P10: The Sunyaev-Zel'dovich Effect as Local Substrate Interaction: A Big Flare-Up Theory Reinterpretation

The Sunyaev-Zel’dovich (SZ) Effect - the spectral distortion of the Cosmic Microwave Background (CMB) radiation caused by inverse Compton scattering off hot electrons in galaxy clusters - is widely cited as one of the strongest proofs that the CMB is a distant background relic of the Big Bang. Within Lambda-CDM, the SZ effect is interpreted as light from a 380, 000-year-old recombination surface being filtered and energy-boosted as it passes through foreground galaxy clusters. The redshift-independence of the SZ surface brightness is treated as a consequence of the CMB photon energy density scaling as (1+z) ⁴ to exactly cancel the standard cosmological dimming. This paper re-examines every aspect of the SZ effect from within the Big Flare-Up Theory framework, which holds that the CMB is not a relic but a present-moment thermal equilibrium field maintained by the Spaticle substrate of the living universe. Under BFUT, the SZ effect is not a light-from-the-past phenomenon. It is a direct local thermal interaction between the hot intracluster plasma and the ambient Spaticle field. This reinterpretation accounts for all observed features of the SZ effect - including the thermal distortion, the kinematic component, the redshift-independence, and the pressure-proportional signal strength - without requiring an expanding universe, a surface of last scattering, or photons that have travelled for 13. 8 billion years. The paper also identifies two observational predictions of the BFUT reinterpretation that differ from Lambda-CDM: the relationship between SZ signal strength and local Spaticle field density, and the expected statistical behavior of the kinematic SZ component in bulk-flow-dominated regions. This paper is part of the Big Flare-Up Theory (BFUT) companion paper series. The BFUT proposes a living, infinite, non-expanding universe in which what we observe as cosmological redshift is the product of gravitational kinematic sorting rather than metric expansion of space. The framework has been developed and published across a main paper and companion papers addressing the Hubble relationship, the cosmological constant, the lithium problem, apparent cosmic acceleration, spatial infinitude, black holes, CMB temperature, CMB acoustic peaks, the pre-flare-up state of the universe, large-scale orbital hierarchy, and the physical nature of the Spaticle substrate of spacetime. The present paper addresses the Sunyaev-Zel’dovich (SZ) Effect - one of the major observational pillars of Lambda-CDM - and demonstrates that it is fully consistent with, and in several respects more naturally explained by, the BFUT living-universe framework. The reader is directed to the main BFUT paper (DOI: 10. 5281/zenodo. 19149785) for the foundational arguments and simulations underlying the framework. The core argument of each referenced paper is stated directly where relevant so this paper stands on its own merits.