Grace discovers he is in another solar system

While examining the ship's navigation screens, Grace notices that the star he is observing is rotating much faster than the sun. He calculates that the star's rotation period is only about two days, far faster than the sun's 25-day rotation. This leads him to the stunning realization that he is not in Earth's solar system but in the Tau Ceti system, twelve light-years away. The discovery confirms the success of the Hail Mary's interstellar journey and underscores the immense distance from home, heightening the stakes of his mission.