We present the Matter-Originated Spacetime Gradient Model (MOSGM), an effective modified gravity framework in which observed gravitational acceleration is related to baryonic acceleration through a spacetime-gradient-motivated interpolating function. The model contains no intrinsic free parameters in its functional form beyond the MOND acceleration scale (a0) and a normalization constant κ = (e−1)−1, with dependence on the stellar mass-to-light ratio as in standard rotation curve analyses. We evaluate MOSGM against the SPARC dataset of 171 galaxies and compare its performance with MOND under a consistent analysis pipeline. MOSGM achieves a median correlation of 0.959 and a median RMS residual of 14.63 km/s, compared to 0.958 and 13.98 km/s for MOND. The model exhibits a near-zero median bias (+0.20 km/s), compared to +4.20 km/s for MOND. MOSGM reproduces galaxy rotation curves with accuracy broadly comparable to MOND while introducing a structurally distinct spacetime-gradient formulation. A key limitation is identified in the deep-acceleration regime, where the model predicts declining rotation curves instead of asymptotically flat profiles. We present three parameter-free predictions, including a fixed normalization constant, a transition radius scaling relation, and a distinct outer-region behavior, providing clear avenues for observational falsification. This work establishes MOSGM as a phenomenological alternative framework for galaxy dynamics and motivates further theoretical development.
Tarun kumar saxena (Sat,) studied this question.