Mars First: A Geometric Derivation of Martian Biological Priority, the Inversion of the Panspermia Prior Probability, and the Testable Prediction That the Oldest Known Biosphere in the Solar System Is Fossilised on Mars

A geometric derivation establishing that Mars was habitable before Earth was stably habitable, that the Cheyava Falls biosignature features (Hurowitz et al., Nature 645, 2025) are consistent with a mature LUCA- biosphere in terminal collapse at or before the age the earliest confirmed Earth biosignatures (~3.5-3.8 Ga), and that this inverts the prior probability of panspermia from exotic hypothesis to default hypothesis requiring elimination. The argument proceeds from four independent lines: planetary cooling physics, Cheyava Falls community maturity indicators, the time-constraint on biological cascade completion, and the confirmed reality of Mars-to-Earth meteorite transfer. Three testable predictions are pre-registered prior to Mars sample return and prior to any genomic analysis of Martian material: (1) Martian biological activity dates to ≥3.8 Ga; (2) genomic analysis will reveal either common origin or independent biochemical architecture with no third option; (3) the vivianite horizon at Cheyava Falls marks the biological cessation boundary of the Martian surface biosphere. Derivation originated in cancer attractor geometry with no prior astrobiology knowledge.