The CMB Cold Spot (a roughly −70 to −150 microkelvin temperature deficit at the Eridanus location) sits along a line of sight that passes through the Eridanus Supervoid. Standard ISW + Rees-Sciama physics in ΛCDM accounts for only 10 to 20% of the Cold Spot depth from the Eridanus underdensity (Finelli 2014; Kovács & García-Bellido 2016; Mackenzie 2017). Lensing constraints rule out a single sufficiently deep void to close the budget within standard ISW physics.
The standard model assumes void-CMB cold deficits come from standard ISW plus Rees-Sciama with constant Λ. The Eridanus supervoid is too shallow to produce the full Cold Spot under these assumptions. Closing the budget requires either invoking an unconfirmed deeper second void, modifying ISW physics, or attributing the Cold Spot to a primordial cascade-thermalization heterogeneity (recid 23).
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, voids carry enhanced Λ_eff sourced by their underdensity (P14, P15, P16, P17). The enhanced Λ_eff redshifts CMB photons traversing the void line of sight more than standard ISW calculations expect, providing the additional cold contribution that closes the budget. KBC calibration (P19) sets the amplitude: a typical 20% underdensity gives 10 to 20% enhanced Λ_eff, sufficient to produce the observed roughly 70 microkelvin Cold Spot deficit at Eridanus.
The mechanism is the same as the broader stacking-voids cold bias (recid 98). Mesh dissipation manifests as redshift, not heating; void interiors integrate this redshift along the photon's path, giving a deeper cold spot than ΛCDM ISW alone predicts. Gravitational superposition (P50, P52) adds a smaller Φ_mesh contribution that modifies the apparent matter underdensity through the coherent contribution from the parent-frame mesh.
The Eridanus Supervoid + Cold Spot link is therefore the predicted cascade-geometry signature: the supervoid is one of the cascade-stream voids in our local cosmic-web region (recid 89), and its enhanced Λ_eff produces the line-of-sight cold deficit that aligns with the Cold Spot location. The same M5 framework that resolves the broader CMB Cold Spot (recid 23, where r23 attributes the residual to cascade-thermalization heterogeneity from M2) and the void cold bias produces the supervoid–Cold Spot link as a unified signal. There is no need to invoke an unconfirmed second deeper void.
If precision Simons Observatory + CMB-S4 cross-correlation of supervoid stacking with line-of-sight cold deficit finds the Eridanus contribution consistent with standard ISW alone at the 5 microkelvin level (no Λ_eff-enhanced redshift signal), the M5 mesh-dissipation cold-deficit explanation is refuted. The signature SCT prediction is the Λ_eff cold contribution scaling with void underdensity at the calibrated rate.