Towards a Physical Alternative to Dark Matter: The Hypothesis of Cosmic Deserts and Boundary Reflections in Spacetime

This paper introduces the Space-time Topographical Constitution (STC) model, a novel conceptual framework positing that dark matter phenomena arise not from undetected particles but from intrinsic variations in the elasticity of spacetime fabric. The model bifurcates the universe into ``spacetime clouds'' with high intrinsic curvature facilitating matter condensation and ``cosmic deserts'' with flat geometry inhibiting mass accumulation. Furthermore, it reinterprets the Cosmic Microwave Background (CMB) as an energy reflection from a terminal spacetime boundary. Rigorous mathematical derivations, including detailed geodesic, perturbation, and topological analyses, Python-based simulations incorporating real cosmological data from Planck and SDSS, advanced sensitivity analyses, Bayesian inference, quantitative statistics, and a dedicated statistical analysis section support the model. Engineering formulations for laboratory analogs are provided, alongside a manufacturing roadmap for experimental verification. Observational evidence from SDSS voids, JWST early galaxies, Planck CMB anomalies, and recent 2023-2025 studies on cosmic voids and CMB anomalies is extensively integrated, with falsifiability criteria emphasized. This conceptual paper is self-contained, with all data, derivations, and simulations included.