-layer stratification into a single coherent formulation. The framework is derived entirely from first-principles radiative-transfer theory, without introducing new physical laws or empirical assumptions, ensuring full compatibility with laboratory spectroscopy, atmospheric modeling, and planetary geophysics. A key contribution of this study is the explicit formulation of a practical rate-based expression for electromagnetic absorption, Absorption Rate= α I dx/dt, which directly links radiative attenuation to material evolution processes such as sedimentation, compression, accretion, and phase transitions. This formulation provides a physically interpretable, dimensionally exact metric for local energy deposition in non-static planetary media and enables direct implementation in numerical models of planetary evolution. Quantitatively, the framework demonstrates that even moderate absorption coefficients (α∼1–10 m−1), when integrated over realistic planetary path lengths and layered structures, produce optical depths (τ≫1) sufficient to reduce transmitted intensity to negligible levels. In conductive or mineral-rich environments, higher absorption regimes (α≥102–105 m−1) further restrict electromagnetic penetration to millimeter–centimeter scales. As a result, planetary interiors spanning kilometer to planetary-radius scales are inherently radiatively opaque, independent of observational technique. The unified multi-layer formulation, I=I0exp(−∑iαixi) demonstrates that cumulative optical depth increases rapidly even when individual layers exhibit moderate absorption, providing a rigorous explanation for the universal limitation of electromagnetic probing of deep planetary interiors. Crucially, the framework establishes that electromagnetic attenuation is not merely a constraint on observation, but a fundamental mechanism of energy transfer. The absorbed component, Iabs=I0(1−e−τ) represents the continuous conversion of radiative energy into internal energy, contributing to thermal gradients, phase transitions, and chemical processes within planetary materials. This has direct implications for planetary thermal evolution, climate regulation, and subsurface habitability. A central interpretive result of this work is that the absence of detectable electromagnetic signals from planetary interiors cannot be taken as evidence of inactivity. Instead, it reflects the unavoidable consequence of high optical depth and material opacity. This clarification resolves a persistent ambiguity in planetary science and reinforces the distinction between observational limitations and physical absence. By systematically integrating established radiative physics into a unified and dynamically consistent framework, this study enhances the accuracy, interpretability, and cross-disciplinary consistency of planetary modeling. The resulting formulation is fully testable, dimensionally rigorous, and applicable across scales ranging from laboratory samples to entire planetary bodies, providing a robust foundation for future research in planetary science, radiative transfer, and subsurface exploration. Please check the attachment for details