[NicknamedBob]

"There would be no acceleration; the ship does not move in the normal space. The acceleration (such as stretching of the space) occurs within an infinitely thin border of the bubble, but that border is far enough from the outer walls of the spacecraft. "

Yeah but, with all this stretching of space going on, what happens when you try to come back the other way?

Does space start getting compressed again? What about "stretch" marks?

You could run into a wrinkle in time.

I may need to go out and sit on a rock in my back yard to ponder this.

[GeronL]

lol

good questions

Hopefully it won’t permanently damage the fabric of space-time.

(I actually wrote a story once where a technology did just that, tear holes in the fabric of space... I lost it a while back though... drat)

[Riley]

There’s a thought- I need a ponderin’ rock for my backyard. All I have is a pile of old lumber.

[Dr. Bogus Pachysandra]

“What about “stretch” marks?”

Spaghettification? The “Noodle Effect?”

http://en.wikipedia.org/wiki/Spaghettification

Would make a good “Word for the day!”

[Greysard]

I may need to go out and sit on a rock in my back yard to ponder this.

A backyard is a good place to do the following experiment.

Take an infinitely stretchable rubber thread and tie it to two fence posts. This is your space. Then grip the thread near one post and drag that point all the way to the other post. That's how the FTL spaceship would travel within a very small time. Note that if there is an ant sitting on the thread where you gripped it, the ant is not in motion relative to the thread. If you ask the ant, he will tell you that suddenly the space in front of him compacted, the space behind him stretched, and he was propelled - without moving - all the way along the thread.

Another experiment - that requires an oceanfront property - is the wave. Water rises, forms a wave and then falls. The wave itself is moving, but the particles of water do not. If you ride the wave you can move pretty fast, even though the water itself is not moving (other than vertically.)

Alcubierre drive compresses the space in front of the bubble and stretches it back after the bubble passes. In essence, the bubble is riding the wave:

As things are, there are a few small difficulties remaining, such as the need to have considerable mass of exotic matter. Some calculations put it to be larger than the mass of this Universe; but other calculations say that a few milligrams will suffice. To make things worse, nobody on this planet have ever seen exotic matter; nor anyone knows how to make one.