# Stable worm holes

1. May 11, 2005

### boy genius

how would you create a stable worm hole and if it is possibele how would you know where it would go to and if you could actualy put something like a remote control car through it.

2. May 11, 2005

### pervect

Staff Emeritus
I gather that it's impossible to form a wormhole classically - it had to exist already. (I don't recall the exact source for this statement, though). I'm fairly sure that I remember that Morris & Thorne proposed finding an existing wormhole and stabilizing it in their paper
"Wormholes, Time Machines, And The Weak Energy Condition", but I don't seem to be able to find a copy of this paper online.

3. May 11, 2005

### JesseM

Here's an article discussing an idea that small stable wormholes may exist naturally as a consequence of "squeezed vacuum states" shortly after the big bang:

http://www.npl.washington.edu/AV/altvw53.html

4. May 12, 2005

### Sempiternity

5. May 12, 2005

### JesseM

It's not as easy as just creating the right distribution of matter/energy though--you'd actually need to change the topology of spacetime to create a wormhole, which the classical theory of general relativity doesn't tell you how to do, although a quantum theory of gravity might. Actually, there is a caveat to this that Kip Thorne mentions on p. 496 of Black Holes and Time Warps:

Last edited: May 12, 2005
6. May 23, 2005

### Sempiternity

It's a good explination, except that what's missing is the initiation process of creating such a wormhole. When you "try to warp and twist space on macroscopic scales," how is that done? In the process where "one must tear two holes in space and sew them together," Greene Thorne speculates this as being a part of "topology-changing transitions" consisting of 3-brane manifolds wraping around the tear.

Concerning the part about a classical method, he explains that it can possibly be done by "warping and twisting of spacetime" where "time also becomes twisted up as seen in all reference frames" and the machinery "function briefly as a time machine that carries things from late moments of construction back to early moments."

However, through all of this, how does it all occur? How do you "warp and twist" spacetime in the first place? I was speculating that it might be possible to actually do so by condensing large amounts of electromagnetic energy into a small space.

From Parallel Worlds,

Last edited: May 23, 2005
7. May 24, 2005

### Spin_Network

You have more chance of hitching a ride on the back of a team of alien dolphins:https://www.physicsforums.com/showthread.php?t=76604 [Broken]

Last edited by a moderator: May 2, 2017
8. May 24, 2005

### jcsd

It seems to me that if you seek to make worm holes the one thing you require above all else is worms.

9. May 24, 2005

### Rev Prez

The problem is generating the right distribution of mass-energy. You can solve for $$T_{\mu\nu}$$ in Einstein's equation given some desired metric just as you can solve for $$G_{\mu\nu}$$ given some distribution of of mass-energy. I think you meant to say that we may need a theory of quantum gravity to determine whether a superluminal topology is physical.

Rev Prez

10. May 24, 2005

### JesseM

No, my point was that the classical theory doesn't allow you to change the topology of space just by moving matter and energy around, and a topology change is needed to create a wormhole, aside from the method Thorne described which would require a method of time-travelling during the construction.

This post by John Baez may be helpful in clarifying the difference between the metric of a spacetime and the topology:

http://www.lns.cornell.edu/spr/2001-05/msg0032747.html

Last edited: May 24, 2005
11. May 24, 2005

### Rev Prez

My bad. You're right. You do assume the manifold is connected in the desired way before calculating energy-momentum.