Final answer:
In the twin paradox scenario with Luke and Leia, as Leia travels at relativistic speeds, she ages less than Luke, who stays on Earth. The age difference increases due to special relativity and the effect of time dilation.
Step-by-step explanation:
In the twin paradox scenario involving Luke and Leia, Leia, the astronaut aging less than her Earth-bound twin, Luke, is the correct outcome when considering special relativity and time dilation. This occur because Leia travels at a high velocity relative to Earth.
For example, if Leia travels to another star system and back, with each trip taking 1 year from her perspective and assuming a velocity high enough that 2 years for her equates to 60 years on Earth, she would age only 2 years, becoming 42 years old.
Meanwhile, Luke, who remains on Earth, would experience the passage of 60 years and, if still alive, would be 100 years old, given that he was the same age as Leia when she left. The age difference increases as Leia travels faster because time passes more slowly for her relative to Luke.