August 2026
By Kevin L. Brown
This paper proposes the Harmonic Cross-Domain Planetary Mega-Cycles Hypothesis, a falsifiable model for testing whether major multimillion-year patterns observed across Earth’s geological, climatic, geochemical, geomagnetic, and biological records are independent periodic phenomena or coupled expressions of a deeper planetary-scale temporal architecture.
Previous studies have reported recurring structure near approximately 26–36 million years in extinction, tectonic, volcanic, sea-level, climatic, oceanic, and other geological records. Additional periodic components have been reported near approximately 12–14 million years and 8–10 million years. Examples include a 27.5-million-year cycle identified in a compilation of 89 major geological events, an 8.9-million-year component within the same broad event record, approximately 12.9-million-year structure in continental flood-basalt ages, approximately 13-million-year periodicity reported across geomagnetic reversal frequency, climate proxies, and subduction rates, and shorter multimillion-year components detected in sea-level, anoxia, volcanism, and biodiversity records. These findings motivate a direct cross-domain test rather than treating each periodicity as an isolated observation.
The proposed hypothesis uses Triune Harmonic Dynamics as the theoretical framework. It predicts that a candidate fundamental mode near 27 million years should be accompanied by shorter modes near 13.5 million years and 9 million years, corresponding approximately to a 1:2:3 frequency relationship. The hypothesis does not claim that every Earth-system domain must express each mode with equal strength, nor that every cycle must produce the same geological or biological outcome. Instead, different planetary subsystems may express different components or phases of a coupled harmonic structure.
The primary scientific test is therefore not the existence of periodicity alone, but whether independently reconstructed Earth-system records exhibit statistically significant harmonic phase relationships and cross-domain synchronization beyond appropriate structure-preserving null models. Candidate domains include plate reorganization, subduction, volcanism, sea-level change, oceanic anoxia and geochemical disruption, long-term climate behavior, geomagnetic reversal activity, biodiversity turnover, and extinction. Impact cratering and astronomical or galactic cycles are discussed as possible auxiliary or pacing mechanisms, but no external or internal causal driver is assumed in advance.
The paper defines measurable observables, a cross-domain structural-pressure concept, phase-locking tests, model-comparison requirements, and explicit falsification conditions. The hypothesis is rejected if the proposed harmonic relationships fail to appear robustly, disappear under reasonable uncertainty treatment, remain confined to isolated datasets, or provide no explanatory or predictive advantage over conventional independent-cycle models.
If supported, the model would suggest that Earth’s deep-time history contains a measurable hierarchy of coordinated planetary rhythms linking geological, environmental, and biological change. The work is presented as a testable scientific hypothesis and as a framework for future quantitative, cross-domain analysis rather than as an established explanation of Earth-system evolution.
The paper also distinguishes preliminary consistency from confirmation. Existing published periodicities are treated as motivating evidence because they were known before this hypothesis was formulated. Decisive support requires direct testing of the predicted relationships using current geochronology, realistic age uncertainties, alternative estimators, and independent or minimally overlapping datasets. Competing explanations remain open, including mantle and core dynamics, plate-tectonic feedbacks, volcanic forcing, orbital modulation, galactic motion, impact processes, nonlinear coupling among Earth subsystems, or combinations of mechanisms operating at different temporal scales.