Chapter 7: Boundary Data: CMB and Cν

The cosmic microwave background (CMB) and the cosmic neutrino background (CνB) are the two oldest electromagnetic and non-electromagnetic signals accessible to observation. Orthodox cosmology treats them as datasets: the CMB power spectrum constrains six cosmological parameters, and the CνB (as yet undetected directly) constrains neutrino properties and the thermal history of the early universe.

This chapter interprets both backgrounds as constraint surfaces of the boundary holonomy algebra H_∂[ω] at specific orbit depths on τ¹. The CMB encodes the state of H_∂[ω] at the recombination orbit depth n_rec—the orbit at which the baryon–photon fluid releases its photons as free-streaming null intertwiners (§). The CνB encodes an earlier state at the neutrino-decoupling orbit depth n_ν < n_rec—a time-like echo of the deeper past (§). Both surfaces constrain the subsequent physics of Parts II through VIII (§). The chapter closes with a preview of the power spectrum predictions that will be developed in the falsification pack of Part VI (§).