What best explains the darkness of the rings beyond Saturn's?

Answer 1

Saturn's rings are more prominent than the rings of planets behind them because of their size, composition, and how they form. Astronomers discovered the darkened rings beyond Saturn on Uranus and Neptune by noticing that the stars behind the planet darkened before it actually passed in front of them.

Answer 2

The darkness of the rings beyond Saturn's main ring system is likely due to the presence of smaller, more widely spaced particles that do not reflect as much light as the larger particles in the main rings. These smaller particles may be composed of different materials or have a different composition that affects their reflective properties, resulting in a darker appearance. Additionally, variations in particle density and composition throughout the rings can contribute to differences in brightness.