Towards a 3D+2T Spacetime Model for Intergalactic Navigation

This paper proposes a 3D+2T (three spatial dimensions plus two temporal coordinates) framework for addressing the temporal paradoxes inherent in intergalactic travel and observation. The central thesis is that the two temporal coordinates (local time t₁ and cosmological time t₂) are not physically independent but represent different gauge choices of a single temporal degree of freedom—analogous to how the International Date Line creates coordinate discontinuities without physical time jumps. Key contributions include: (1) explicit formulation of temporal gauge equivalence, (2) a concrete 5D metric ansatz with gauge constraints ensuring reduction to 4D physics, (3) interpretation of wormholes as gauge transformation interfaces, (4) a phenomenological resolution of the Hubble tension via gauge-dependent Hubble parameters (requiring α/β ≈ 1.17), and (5) derivation of the 5D Einstein equation components in the Appendix. The framework draws connections to Itzhak Bars' Two-Time Physics and the Field-Fluctuation Universe (FFU) model, offering testable predictions for intermediate-redshift observations and gravitational wave signatures.