we are all travelers of time... traveling at exactly 60 minutes per hour. eeh? so time travel is possible.... no need for doc and his delorean.
the brute force answer is to modify entropy. a more complete answer will have to wait for a deeper understanding of 9-dimentional physics (not the same 9 as in the 11 of string theory, although there might still be a couple of extra's floating around not attatched to one of the three fraimes of reference of 3 (+ the two vectors of the other two that appear in each) familarly cartizen dimentions each).