Photonic Universe Hypothesis (PUH) Applies the bow-front lattice-tear mechanism (Bow-Front Tear Capstone) to Earth's absolute motion through the cosmos, deriving a specific, falsifiable, closure-free prediction for detecting a terrestrial Planck core (candidate mass ~5 x 10^21 kg; Earth Convergence Paper). POSTULATE (stated openly, and tested by the prediction): the rest frame of the E8 / Super Polariton Field substrate is the cosmic rest frame in which the CMB dipole vanishes. Natural within PUH because the lattice and the CMB are two aspects of the same substrate (T178, T179). Under this postulate, Earth's steady absolute motion through the substrate is the measured CMB dipole: the Solar System barycentre moves at 369 +/- 0.9 km/s toward galactic coordinates (l,b) = (264.0, 48.3) deg, in Leo. A Planck core moving through the lattice concentrates tension in a bow front ahead of motion (tearing, T206 reverse cascade) and leaves a relaxation wake behind. So the terrestrial core's bow front points permanently toward Leo (the CMB-dipole apex); the wake trails toward the antipodal cold pole. PREDICTION: a deep-Earth emission/thermal asymmetry, enhanced on the leading (Leo-facing) hemisphere of the core and suppressed in the trailing wake, FIXED IN INERTIAL SPACE. Discriminating signature is PERIODICITY: because the direction is fixed in space while Earth rotates beneath it, the signal modulates on the SIDEREAL day (23h56m) and sidereal year, not the solar day — a fingerprint no i