The Interior Observer Cosmological Framework: Paper 1 - A Black Hole Cosmology with the CMB as Event Horizon Radiation

Foundational paper of the Interior Observer (IO) cosmological framework. Beginning from two premises - (1) the observable universe exists inside a Schwarzschild black hole, and (2) physics inside the horizon equals physics outside - this paper presents the framework's origin story (formation event, horizon containment, hot mostly-radiation boundary state) and enumerates the ten structural consequences that fall out before any derivation work begins. The paper then derives three results that originate in Paper 1 and remain load-bearing across the 35-paper series: the CMB temperature formula via 1+1D CFT mode counting on the horizon (T_IO = 2.6635 K, 2.3% from FIRAS), the Interior Observer Spectral Theorem proving greybody factor Γ = 1 exactly, and the dark energy density ρ_Λ = 5.82 × 10⁻²⁷ kg/m³ from Einstein-Cartan-Holst torsion (2.4% from observed, zero fitted parameters). §6 summarizes the framework's closure through Paper 32 and the consequence phase across Papers 33-35. v4.0 is a structural rebuild of Paper 1 as an origin story. "If the theory is correct, the math will just work." https://dfife.github.io/index.html v4.0 (May 2026): Structural rebuild of Paper 1 as an origin story. The paper opens with the formation event - the moment a containing black hole closes around a region of spacetime - and unfolds the framework from there. §2 enumerates the ten structural consequences that fall out of the two premises before any derivation work begins, giving the reader the framework as a single object rather than as a sequence of discoveries. New §2.6 derives the hot mostly-radiation first-cycle boundary state from horizon containment of the formation event's outward pressure, replacing the v3.5 treatment of the initial singularity as an inherited Oppenheimer-Snyder endpoint. The temperature formula, the spectral theorem, and the Einstein-Cartan-Holst dark energy derivation are preserved from v3.5 with voiced openings. The DESI confrontation, MOND identification, and CMB power spectrum sections from v3.5 are superseded by published Paper 17 v1.5, Paper 29, Paper 31, Paper 32 v2.0, Paper 34 v2.0, and Paper 35 v2.0 content and are removed from Paper 1; pointers are retained in the consequence chain. New §6 distinguishes the framework's closure (Papers 2-32) from the consequence phase (Papers 33-35). New §7 falsifiability section names the experiments that would force the framework into rework. Notation moved to Appendix A. Numerical constants updated to the current published values. Dash discipline: hyphens only. Numerical correction in §5: at the v4.0-stated γ_BI = 0.2375, the dark energy chain gives ρ_Λ,torsion = 2.52 × 10⁻²⁷ kg/m³ and ρ_Λ,eff = 5.82 × 10⁻²⁷ kg/m³ (2.4% from observed), correcting the v3.x legacy values 2.62 × 10⁻²⁷ / 6.05 × 10⁻²⁷ (1.5%) which had been carried forward from the v3.x γ_BI = 0.1274 (Meissner 2004) convention. The geometric mechanism and (l_P/r_s)² hierarchy argument are unchanged; only the input γ_BI value shifts the numerical result. Paper 32 v2.0 SHA reference updated to current public-repo manifest (2e1ff99e). Reproducibility bundle paper1-v4.0 published (SHA256 prefix 812ed680, validator 24/24 PASS, release tag paper1-v4.0). See https://github.com/dfife/io-framework-public/tree/main for claim naming convention. v3.5 (March 2026): Cycloid parameterization correction. The OS cycloid has been corrected from a(η) = (r_s/2)(1+cos η) (contracting phase) to a(η) = (r_s/2)(1−cos η) (expanding phase), consistent with observed cosmological expansion. η=0 is the Big Bang (a=0); η=π is maximum expansion (a=r_s). The current-epoch conformal time shifts from η ≈ 0.196 to η ≈ 1.371 (temporal) and from η_s = 1.249 to η_s = 1.893 (spatial). The geometric ratio x = r_s/R_U = 1.519 and all derived observables (T_IO, ρ_Λ, a₀, H₀) are invariant. §6.4 ρ_Λ evolution direction corrected for expanding convention. Title page reformatted to series standard. See Paper 21 v1.1 for the full audit. v3.4 correction note: v3.2 reported χ² = 15.1 at zero free parameters. Paper 3 identified two errors: (1) the Ω_k normalization used a = r_s instead of the correct a = R_U, shifting Ω_k from −0.057 to −0.130; (2) the DESI comparison used D_V/r_d at all redshifts, but data at z ≥ 0.510 reports D_M/r_d. Both errors independently verified by Gemini. Core predictions (T_CMB, ρ_Λ, a₀, γ derivation) are completely unaffected. v3.4 additionally corrected Paper 1 Table 2 values (H₀ 58.5→58.4, Ω_Λ 0.919→0.933) and standardized decimal precision across all constants. See Paper 3 for full correction analysis. Three changes: T_CMB 2.66→2.663, a₀ 1.35→1.345, and the correction note updated from v3.3 to v3.4 with the Table 2 and precision fixes documented. Everything else unchanged and consistent with Paper 3 v1.3. Paper 4 status: All four core predictions from Paper 1 are verified and extended in Paper 4. The ρ_Λ derivation is confirmed via two independent routes, recovering the Barbero-Immirzi parameter γ_BI to 2.9% of the LQG value (25/25 SymPy checks). The MOND scale a₀ = c²/r_s is confirmed as a zero-parameter prediction; the interpolation function μ(a/a₀) is identified as requiring quantum gravity completion. Paper 1 §6.4's claim that w = −1 is confirmed by CAMB (w = −1/3 ruled out at χ² = 716). Structure formation is proven viable: the OS dust clusters gravitationally, identifying dark matter as the interior geometry itself. The CMB first acoustic peak is predicted at ℓ₁ ≈ 180 (Planck: 220), an 18% tension driven by Ω_m h² = 0.067, which is the framework's most significant open problem. Paper 1 Open Questions #1–5 are all addressed in Paper 4. Companion to Paper 2 (DOI: 10.5281/zenodo.18868612), Paper 3 (DOI: 10.5281/zenodo.18876346), Paper 4 (DOI: 10.5281/zenodo.18883069), Paper 5 (DOI: 10.5281/zenodo.18889865), and Paper 6 (DOI: 10.5281/zenodo.18891475).