Here's why:

* Differential Rotation: The Sun doesn't rotate like a solid sphere. Instead, it exhibits differential rotation, meaning different parts of the Sun rotate at different speeds.

* Equatorial Speed: The equator of the Sun completes a rotation in about 25 days.

* Polar Speed: The poles of the Sun rotate much slower, taking about 36 days to complete a rotation.

This differential rotation is a complex phenomenon that scientists are still trying to fully understand. It's thought to be driven by the Sun's internal structure and the flow of its plasma.