Even if the laws of physics permitted backward time travel, engineering a time machine would confront staggering technological hurdles. Creating a traversable wormhole, for instance, would require stabilizing it with exotic matter that possesses negative energy density—something only observed in minuscule quantum effects like the Casimir effect, far from the macroscopic amounts needed. Accelerating a spacecraft to relativistic speeds for significant future travel demands energy comparable to the total output of humanity for years. Moreover, maintaining coherence and protecting occupants from extreme tidal forces and radiation near such structures remains unsolved. Consequently, while the principles are known, practical realization is likely beyond any foreseeable capability.