Field Transition Magnetism (FTM) introduces a radical substitution in gravitational theory: replacing mass density with coherence density in both Newtonian and Einsteinian frameworks. This substitution not only preserves predictive success but also reveals hidden couplings between magnetism, coherence, and planetary dynamics. First, the tether experiment provides direct laboratory evidence of anomalous force interactions when conductive tethers traverse Earth’s magnetic field. These anomalies, long treated as engineering curiosities, are reframed here as coherence density transitions — the first empirical proof of FTM’s validity. Second, by embedding coherence density into the Poisson equation and Einstein field equations, FTM successfully predicts the poleward migration of solar magnetic flux. Traditional dynamo models struggle to explain this phenomenon, but FTM derives it naturally as coherence redistribution along solar gravity lines. This breakthrough allows us to calculate orbital velocity and escape velocity using coherence density substitution, demonstrating dimensional clarity and predictive robustness across classical mechanics. Third, FTM extends beyond stellar magnetism to planetary volcanism. By modeling coherence density as the driver of internal heating, FTM predicts the onset, persistence, and cessation of volcanic activity across planetary bodies. Mercury and Mars, once volcanically active, entered dormancy when their rotations synchronized with orbital resonance, ceasing to cut solar gravity lines. Fourth, FTM provides a compelling explanation for Venus’s immense volcanic activity, including its estimated 1,800 active volcanoes. Venus’s retrograde rotation continuously cuts solar gravity lines, sustaining internal heating through coherence redistribution. Fractional perturbations from quasi‑satellite Zoozve further amplify this resonance, offering a coherence‑based source for Venus’s extraordinary volcanism. Finally, FTM generalizes to all planets, predicting volcanic activity as a direct consequence of coherence density interactions with solar gravity lines. This framework unifies planetary volcanism, stellar magnetism, and orbital mechanics under a single principle, challenging the entrenched reliance on mass‑based gravity. In summary, FTM is not a speculative reformulation but a demonstrable breakthrough: tether anomalies prove coherence transitions, solar poleward flows validate coherence redistribution, and planetary volcanism confirms coherence‑driven heating. Together, these results establish coherence density substitution as a viable successor to Newtonian and Einsteinian mass‑gravity equations, opening a new era of predictive astrophysics and planetary science.