99% of the people in this thread have absolutely no idea about half the physics they're talking about. I'm sure as forget I don't, but I definitely understand more than some of the people here.
From what I think I understand:
You cant really compare this concept to changing air pressure, although it is similar. Think of it in steps:
It makes the space in front of the ship smaller, so the distance to the target destination from the ship is smaller.
It moves forward through the space, probably just using orbital velocity, or some generic thrusters.
Then it expands the space behind it to make it back to normal.
It does all this constantly, so that space isn't forgeted up around it (it would break some rule of physics somewhere otherwise).
About the whole 'how to power this' thing which some guy raised; As far as I can tell, the amount of energy required isn't actually that much. Sure, its more than your computer uses, but from that link, he said something like it will cost around the same energy as [another spaceship] has (in terms of mass). If by that it is only considering the gravitational potential energy from the ship, then that is a tiny amount. Like, probably less than a lightbulb. Of course, there will be other parts of the device that require power, so it wont be cheap to run, but sure, whatever, its nasa, im sure they have a renewable power generator lying around somewhere.
About colliding with space-junk and particles and stuff; I'm not too sure about it. Yes, there is definitely stuff in space, particles of stuff, asteroids, etc.. I guess what will happen is:
Only objects that are in the way of the space infront of the ship thats being shrunk could cause a problem. I think it would actually turn smaller (from the ships point of reference), until it gets into the space around the ship that isn't shrunk, and then you would just have a giant asteroid in your face. You wouldn't be moving any faster relative to it than you would be if you got there normally. What would be more interesting is if an object goes past the ship, but still in the area of effect. If you looked behind you, you would see fricken giant ass asteroids like right behind you, and then they would shrink to regular size.
Ill probably think of more crap to say after I've posted this..
Poll