The Eridanus supervoid is an enormous underdensity in the galaxy distribution spanning 250 to 300 Mly, located in the constellation Eridanus (Granett 2010; Keenan 2013). Such extreme underdensities are statistically improbable in a universe starting from Gaussian random density fluctuations as inflation predicts. The supervoid's existence and properties strain the assumptions of homogeneity and structure-growth rates central to ΛCDM.
The standard model assumes Gaussian initial conditions plus standard hierarchical structure growth. Voids of Eridanus's scale and depth occur as statistical tails (rare outliers) under those assumptions. Finding multiple comparable supervoids in our observable patch (KBC, Eridanus, Local Supervoid, etc.) makes the rare-outlier interpretation strained.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, supervoids are inevitable inter-filament regions of the cascade-deposited cosmic web, not rare statistical fluctuations (P22, P34). The cascade impact-parameter distribution P(b) ∝ b combined with head-on cascade collisions producing filaments (P33) produces a foamy cosmic-web morphology with filament-bounded voids as common geometric elements.
Each supervoid contributes a dynamical-Λ_eff enhancement (P17, P19) that adds about 1 to 2 km/s/Mpc to local Hubble inferences. Eridanus, KBC, the Local Supervoid, and the catalog of other supervoids in our local cosmological neighborhood (P26, Local Big Bang context) make multi-supervoid environments common. Combined supervoid demographics plus temporal Λ_eff evolution (P14, P15, P16, P18) explains the Hubble tension as the natural integrated signature of being embedded in an underdensity-rich cosmic-web region.
The Eridanus supervoid's location aligns approximately with the CMB Cold Spot direction (recid 23 cross-link via recid 102), providing geometric cross-check between the void distribution and the cascade-thermalization heterogeneity that produced the Cold Spot. The same M4 framework that produces the gigaparsec ring-and-arc structures (recid 85), the KBC supervoid abundance (recid 86), and the cosmic-web morphology produces the Eridanus supervoid as a predicted geometric feature. There is no need to invoke non-Gaussian initial conditions or modified structure growth.
If precision DESI + Euclid + SKA void-abundance census finds the supervoid size function consistent with ΛCDM Gaussian-tail predictions at the 1% level (no excess of large supervoids beyond standard expectations), the M4 cascade-stream void origin is refuted. The signature SCT prediction is roughly 5 times more large supervoids than ΛCDM Gaussian-tail simulations expect.