Marvin, a 10-year-old boy who lives in a lunar colony, is a dynamic protagonist and round character whose journey of discovery and understanding provides the basis for the story, developing the theme of Coming of Age as an Individual and a Species. He is initially a passive observer and passenger as his father transports them to their destination. His reactions are those of a young boy: excitement at seeing areas of the colony that he has never visited before and at traveling on the surface of the Moon. His response to seeing stars is to remember the nursery rhyme “Twinkle Twinkle, Little Star”—a child’s frame of reference.

However, as Marvin realizes why his father has brought him to look at Earth and hears his father’s message, he begins to display greater maturity, turning his attention from his immediate surroundings to his role as a member of the human species. His mood is somber by the end of the story, when he has realized his duty to preserve Earth’s legacy so that his distant descendants might someday be able to return. As he leaves to return to the colony, he chooses not to look back at Earth, knowing that it will never be a reality for him and choosing to face the future with mature resolve.