For example, if one wanted to travel to Deneb 2,600 light years away and arrive less than 2,600 years in the future according to external clocks, it would be required that someone had already begun work on warping the space from Earth to Deneb at least 2,600 years ago, in which case "A spaceship appropriately located with respect to the bubble trajectory could then choose to enter the bubble, rather like a passenger catching a passing trolley car, and thus make the superluminal journey."
Alcubierre metric (which has been used as a speculative toy model of effectively superluminal space travel, as in the warp drive from Star Trek).
Van Flandern supported Le Sage's discredited theory of gravitation, according to which gravity is the result of a flux of invisible "ultra-mundane corpuscles" impinging on all objects from all directions at superluminal speeds.