 You'd have to have a lot of energy to collapse the space in front of you and expand the space behind you. Right. You're going to need mass to do that because that's the only way you can bend space, okay? And the mass that you're going to need is going to be roughly the size of Jupiter. And you're going to have to have some sort of energy source that can accelerate a mass the size of Jupiter to close to the speed of light.