This idea was expounded upon in a story called "The Pusher" by John Varley. The Pushers travel in the near-light-speed ships (pushing c) but they don't interact with the people of earth much because the people are all long dead when they return from their few months in space. But there is one, who, when on earth leave, finds a young girl and gives her a glowing red plasma ruby (a by product of the near-light drive) which is a magical gift for her. When he returns, she is in her 30's but he can make contact with her and surprise her by giving her another ruby. In this way he has someone to talk to on his stays on earth.