How to explain the fluctuations in the brightness of asteroids?

The shape of asteroids can differ from spherical, and different parts of the asteroid can reflect sunlight in different ways, therefore, as a result of rotation, there is a fluctuation in brightness.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.