Andrew Trapp wrote:
> Ah, but we CAN create regions of space-time with less density than
> "normal" vacuum. Ever hear of the Casimir effect?
Yes, this is the one exception which I did not mention, mainly because it is a construct, although it is thought that gravity may actually be a manifestation of the casimir effect in the natural world. What good is the Casimir Effect? Well, if you could somehow make a tunnel from point A to point B through space, then you would have a free, cheap, and easy way to travel to the stars, as the tunnel walls would protect the space you travel through, allowing FTL travel, while the EM energy behind your ship would propell you through the tunnel to the halfway point, and the pressure coming in from the other end would slow you down. Of course you could help it along by stationing a high power laser at each end.
This is a hell of a cosmic tube, and I have no idea what sort of pressure densities there will be at the midpoint...though a laser's output should balance it. A bit like a huge pneumatic tube system.... now this is a job for buckytubes....
"Live free or die, death is not the worst of evils"