Some documentaries, basing on Einstein theories, mention a remote possibility of traveling through time. Some go to the extent of exemplifying time as SOLID SLICES as in a card holder.
My own approach is that time is a flat 2-d thingy: there is only the NOW. There is no past and there is no future. Everything is “saved” on a flat momentum.
You can visit (visualize) the past by going through records as in ancient documents, fossils, films, etc. You can plan the future (predict) assumed none of the possible variables involved will change value (as in constants). You can only, for certain, predict the next second in time. Everything else is left to probability.
Time is just a reference anyway. As discussed in numerous occasions, the early humans used the Moon and the Sun as time references. Later the clock was invented and, then, the calendar. But, all in all, time is just a reference not a physical matter.
In Einstein’s theory of relativity, as presented by physicists in the world, if a traveler leaves Earth at light speed and return some time later, he (her), the traveler, would have aged much less that the earthlings left behind.
Well, let’s extrapolate:
A human is sent, at light speed, from Earth (Solar System) to the next Star System which is at 4.7 light years away.
In a round trip; assumed he(her) will just boomerang back to Earth, he(her) would have traveled 9.4 light years in distance.
9.4 light years means that the trip took 9.4 years traveling at the speed of light. Therefore, the time elapsed to the traveler and to the earthlings, was only 9.4 years.
The aging on the traveler will be affected as much as the earthlings left behind and, the time, unless you want to insist that traveling at light speed is bypassing time itself, is the same.