Time Travel and Warp Drives

Sci-fi makes it look so easy. Receive a distress call from Alpha Centauri? No problem: punch the warp drive and you're there in minutes. Facing a catastrophe that can't be averted? Just pop back in the timestream and stop it before it starts. But for those of us not lucky enough to live in a science-fictional universe, are these ideas merely flights of fancy-or could it really be possible to travel through time or take shortcuts between stars? Cutting-edge physics may not be able to answer those questions yet, but it does offer up some tantalizing possibilities.