People say and have decently backed up that time travel is not possible by saying that you would have to rearrange every particle back to where it was. Instead of rearranging the particles of everything. What if u could take all the information and I mean every aspect and formation of every atom could be written down. What if you used the information you found out that was every part of ur previous body. step into a machine, and if possible re-arrange every single particle of the body at the exact same time. But since you lose blood cells and other stuff from getting hurt. It seems like its near impossible even though i have the concept down. This again leads back to time, "the 4th dimension" If we could find a way to negitate time it might work. If it is true that in the exact center of a blackhole, time slows down and maybe comes to a stop. Based upon that, and with information that we should be able to get in the future.