If you travel close to the speed of light, you experience a phenomenon known as time dilation. Your motion through space and your motion through time are related by the speed of light: the greater your motion through space, the less your motion through time. Imagine you had a destination that was 40 light years away, and you were able to travel at incredibly high speeds: over 99.9% the speed of light. If you got into a spaceship and traveled very close to the speed of light towards that star, then stopped, turned around, and returned back to Earth, you'd find something odd.
Due to time dilation and length contraction, you might reach your destination in only a year, and then come back in just another year. But back on Earth, 82 years would have passed. Everyone you know would have aged tremendously. This is the standard way time travel physically works: it takes you into the future, with the amount of travel forward in time dependent only on your motion through space. - Ethan Siegel, astrophysicist
https://www.forbes.com/sites/starts...d-really-physically-be-possible/#779438bd12db