For example, if we could convert a human being into some sort of energetic medium—say light or radio waves—then place a reconverter 100,000 light years from earth, a person could step through a door here, feel as if he had come out the other side instantaneously, then step back and find that he was 200,000 years in the future. A cumbersome time machine, but it would work.
Anything can work if you pull the idea out of your ass and ignore physics.
