Here's why:

* Earth's Rotation: Our planet rotates on its axis, causing the sky to appear to rotate around a fixed point.

* Circumpolar Stars: Circumpolar stars are located close enough to the celestial pole (the point in the sky directly above Earth's axis of rotation) that they never set below the horizon as seen from a particular location. They appear to move in circles around the pole.

The exact stars that are circumpolar depend on your location on Earth. For example, from the North Pole, all stars are circumpolar. From the equator, there are no circumpolar stars.