A theoretical propulsion concept that abuses the symmetry-conservation link for movement without apparent reaction. It seeks to engineer a scenario where the symmetry of your vehicle's local physical laws is carefully manipulated, and the resulting conserved quantity (usually momentum) is not expelled locally but is instead "handed off" to a distant field or another part of spacetime geometry. The goal is motion that looks like it violates Newton's third law (for every action, an equal reaction) by satisfying it non-locally via deep physics.
Example: The "Phase Sail." The ship's drive doesn't expel mass. Instead, it cyclically changes the internal gauge symmetry of its quantum vacuum core. Noether's Theorem says this changing symmetry must be accompanied by a conserved current (momentum). By coupling this process to the ship's hull and, crucially, to the background Higgs field of the universe, the momentum conservation is satisfied by imparting an infinitesimally small, opposite change in the field's configuration across the cosmos. The ship moves because the entire universe imperceptibly "pushes back" in a diffuse, non-local way. You're not pushing against anything nearby; you're leveraging the universe as your reaction mass. Noetherian Travel.
by Dumuabzu January 24, 2026
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