A Parameter-Free Prediction of the Dark Energy Fraction from the U-Cell Model

Ω_Λ We derive a parameter-free prediction for the dark energy fraction from the U-Cell Model (UCM) via a plate-tectonics analogy for cosmic structure formation. Voids create new substrate cells at the Hubble rate H0, while halos absorb substrate at the orbital angular frequency, which is universal and independent of the individual galaxy's rotation speed. The steady-state balance yields OmegaLambda = sqrt (2) / (sqrt (2) + sqrt (2 - pi/2) ) = 0. 6834, in agreement with Planck 2018 (OmegaLambda = 0. 6847) to 0. 19%. Because H0 cancels in the balance, the prediction holds for all redshifts, corresponding to a dark energy equation of state w = -1 exactly. The single UCM constant fcold = sqrt (2 - pi/2) simultaneously governs the galactic MDAR acceleration scale g† = fcold⁴ · c · H0 and the cosmic energy budget, providing the strongest internal consistency test of the model. No free parameters are introduced.