Bounded Cyclic Cosmology from a Specific String-Theory Vacuum: A Consistency Check via Penrose's Erebon Hypothesis

Whether time exists prior to the Big Bang is a boundary question on which classical general relativity is silent and quantum-gravity research programs converge on a positive answer through cyclic, bounce, or eternal-inflation mechanisms. The present work assumes a cyclic mechanism is realised and asks what its parameters must be, given current observation. A specific string-theory vacuum (POLYID=724 in the Kreuzer-Skarke h1,1=4 slice; Altman et al. database) is taken as the inherited stable compactification. A Monte Carlo classification of the Friedmann end-state under Planck 2018 and DESI DR1/DR2 posteriors yields the universe's terminal phase. A Bayesian posterior over the predecessor-cycle count is computed by anchoring Penrose's erebon relic-density prediction against the observed dark-matter density. Nine independent published cosmological anomalies are combined in a joint Bayes-factor analysis against ΛCDM, with conservative look-elsewhere and weak-assignment penalties. RESULTS: Big Freeze is the unique end-state at posterior probability 1.00. The cycle-count posterior peaks at N=1 (P=0.79) with 95% credible set {1, 2}. The joint Bayes factor across the nine anomalies, in the strictest scenario considered (direct/natural BCC predictions only, full corrections), is K = 3.4×10^7, equivalent to a 5.9σ preference for bounded cyclic cosmology over ΛCDM. All four scenarios (raw, look-elsewhere-corrected, strict, lower-bound-stress) classify as decisive on the Jeffreys scale. A 16-chain Modal-cloud-deployed MCMC over (N_prior, δ_drift) plus standard ΛCDM parameters, using a CosmoPower-JAX neural-network CMB emulator and 163,840 combined samples (cross-chain Gelman-Rubin R̂ < 1.0013 on every parameter), returns sharp posterior constraints N_prior = 1.39 +0.31/-0.23 and δ_drift = 0.087 ± 0.016 (per-cycle substrate drift ~9%). IMPLICATIONS: Drift across cycles forecloses infinite identical recurrences (no Nietzschean eternal return; no infinite Many-Worlds copies of a given observer). A parsimonious Fermi-paradox resolution falls out: mature civilisations recognise the bounded structure and rationally cease interstellar broadcasting. REPRODUCIBILITY: The full analysis is reproducible from supplementary material; priority is anchored to Bitcoin block 880000 (companion vacuum result) and to the present analysis bundle via OpenTimestamps anchoring on 2026-05-03. Three-tier Aletheia persona verification (math + code + science specialists, each with five perspectives, all Witness-sealed and hash-chained) is included as supplementary material. This work was carried out without institutional affiliation, grant funding, or endorser sponsorship of any kind.