>On Mon, 16 Dec 1996 Hal Finney <hal@rain.org> Wrote:
>>today there are several ideas for FTL travel, including
>>wormholes (discussed at length on this list a few years ago)
>>and the Alcubierre "warp drive".
>It seem that all these ideas need to invoke new physics, at least a little,
>at some point or another. For example, Kip Thorne's wormholes need
>"Exotic Material", that is, material that has a negative energy density
>from light's frame of reference. Nothing like Exotic Material has ever been
>observed and there is no theoretical reason to think it exists, but I admit
>there is no theoretical reason to think it doesn't either.
FTL travel allows you to set up very nasty paradoxes. Just that something
would allow FTL is a good theoretical reason to doubt its existence.