Re: Using alternat universes as a medium of cheating the Big Crunch.

Tom,

Interesting question. Einstein-Rosen Bridges, or "wormholes", are a solution of the Schwarzschild geometry, which deals with the curvature of spacetime around a spherical mass. In this solution, the event horizons of a black hole and a white hole create a connection between two universes. There is an excellent resource on wormholes and related topics here.

As you will see on those pages, there are some major problems with using wormholes, including:

• Wormholes may not actually exist. Although they are a solution of Einstein's equations, they require the existence of a white hole, which is essentially a black hole running backwards in time, spitting out matter rather than sucking it in. We have never seen evidence for white holes, which is in some ways a comforting thing, since it would violate the second law of thermodynamics.
• If it were possible to create wormholes (normal stars can't make one) they would be unstable and fly apart. It might be possible to keep one open by lining the inside with some sort of exotic matter (with negative mass, and positive surface pressure), but there is no evidence such matter exists.
• If you did create a wormhole and make it stable, you could get into one, but you could never get out either side unless you entered the wormhole at a speed faster than light, a relativisitic impossibility. You would be trapped inside the wormhole, able to see light coming in from both universes, but never able to escape, or send out any information to others.

But I wouldn't worry about it all too much. Current evidence suggests that the "big crunch" will never happen, and the universe will simply keep expanding forever. Take a look at Ned Wright's Cosmology FAQ for some of the best-presented cosmology information I have seen on the net.

Of course, if this is true that presents us with the problem of how to keep surviving into eternity after all of the stars burn out. But we won't have to start dealing with that issue until many billions of years from now, so I figure we will probably learn a thing or two by then... :-)

Hope this helps.

Sam Silverstein