Void Demographics

The observed distribution of cosmic voids — their number counts as a function of size, their depth profiles, and their abundance at different redshifts — shows systematic departures from ΛCDM's predictions. There are too many large, deep voids relative to the standard model's expectations, and the distribution of void radii has a different shape than gravitational evolution from inflationary seeds predicts. Successive Collision Theory provides a physically motivated explanation: voids are not solely the result of matter draining away from underdense initial regions through gravitational collapse. They are also produced by the collision geometry, which creates evacuated pocket interiors of a size set by the original spacetime pocket dimensions. This adds a second void population at large radii — the collision-pocket interiors — on top of the standard gravitationally evolved void population, naturally shifting the void size function toward larger, deeper voids.

The depth profile of SCT collision-pocket voids also differs from gravitationally sculpted voids. Gravitational voids develop density profiles that rise gradually from the center outward, with a relatively smooth boundary. Collision-pocket voids have sharper boundaries set by the swept compression shell, and their interior density is more uniformly depleted because the evacuation was driven by the collision front sweeping matter outward rather than by matter slowly draining under gravity. The SCT void demographic therefore predicts a bimodal void population when characterized by boundary sharpness: smooth-walled, moderate-depth gravitational voids at small radii, and sharp-walled, deep collision-pocket voids at large radii. This bimodal signature in void demographics provides a direct observational test of the SCT collision framework using void catalogs from wide-field surveys such as DESI and Euclid.