We can't travel back in fantasy.
Time does not exist out side the human construct. We made it up. What we call time helps us measure our experience. But nothing more.
People get sidestepped into believing time exists as a physical entity because we've invented clocks.
In 2002 scientists carried out an amazing experiment, which showed that pairs of particles knew in advance what its twin would do in the future. Somehow, the particles knew what the researcher would do before it happened, as if there were no space or time between them. More recently (Science 2007), scientists shot particles into an apparatus, and showed they could retroactively change something that had already happened. The particles had to decide what to do when they passed a fork in the apparatus. Later on, the experimenter could flip a switch. It turns out what the observer decided at that point, determined what the particle did at the fork in the past. The knowledge in the observer's mind is the only thing that determines how they behave.