This phrase refers to a novel, likely of a science fiction or romance genre, dealing with a relationship challenged by physical distance, possibly interstellar. An example might be a story about a young man living on Mars and a young woman living on Earth who develop a relationship online.
Such narratives can explore the impact of technology on relationships, the challenges and possibilities of long-distance communication, and the human desire for connection despite geographical or even interplanetary barriers. They can also delve into the social and psychological effects of isolation and the importance of community. Exploring these themes through fiction provides a unique lens for understanding the evolving nature of human connection in an increasingly technologically driven world.