A Falsifiable Structural Cosmology with Linear-to-CMB Observational Closure Without Dark Sectors

This work presents a fully testable cosmological framework in which gravitational dynamics emerge from baryonic structure, without invoking dark matter or dark energy as independent components. A single structural parameter governs the effective gravitational response and is constrained across independent observables. The model is evaluated consistently from linear structure growth to the full CMB temperature and polarization spectra, including the Integrated Sachs–Wolfe effect, lensing, and global likelihood. The framework achieves observational closure: it preserves the acoustic structure of the CMB and high-multipole consistency, while introducing controlled late-time modifications that improve agreement at large angular scales. A universal structural threshold is recovered across all sectors, indicating a common geometric origin of galaxy-scale and cosmological-scale dynamics. Crucially, the model is falsifiable. It makes concrete, testable predictions across growth, CMB anisotropies, and lensing observables, allowing direct validation or rejection with current and future precision data. This work establishes a minimal, internally consistent alternative to standard cosmology, demonstrating that a unified structural mechanism can reproduce key observables without introducing unseen components.