Chaotic Medium Cosmology II: A Screened Elastic Gravity Model for Galactic Rotation Curves

This repository contains the full manuscript and numerical implementation of Chaotic Medium Cosmology II (CMC II), a phenomenological modified gravity framework that interprets galactic-scale dynamical anomalies as an emergent elastic response of spacetime. CMC II models gravity as an effective interaction within a chaotic cosmic medium exhibiting screened elasticity. In regions of high acceleration (e.g., the Solar System), the elastic response is dynamically suppressed, recovering standard Newtonian gravity. In low-acceleration regimes characteristic of galactic outskirts, the medium transitions to an elastic phase, generating an additional acceleration term proportional to �, reproducing MOND-like behavior without invoking dark matter. The framework introduces a smooth logistic screening function that ensures consistency with Solar System constraints while naturally recovering flat galactic rotation curves and the baryonic Tully–Fisher relation. The model is tested against high-quality rotation curve data from the SPARC database, with a detailed fit to the galaxy NGC 3198, yielding an excellent reduced chi-squared value (�) using only baryonic mass distributions. Included in this repository are: The complete LaTeX manuscript suitable for journal submission A dimensional and mathematical consistency analysis Python code implementing the CMC II acceleration law and rotation curve fitting Figures and numerical results used in the study CMC II is formulated as a non-relativistic effective field theory applicable on galactic scales. Future extensions will address relativistic completion and cosmological implications.