A wormhole question

[Ender]

Is it possible to make wormholes work in a universe where casualty still survives? I mean like handwaving that the tidal forces are such that anything sent through is randomized, making it impossible to send information at FTL speeds? I realize that things like quantum spin, charge, etc would also have to be wiped to prevent information from being transmitted, is something liek this physically possible, or just a load of writer crap?

And yes, there are uses for that kind of wormhole - it would be a very effective generator.

[metavac]

Is it possible to make wormholes work in a universe where casualty still survives? I mean like handwaving that the tidal forces are such that anything sent through is randomized, making it impossible to send information at FTL speeds? I realize that things like quantum spin, charge, etc would also have to be wiped to prevent information from being transmitted, is something liek this physically possible, or just a load of writer crap?

And yes, there are uses for that kind of wormhole - it would be a very effective generator.

Forgetting all the other problems that arise with these sorts of solutions, the answer is yes and no--depending on your definition of causality.

We might use a strict definition of causality that requires observers in all frames to perceive events ordered cause preceding preceding effect. Causality is violated always by wormholes with this definition, as there is always at least one frame in which an observer will see a traveler arrive at his destination before witnessing his departure.

We can also define causality such that its violation is due to closed timelike curves. In this case, you have an observer comoving coincidentally with the traveler's point of origin and say that a timelike path is closed if you see the traveler arrive at his destination before he departs.

[metavac]

EDIT: The same holds if the traveler departs at between your present and at any point in your future light cone. If you see him arrive before he goes into that wormhole, he's essentially traveled from your present (or future) into your causally connected past.

[Starglider]

I realize that things like quantum spin, charge, etc would also have to be wiped to prevent information from being transmitted

This won't help if the time the particle goes into the wormhole entrance is mapped onto the time the particle comes out of the wormhole exit by a non-random function; you'd still be able to send information FTL/back in time by varying the amount of mass/energy that comes out of the wormhole per unit time. In fact I don't think any sort of randomisation will help in the general case, because the total amount of mass/energy sent through over the lifetime of the wormhole is always a free variable that can send arbitrary information FTL if the lifetime of the wormhole is shorter than the time light would take to traverse the normal space between the endpoints.