The Hubble flow shows a residual dipole pattern beyond what local peculiar motion relative to the CMB rest frame can explain. Recession velocities exhibit systematic directional asymmetry persisting to large distances, with the dipole direction not perfectly aligned with the CMB dipole (Secrest 2021; Singal 2022). The signal challenges the cosmological-principle assumption underlying ΛCDM.
The standard model assumes a homogeneous-isotropic FLRW universe so that the Hubble flow appears uniform once local peculiar motion is subtracted. A persistent residual dipole at large distances must therefore come from unmodeled bulk-flow effects or from genuine large-scale anisotropy, neither of which has clean accommodation in the model.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, the Hubble flow dipole decomposes into two predicted geometric components. The first is a kinematic component of about 1.2 km/s/Mpc aligned with the CMB dipole, sourced by our patch's residual frame velocity within the parent frame (P63, P64). The second is a dynamical-Λ_eff component of 1.5 to 3 km/s/Mpc along the KBC supervoid axis, sourced by the spatial Λ_eff(x,t) gradient (P17, P19).
The two axes are geometrically required to be approximately perpendicular per P64 (J perpendicular to b, with v_frame parallel to b). Total combined amplitude of 3 to 6 km/s/Mpc matches the observed Hubble-flow dipole magnitude. The direction offset between the dipole and the CMB direction reflects the partial alignment of the kinematic and Λ_eff components, which combine vectorially rather than additively. Sibling-pocket gravitational influence at 1 to 2 Gpc separations (P58, P59, P60) adds a smaller third contribution.
Mesh dissipation (P14, P15, P16) gives slow redshift evolution of the dipole pattern as the Λ_eff field evolves between recombination and now (P18). The same M9 + M5 framework that produces dark flow (recid 12), the CMB dipole excess (recid 31), the galaxy distribution dipole (recid 77), and the local dipole anomaly (recid 91) produces the Hubble-flow dipole as one more observational projection of the multi-pocket cascade-geometry signature. There is no need to invoke unmodeled bulk-flow effects beyond cascade geometry.
If precision DESI + Euclid Hubble-flow analysis with full directional decomposition finds the residual dipole consistent with pure kinematic at the 0.5 km/s/Mpc level (no perpendicular Λ_eff component, no two-axis structure), the M9 + M5 cascade-geometry explanation is refuted. The signature SCT prediction is approximately 90-degree separation between the kinematic component (CMB dipole direction) and the Λ_eff component (KBC supervoid direction).