Local Void Underdensity

The KBC supervoid — a roughly spherical underdensity of radius ~300 megaparsecs centered on the Milky Way — represents a matter deficit of approximately 20% below the cosmic mean. ΛCDM struggles to produce voids of this scale and depth from its Gaussian initial perturbation spectrum without invoking extreme statistical fluctuations. In Successive Collision Theory, voids of this character are natural consequences of collision geometry. When two spacetime pockets collide at a grazing angle, the swept intersection region concentrates matter into shells, filaments, and nodes; the interior of each pocket — the region least affected by the collision front — is evacuated as matter drains toward the collision-compacted shell walls. The KBC supervoid marks the interior of one such pocket, and we reside within it.

This location has direct, quantitative consequences for local cosmological measurements. SCT's dynamical effective cosmological term scales inversely with the local gravitational binding strength: in an underdense region where the tensor mesh of overlapping gravitational wells is approximately 20% weaker than the cosmic mean, the effective expansion rate is locally enhanced. This produces a locally measured Hubble constant roughly 2–3 km/s/Mpc above the global Planck value — precisely the magnitude of the Hubble tension. The Local Void underdensity is therefore not merely a structural curiosity but the direct physical environment that generates the Hubble tension's spatial component; both phenomena are unified explanations flowing from the same collision-pocket geometry rather than requiring separate fine-tuned solutions.