*Spacetime Motion as Phase Selection: Recasting the Spacetime Interval, Time Dilation, and Cosmic Memory in an SP3 Universe

In standard relativity, spacetime is treated as a unified geometric manifold in which motionis distributed between spatial and temporal components according to an invariant interval.Standing still corresponds to maximal progression through time, while motion at the speedof light corresponds to maximal spatial propagation with vanishing proper time. Thisinterpretation implicitly assumes that spacetime is unitary, memoryless, and exhausted bygeometry. In this paper, we revisit this framework under the Space-Phase-3 (SP3)hypothesis, in which spacetime is composed of multiple operational space-phases withdistinct propagation, relaxation, and coupling properties. We show that the spacetimeinterval becomes a constraint describing phase accessibility rather than a fundamentalidentity, that time dilation experiments probe phase selection rather than timesuppression, and that previously unexplained persistence phenomena—rings, black holeenergy storage, and gravitational memory—emerge naturally. SP3 reframes motion not as aredistribution between space and time, but as a dynamical interaction with structuredspace itself.