Star trails are the streaks of light created by the movement of stars across the night sky. As the Earth rotates on its axis, stars appear to move in circular paths around the celestial poles. When a long-exposure photograph is taken, these movements are captured as bright lines, showing the stars' trails over time. The length and shape of star trails depend on the exposure time and the observer's location. For instance, in the Northern Hemisphere, star trails will circle around the North Star, or Polaris, while in the Southern Hemisphere, they will revolve around the Southern Celestial Pole.