how possible is time travel?

[winchy]

i would just like to know where to get some good info on possble time travel and some people personal views on it. Thanks.

[atyy]

The best science I know about this is Morris and Thorne's traversable wormholes. Kip Thorne has a popular science book "Einstein's Outrageous Legacy" which very entertaining and also very scientific (ie. careful to distinguish what it speculation from fact).

Some stuff on arXiv:
http://arxiv.org/abs/gr-qc/9803098

This issue is also often discussed with quantum teleportation. The most important restrictive theorem there is called the "no cloning" theorem.

[George Jones]

For an excellent, non-technical reference, have a look at the second edition of Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction by Paul Nahin. This is a wonderful book that is written for the educated layperson.

Physicist (and relativist) Kip Thorne wrote a foreword for the second edition of this book, and here's a quote from this foreword: "It now is not only the most complete documentation of time travel in science fiction; it is also the most thorough review of serious scientific literature on the subject - a review that, remarkably, is scientifically accurate and at the same time largely accessible to a broad audience of nonspecialists."

As atyy said, wormholes can be used to generate closed timelike curves, but wormholes require exotic material. I wrote about Morris-Thorne wormholes and closed timelike curves here (requires knowledge of special relativity):

http://groups.google.ca/group/sci.physics.research/msg/ca7fd4ed9d282afb?dmode=source.

I also have written about rotating black holes and time travel (requires knowledge of general relativity),

http://www.physicsforums.com/showthread.php?p=1166705#post1166705,

but this possibility likely is blocked by stuff that falls into the black hole.

See also this post:

http://www.physicsforums.com/showthread.php?p=1068268#post1068268.