The Hubble Tension Dissolved H0(local)/H0(CMB) = 13/12 from the Projective Plane over F3

The Hubble tension—the persistent ∼ 5σ discrepancy between local (H0 ≈ 73 km/s/Mpc)and CMB-derived (H0 ≈ 67.4 km/s/Mpc) measurements of the Hubble constant—is the mosturgent crisis in modern cosmology. We show that the ratioH0(local)/H0(CMB) = 13/12, where 13 = |P2(F3)| is the number of points in the projective plane over F3 and 12 = π(9)/2 is half the Pisano period. The predicted ratio 1.083 matches the observed 73.0/67.4 = 1.08309 to 0.02%. The tension is not a measurement error—it is the lattice correction that ΛCDM does not model. We connect 13 to the Weinberg angle (sin2 θW = 3/13 at MZ ) and the Hamming code 13, 10, 33.