Einstein introduced Λ cosmological constant in 1917 to hold the universe static. When Hubble proved the universe was expanding, Einstein removed it, calling it his "biggest blunder. " A century later, standard cosmology revived Λ as dark energy, a mysterious force accelerating expansion; Einstein vindicated, but for a different reason. This note completes the arc: there is no dark energy nor mysterious force. Λ is the ground-state modal realization on the cosmic boundary; the geometry of the universe itself driving expansion. Einstein was right the first time, for reasons then unknown. The Möbius surface selects half-integer modes; the lowest yields the modal realization Λₜop · ℓP² ≈ 2Ω⁻¹. The observationally inferred Λₒbs differs by an inherent factor of 3/2 when converting from 2D surface to 3+1 spacetime. Prediction: 3. 0 × 10⁻¹²². Observed: 2. 84 × 10⁻¹²². Agreement: ~5%. No free parameters. v4 update: 3/2 factor is fleshed out with a proper Gauss-Codazzi embedding derivation.
Blake Shatto (Sat,) studied this question.