Special relativity treats time as a coordinate. General relativity treats it as a component of the dynamic spacetime manifold. Thermodynamics gives it a direction. None of these accounts explain what time is at the physical level - what physical process constitutes the passage of time at a given location.
BFUT Paper 22 answers it. Time is the accumulated evolution of states in the Spaticle substrate at a given location.
The Propagation Budget
The Spaticle substrate has a finite capacity for reorganisation per unit time - the maximum rate at which substrate states can change is c. When a system moves at velocity v through the substrate, a fraction v²/c² of the total propagation budget is committed to spatial traversal. The remaining fraction is available for internal state evolution:
η is the Lorentz factor - the fraction of the propagation budget available for internal evolution. A system moving at v = 0.6c has η = 0.8: 80% of its budget goes to internal evolution, 20% to spatial motion. Its clock runs at 80% of rest rate. Time dilation is not mysterious - it is propagation budget accounting.
Why Clocks Slow Near Mass
In a gravitational field, the substrate is deformed by the presence of mass. The deformation reduces the local effective propagation capacity. A clock in a gravitational field has less propagation capacity available for internal evolution - fewer state evolution cycles per external reference interval - so it runs slower. Gravitational time dilation is the reduction of local propagation capacity by substrate deformation.
Special and General Relativity Unified
Both SR and GR time dilation are the same physical mechanism in different contexts: the propagation budget available for internal substrate evolution is reduced - by spatial motion in SR, by gravitational substrate deformation in GR. The mathematical forms are the same because the mechanism is the same. One substrate, one propagation capacity, two observable consequences.
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