1. As seen by Earth-based observers, the intervals between successive edge-on presentations of Saturn’s rings alternate between 13 years, 9 months and 15 years, 9 months. Why are these two intervals...

1. As seen by Earth-based observers, the intervals between successive edge-on presentations of Saturn’s rings alternate between 13 years, 9 months and 15 years, 9 months. Why are these two intervals not equal?

2. Compare and contrast the internal structures of Jupiter and Saturn with the internal structures of Uranus and Neptune. Can you propose an explanation for why the differences between these two pairs of planets occurred?