Branching Vorticity Flips

Observations of the large-scale velocity field in galaxy surveys have revealed that the vorticity of matter flows — the curl component of the peculiar velocity field — shows unexpected coherence and sign-flipping patterns across spatial scales of tens to hundreds of megaparsecs. In linear perturbation theory, vorticity modes decay as the universe expands and should be negligible by the present epoch in ΛCDM. The detection of non-negligible vorticity in reconstructed peculiar velocity fields, and particularly the branching patterns in which vorticity changes sign coherently along filaments and at void-wall interfaces, is not predicted by standard ΛCDM structure formation and has been tentatively attributed to nonlinear mode-coupling or systematic errors in the velocity reconstruction.

Successive Collision Theory predicts a non-negligible residual vorticity field as a direct consequence of angular momentum inheritance. The initial pocket collision deposited angular momentum J into the debris field with a specific spatial distribution set by the collision geometry. As large-scale structure assembled from this debris, the angular momentum was redistributed through gravitational interactions but remained approximately conserved in total by Noether's theorem. The present-day vorticity field is therefore a fossil record of this primordial angular momentum distribution, not a decaying relic of linear perturbation modes but a physically sourced, conserved quantity that traces the spatial gradient of the inherited angular momentum field. The sign-flipping pattern of vorticity along filaments reflects the transition between regions that inherited angular momentum with opposite projected components along the line of sight — a geometric consequence of the collision's impact parameter and the resulting helical structure of the angular momentum field.

The branching character of the vorticity sign transitions in SCT arises at the intersection of angular momentum strata in the debris field: where two regions with opposite angular momentum orientations meet along a filament, the vorticity necessarily passes through zero and changes sign, producing the observed branching pattern. This is physically analogous to the disclination lines observed in liquid crystal systems where orientation fields rotate by 180 degrees. SCT predicts that the branching vorticity pattern should be spatially correlated with the large-scale filament network and with the spin alignment of galaxies within those filaments — both reflecting the same underlying angular momentum field — providing a cross-correlation test using combined peculiar velocity surveys and galaxy morphology catalogs.