Coherent bulk flows of galaxy clusters at roughly 600 km/s extending across hundreds of Mpc to ~1 Gly persist across surveys (CosmicFlows-4 confirms 400–600 km/s toward Centaurus-Vela). The amplitude is roughly twice ΛCDM peculiar-velocity predictions, persisting to scales where the cosmological principle should enforce isotropy (Kashlinsky 2008; Watkins 2009).
Beyond a few hundred Mpc the standard model assumes statistical homogeneity. Bulk flows must decay to zero on those scales because there are no large-scale structures outside our Hubble sphere to source coherent motion. A persistent ~Gpc bulk flow has no place to come from in a globally isotropic FLRW universe.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field that became our visible universe. From this single change, our patch is not an isolated FLRW universe. It is one component of a multi-pocket gravitationally coupled system created by the same parent-scale collision (P58, P59), with sibling pockets at separations of roughly 1 to 2 Gpc and recession velocities in the range 0.23c to 0.47c — subluminal, meaning the nearest siblings sit within our Hubble sphere and exert real gravitational influence on our patch.
The original collision also gave our patch a residual bulk velocity within its parent frame: v_frame ≈ v_rel(final) × (b/R_min), set by the cumulative cascade impact-parameter geometry (P63). This frame velocity is a permanent kinematic property of our patch, propagating coherently across the entire observable volume rather than being a peculiar-velocity contribution from late-time structure formation. Sibling-pocket gravitational influence and inherited frame velocity together produce the observed coherent bulk flow with no need for a Great Attractor that no longer attracts after correction or for a mysterious dark stream beyond the horizon.
The same mechanism that produces dark flow predicts that the flow direction should align with both the CMB dipole and (perpendicular to) the cosmic-web J-vector axis (P64), since the impact parameter b is perpendicular to the angular momentum J = μ(b × v_rel). DESI peculiar-velocity surveys plus Planck CMB-dipole measurements together provide a clean cross-check on the direction prediction.
If the next generation of bulk-flow surveys (4MOST, DESI peculiar velocities) finds the flow direction perpendicular to the predicted nearest-sibling direction (which should be roughly perpendicular to the J-coherence axis from quasar polarization or radio-jet alignment surveys), the M9 sibling-pocket attribution fails. Equivalently, if the flow amplitude decays to the ΛCDM peculiar-velocity prediction at the 1% level once peculiar-velocity systematics are fully cleaned, the M9 mechanism is refuted.