Spacetime Travel

The big daddy of all travel concepts: moving through time as well as space in a controlled manner, typically by manipulating the geometry of spacetime itself via General Relativity. This isn't just going fast (relativistic travel), which only goes forward in time. This is about creating closed timelike curves—wormholes, warp drives, cosmic strings—to theoretically hop to the past or distant future without waiting. It's engineering the universe's roadmap to include shortcuts and loops.

Example: The Alcubierre "warp drive" concept is spacetime travel. It doesn't move the ship through space faster than light; instead, it contracts spacetime in front of the ship and expands it behind, effectively surfing on a wave of distorted geometry. The ship sits in a "warp bubble" not subject to relativistic effects. You arrive at your destination quickly without any time dilation mess. Another example is using a traversable wormhole: one mouth is accelerated to near light-speed and brought back, creating a time machine where entering one end exits the other in the past.

by Abzugal January 24, 2026

Noetherian Travel

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