Acoustic Peak Positions

The positions of the acoustic peaks in the CMB power spectrum encode the sound horizon — the distance a pressure wave can travel in the photon-baryon plasma from the moment of thermalization to the moment of decoupling. In ΛCDM, the precise angular positions of these peaks constrain the baryon density, matter density, and angular diameter distance to the last scattering surface; any mismatch between independently inferred distance scales (for instance, those from the BAO ruler versus Planck CMB fitting) constitutes a tension. In SCT, the thermalization event is the superluminal collision itself. The collision deposits energy simultaneously across the overlap volume, creating a plasma whose initial conditions are set by the collision kinematics and the density of pre-existing matter in the two pockets. Once thermalized, this plasma evolves according to standard fluid dynamics in curved spacetime, generating the same acoustic oscillations that ΛCDM describes. The sound horizon and hence the angular peak positions are therefore determined by the same six state parameters — the SCT origin changes where those parameter values come from, not the acoustic physics that follows.

The mild tensions in peak positions that have emerged between high-redshift CMB fitting and low-redshift BAO measurements are accommodated in SCT through the dynamical effective cosmological term Λ_eff. Because Λ_eff varies spatially — elevated in underdense voids like the KBC Supervoid we inhabit, suppressed in dense clusters — the locally inferred expansion history differs slightly from the globally averaged one. This spatial variation means that the angular diameter distance to the last scattering surface computed from a local expansion history will be shifted relative to the true global value, producing apparent shifts in peak angular positions that are not present in the underlying physics. SCT thus provides a causal mechanism for distance-scale discrepancies that ΛCDM must absorb through parameter freedom or unexplained systematics.