what does the relativity of time have to do with time travel. yes, the faster you go, the slower time passes. however, that is only relative to the person't that surround you, not to YOU. Time will pass the same for you going light speed as for the guy sitting and watching. it's just the time of the two rapported to eachother that differs and is relative.
time travel involves the eternal problem. the paradox: two opposing sitiations simultaneously available. Like me meeting myself if in travel into the future or the past...because, you see. time travel (as we percieve it, but shouldn't) is actually taking the person in discussion from 'here' and take it to 'there', instead of taking the person from 'now' and take it to 'then'. That's when the paradox occurs.
if someone dies and everyone mourns him, you go back, save him, then come back to your time..where that someone lives, and no-one mourned him. how is that possible...it's like the reactions to his death never happened in the first place. and you're the only one who knows it. fact is...the world does not revolve around the supposed time traveller. as it would be in that case.
my opinion is that it's not possible....not as we so far percieve it anyway 🙂..us the common folk