Spacetime Inverse Version 2: A 5D Cyclic Gravity Model with Reductive Zero Transit

We present Spacetime Inverse Version 2, a 5D brane-world model where the 4D universe undergoes a complete, closed cycle between a negative gravity phase and a positive gravity phase through a reductive zero gate. The model modifies Newtonian gravity with three terms: a mass-dependent Yukawa correction, an energy dissipation factor, and a density-dependent 5D coupling. Using Earth flyby anomalies and internal heat flow as calibration, we find α = 0.06066, r_c = 1120 km, δ = 0.12. The model unifies short-range gravity anomalies, planetary heat budgets, dark energy, and stellar evolution under one framework. Three falsifiable predictions are provided for cosmological acceleration, planetary cooling reversal, and orbital anomalies.