The following is an outline of the theoretical basis of making a time machine with a traversable wormhole (if you ignored the problems of energy feedback, grandfather paradoxes, the lack of traversable wormholes, and other practical considerations) as given by Kip Thorne in his book "Black Holes & Time Warps, Einstein's outrageous legacy", p Kip and (a very strong) Carolee hold hands through a short wormhole. Carolee takes off in a spaceship (still holding hands) and returns 10 earth-years but only 12 Carolee-hours later. Kip is watching Carolee through the wormhole, and sees her land, according to the wormhole, 12 hours later. He looks outside the wormhole, and has to wait 10 years to see her land. When she lands, she is still holding hands through the wormhole. On the other end is the younger Kip. The older Kip climbs through the wormhole to end up back with the younger Kip. (or vice-versa). What bothers me about the argument is that one assumes that the same time intervals would be occurring on both ends of the wormhole. But could it be that Carolee is holding hands with a Kip who was simply aging much faster than her? Another question, not touched on in Thorne's book: would the wormhole necessarily stay more or less the same length throughout Carolee's journey? (Wormhole metrics are beyond my capabilities to calculate these questions out.) Thanks for any insights.