A Negative Correlation Between Dynamical Time and MOND Acceleration a0 in SPARC Galaxies

We investigate the correlation between the dynamical time scale t_dyn = 2πR/V and the per-galaxy MOND acceleration constant a0 for 134 spiral and irregular galaxies from the SPARC database. We find a statistically strong negative correlation (Spearman ρ = −0.443, p = 8.6×10⁻⁸). Extended analysis reveals: (i) t_dyn is a mathematical combination of R and V, not an independent variable; (ii) three causal-direction tests (ANM, HSIC, LiNGAM) support a0 → t_dyn; (iii) HI disc radius R_HI is a novel independent predictor (partial ρ = −0.521), improving R²adj from 0.25 to 0.584. This research note reports observed patterns to invite critical examination. No mathematical theoretical framework exists; independent verification is required.