Can wormholes be used for faster-than-light travel?

[Pragz]

Okay, I'm trying to get a grasp of how exactly wormholes function, how they form, etc. Please correct any and all flaws/mistakes in my understanding and further educate me, if you please. :)

1. A wormhole could, theoretically, span any distance. Though the greater the distance (relative to our view and distance measurement of the cosmos from earth), the larger the black and white holes creating it would have to be.
   
2. In order to be able to successfully travel through a wormhole, one end would have to be formed from a black hole (the side of entrance) and the other a white hole (the side of exit). Internally would need to be a ring of some kind of matter with negative mass but positive surface pressure to prevent it from collapsing. Theoretically, though, this kind of exotic matter would not be required? If you timed it right you could pass through safely before it collapsed?
   
3. The travel time would be almost (if not) instantaneous, correct? Certainly faster than any kind of travel produced from our technology these days?

My mind is drawing a blank on the other questions and concerns I had. I'll probably add more by tomorrow.

Thanks for any and all help!

 

[Nabeshin]

1) No, not really. If we're talking about Einstein-Rosen bridges such as those created by black holes, the mass of the holes have nothing to do with the wormhole. Although, do note that these solutions are not traversable in the sense that they could never, not even in theory, be used for travel. A much milder class of wormholes is usually what is referred to when people speak of wormhole travel.

2) Again, you do not need black/white holes, but the bit about some type of exotic matter is correct. The bit is that a wormhole solution is not very friendly to pertubations. That is, I know some configuration of mass/energy that will produce a wormhole solution. However, when I add in the extra effect of a (say) person, the solution suddenly collapses (sometimes into a black hole). That's where the exotic energy is. There are a whole bunch of theorems and results on this point, the sum of which is that it's generally believed that ANY solution that has the properties we normally want out of a wormhole will require exotic matter. You cannot hope to "jump through before it collapses" because it is your presence that affects the collapse in the first place! I.e the closer you get, the more you are forcing it to collapse.

3) The travel time can be made arbitrarily short or long in the mathematical model of these wormholes. That's the rub with wormholes. If you allow them, then one can travel (arbitrarily fast) between two causally disconnected points, thus transferring information faster than the speed of light, and we all know paradoxes from special relativity this kind of thing causes.