Filaments rotate. MeerKAT caught a 1.7 Mpc filament in coherent bulk rotation at about 110 km/s (Tudorache 2025), simulations find vorticity along filament spines with aligned halo spins (Codis 2015; Wang 2021), and tidal torque theory, the model's only spin source, cannot produce ordered rotation at that amplitude or coherence on those scales.
The model's initial conditions are irrotational and gravity conserves circulation, so all spin must be torqued up locally during collapse. That mechanism fades beyond tens of megaparsecs and never produces bulk rotation of an extended structure, leaving megaparsec-scale filament angular momentum with no source at all.
SCT never needs to generate the angular momentum, because it was deposited at the start. The collision that created each structure carried J = μ(b × v_rel) (P31), and filaments, as direct structural relics of the cascade's head-on events (P33), inherit their share of that vector as bulk rotation rather than acquiring it later by torque. A filament rotating as a body is exactly what a deposited, conserved angular momentum looks like; it is only mysterious if the rotation had to be assembled from curl-free initial conditions.
The inheritance principle (P32) makes this quantitative and falsifiable across the whole hierarchy: the same J ∝ M^(5/3) scaling observed across seven decades of scale should hold for filament populations, with specific angular momentum running as M^(2/3), and the spin-alignment coherences that exceed tidal torque theory by factors of 10 to 20 are the registered M3 signature, not an embarrassment. The filament bulk-J derivation is in Paper 5, From Chaos To Corotating Hierarchies, Section 5.9, with the 110 km/s detection sitting in the canonical ledger as a confirmed prediction. The same deposited vector carries cluster rotation at 360 to 693 km/s across the Tang mass range, satellite-plane co-rotation, and the quasar polarization coherence; filament vorticity is one more instrument reading the one vector.
Keystone economy: P31 deposits, P32 conserves, P33 builds the filament around it. Tidal torque theory is not wrong; it was simply never the source.
MeerKAT and SKA filament-rotation surveys carry the kill: if rotation amplitudes across a population of well-resolved filaments are consistent with tidal-torque and simulation expectations, with no bulk-rotation excess and no specific-angular-momentum scaling near M^(2/3), the deposited-J reading is refuted. SCT also requires the rotation amplitude to correlate with the mass ratio of the endpoint clusters, a registered population-level test no torquing mechanism reproduces.