Absolute Now from a Universal Cycle Count: An Operational Foundation for Time and Simultaneity

This paper redefines time as a countable cycle count N = t / τ₀, where τ₀ is the period of a universal reference process (e.g., cesium-133). Absolute simultaneity is defined operationally: two events are simultaneous iff they share the same N. A preferred frame – the CMB rest frame – provides the reference for a universal clock. Transformation laws for moving observers are obtained from time dilation, two-way light speed isotropy, and the CMB dipole, with the spatial transformation chosen in the Selleri gauge to align with absolute simultaneity as defined by the cycle count. The framework does not claim to refute special relativity. Instead, it adopts a stance of naturalized conventionalism: the choice of the CMB frame and isotropic one-way light speed is a convention, but one that is empirically and cosmologically distinguished. Absolute simultaneity is presented not as a metaphysical fact but as a naturalized convention – the most operationally meaningful among empirically equivalent alternatives. This restores a robust, operationally defined notion of "now" without contradicting Minkowski spacetime. Experimental tests (direction-dependent clock drift, modified Doppler shift, GPS, muon lifetime) are proposed to bound deviations from Lorentz invariance via a generalised factor f(v) = 1/γ(v) + ε·g(v). The paper is part of the Ja Model research program, replacing time with motion cycles across all of physics.