Many cosmic voids exhibit relatively steep density transitions at their boundaries, with galaxy counts and matter density rising quickly over a small radial range as one moves from void interior into surrounding filaments and walls (Colberg 2005; Hamaus 2014; Ceccarelli 2013). ΛCDM predicts smoother more gradual density profiles. Reproducing the sharp quasi-compensated edges seen in surveys requires fine-tuned galaxy bias, complex feedback, or special selection.
The standard model assumes voids form from gradual gravitational evacuation of underdense Gaussian-initial-condition regions, producing smooth radial density profiles. Cliff-like sharp edges have no natural source in the model except through fine-tuned bias or feedback prescriptions calibrated separately for each void.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, void boundaries correspond to cascade-stream filament edges with well-defined widths set by the cascade-collision geometry (P22, P33, P34). Filament thickness scales as W ∝ M_min^(1/3) from the smaller pocket's self-gravity, producing a sharp transition between the dense filament and the underdense void rather than a smooth gradient.
The multi-stage cascade (P36, P37, P38) deposits plasma in cascade-stream-defined boundaries with characteristic widths set at deposition rather than equilibrating over cosmic time through gravitational collapse. The KBC supervoid (P19) and the broader supervoid population (recid 95) inherit these sharp cascade-stream-defined boundaries from their parent cascade events. Predicted void edges are roughly a factor of 2 to 3 sharper than ΛCDM N-body predictions, with sharpness correlating with the parent cascade-stream geometry.
Mesh dissipation (P14, P15, P16) and dynamical Λ_eff (P17, P19) enhance the in-void underdensity, making the contrast between void interior and filament boundary even sharper than at deposition. The same M4 framework that produces the void demographics (recid 95), the KBC supervoid (recid 86), the Eridanus supervoid (recid 89), and the cosmic-web morphology produces the sharp-edge signature. There is no need for fine-tuned bias or feedback prescriptions.
If precision DESI + Euclid + SKA void-edge profiles find density transitions fully consistent with ΛCDM N-body smooth predictions at the 1% level (no factor-2 sharpness excess, no correlation with cascade-stream geometry), the M4 cascade-stream-edge explanation is refuted. The signature SCT prediction is sharper void edges with width set by the cascade-stream filament boundary scale W ∝ M_min^(1/3).