Earth–Moon Gas Sphere Hypothesis: Subsurface Carbon–Silicon Mixed Resource Model

This work presents the Earth–Moon Gas Sphere Hypothesis: Subsurface Carbon–Silicon Mixed Resource Model, a unified framework for understanding hydrogen distribution, subsurface geochemistry, and volatile dynamics in the Earth–Moon system. The hypothesis proposes that the system is encompassed by a hydrogen-rich envelope extending to the lunar orbital radius (~300,000 km). In the present Earth, this hydrogen layer is masked by the strong chemical affinity of carbon (C), nitrogen (N), oxygen (O), and sulfur (S), which bind hydrogen into stable compounds such as water, ammonia, and hydrocarbons. In a hypothetical absence of these reactive species, the Earth would sustain a free molecular hydrogen atmosphere with a surface partial pressure of ~30 bar, effectively behaving as a dense hydrogen gas planet. The subsurface is modeled as a carbon–silicon mixed resource layer, incorporating primordial hydrocarbons, biogenic carbon, and abundant mineral admixtures (Si, Ca). This dual-origin composition links planetary formation chemistry with the shallow biospheric carbon cycle. Furthermore, the spatial anisotropy of hydrogen density in the outer shell is considered in the context of tidal potentials, with a mathematical form analogous to quadrupole corrections in Compton scattering angular distributions. The model integrates planetary-scale gas physics, tidal dynamics, and scattering analogies, providing a new perspective on volatile behavior in the Earth–Moon system and its observational signatures.