Transition Cosmology: Saturated Primordial Node Dynamics, Resolution of Cosmological Tensions, and Observational Constraints

This research presents the of Environmental Transition Cosmology (ETC), a singularity-free cosmological model built upon primordial saturated nodes, hydrodynamic boundary transitions, and emergent large-scale spatial flatness (k=0k=0k=0). By resolving the foundational mechanics of energy confinement and hydrodynamic saturation (ρ≤ρsat\rho \le \rho_{\text{sat}}ρ≤ρsat), the ETC model simultaneously addresses major cosmological puzzles including the Hubble tension (H0H_0H0), the S8S_8S8 growth anomaly, early massive galaxy formation observed by JWST, and acoustic horizon freezing—providing a robust alternative without invoking dark energy. The formalism incorporates rigorous turbulence bounds, environmental tunnel parameters Γ(z)\Gamma(z)Γ(z), and verified numerical benchmarks.