
We derive Newton's law of gravitation, Mercury's precession (42.99"/yr, Δ=0.02% vs GR), equinoctial precession (50.29"/yr, Δ=0.02% vs IAU), the Saros cycle, tidal locking, and the orbital resonance calibration law from a single entropic cross-coupling energy E_cross = −k_B Σ A_ij log(r_ij/r_0). P10 (tidal locking rule: e<0.1→1:1, e>0.1→3:2) is confirmed on 34/34 solar system bodies (p=5.8×10⁻¹¹). The correlation between resonance duration and precision gives r=−0.824, p=0.002 (N=11 pairs) — not predicted by Newtonian mechanics. Paper IV of five.
