Time Dilation?

 

Commander Henry Hatfield was an amateur astronomer and a contemporary of Patrick Moore. A very long time ago, Commander Hatfield told me in conversation that, in his opinion, the time gained through time dilation on an outward interstellar journey would be lost on the return journey so that, at the end of a round trip, if a hundred years had passed on Earth, then a hundred years, not some shorter period of time, would also have elapsed for the astronauts.

My Comments

(i) I am neither a physicist nor a mathematician so I really cannot comment. However, I get the impression that most people with any knowledge of the subject do not accept Commander Hatfield's view. And, indeed, how can the universe know whether we are making an outward or a return journey?

(ii) This does not matter for Poul Anderson's Tao Zero or The Boat Of A Million Years because their characters do not return to Earth. However, Commander Hatfield's view, if valid, would make nonsense of Anderson's Starfarers which is why I raise the issue here. 

Good night.