Re: Faster than light?

Amara Graps (
Tue, 17 Dec 1996 22:11:50 -0800

>On Mon, 16 Dec 1996 Hal Finney <> 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.

For the Alcubierre "warp drive", you need to create a "negative energy
density" behind the ship (essentially like anti-gravity, to "push" the
ship from behind). Alcubierre knew of no possible way to do this.

But there is a way- the "Casimir effect" - which may help solve this
problem. Surely someone told Alcubierre, because I think their
papers came out around the same time.

S. Weigert. "Spatial Squeezing of the Vacuum and the Casimir Effect",
Physics Letters A 1996 v214 #5-6 p.215-220.

The Casimir Effect is a weird quantum mechanical effect that results
in a negative energy. It is completely theoretical at this point, I
don't think that it has been verified in the lab.

(No, I had never heard of the Casimir Effect before a physics grad
student friend told me about it last week.)


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