Laniakea is a kinematic object: a 500-million-light-year basin of attraction holding 10¹⁷ solar masses, threaded by strands of correlated galaxy motion converging on the Great Attractor (Tully et al. 2014). The flow amplitudes run hot against ΛCDM, with bulk motions of 400 to 600 km/s toward Shapley at depths linear theory assigns percent-level probability, and basin volumes exceeding the simulated distribution. The velocity field is more organized than the model's initial conditions allow.
In the model, velocity coherence is borrowed from density: flows arise from gravitational responses to the matter field, with correlations dying at the initial power spectrum's large-scale cutoff. Velocity strands and basin flows exceeding those amplitudes have no source, because nothing in the model moves galaxies except the density field it already built.
SCT gives the velocity field its own ancestry: galaxies condensed from collision debris streams inherit the streams' bulk motion (P31, P32, P8), so velocity coherence is deposited alongside position rather than borrowed from density afterward. Laniakea's strands are the inherited stream pattern still flowing: tributaries of correlated motion tracing the deposition geometry (P34), with the basin's watershed structure the kinematic fossil of how the local debris field was laid down. Flow amplitudes exceed density-sourced expectations because part of the motion is original equipment, the residual bulk velocities of deposition (P63 at pocket scale), not gravity's later work.
The framework's registered statistics carry the tests: bulk flow directions should align with the local cosmic web's angular momentum axis within 30 degrees (the CosmicFlows-versus-filament-J prediction), coherent flow excesses should persist to gigaparsec depths where sibling-pocket influence enters as the secondary modulation (P59, P60), and redshift scatter should track shared parent-frame membership. The basin cartography ΛCDM struggles to house is, in SCT, the primary dataset for reading deposition history: cosmic forensics by velocity field.
This is the same inherited-motion physics behind the cold local flow and the satellite-plane kinematics, written at supercluster scale. There is no need to source watershed-scale coherence from a density field that cannot supply it.
The registered kill: CosmicFlows-class analyses finding bulk flow directions uncorrelated with the local web's J axis (no alignment within 30 degrees at better than 1σ after systematics), would break the inherited-stream reading. The amplitude side cuts equally: next-generation distance catalogs finding basin volumes and flow amplitudes fully consistent with ΛCDM linear theory would remove the excess coherence the deposition account exists to explain.