For as long as humans have looked upward, the stars have represented the horizon of the possible — close enough to name, too far to reach. Now, a generation of theoretical physicists is working within the strict grammar of Einstein's equations to ask whether spacetime itself might be the vehicle: through warp bubbles that fold the cosmos, tunnels that connect distant regions, or the gravitational slingshot of a spinning black hole. None of these ideas has crossed from mathematics into matter, yet each one keeps alive the oldest human question — not merely whether we can go, but whether the uni