So, I'm certainly not a physicist but I think I've just about started to grasp the concept of relativity and spacetime - maybe. A little bit. Hopefully. Anyway, I've always felt the concept of time travel is ridiculous, or at least backwards time travel, and I was trying to prove this to myself. I'm starting to understand why time slows as you travel faster, particularly as you near lightspeed, but does this not effectively mean you cannot ever reach light speed because your relative time would stop - completely? Which I understand as being impossible because if time froze you would be stuck for all eternity and nothing would ever happen beyond that point. Now, this may be a long-winded question (sorry) but I'm hoping to get a reasonably simple answer that I can understand.