In one minute

S. V. Krasnikov asks whether a traveller who can partly control spacetime geometry could reach a distant object and return sooner than light would. The stakes are distance: about 200 parsecs to Polaris, 500 to Deneb and around 10 kiloparsecs to the galactic centre. Under reasonable assumptions in globally hyperbolic spacetimes, the outbound trip itself cannot be sped up. Yet an arbitrarily long round trip may take an arbitrarily short time as seen from Earth. The key difference lies in the return leg, since devices placed along the route in advance can reshape spacetime so the traveller comes back early.

Hyperfast Interstellar Travel in General Relativity