Why does Saturn’s rings periodically disappear for an earthly observer?

Twice during the period of Saturn’s revolution around the Sun (29.46 years), its rings are facing the Earth with an edge. Since the thickness of the rings is small (according to various estimates, 1.5-3 km), they become invisible to the terrestrial observer at this time.

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.