The sixth planet from the Sun, Saturn is a gas giant that’s best known for its striking icy rings. How old are the rings, and how are they changing over time? And what’s up with Saturn’s mysterious hexagon-shaped storm in the north polar region? In this episode of Gravity Assist, NASA’s Planetary Science Director Jim Green talks with Cassini Project Scientist Linda Spilker about the ringed planet, its fascinating moons and propeller-like features, and the most startling discoveries from NASA’s Cassini mission. Transcript Jim Green:Our solar system is a wondrous place with a single star, our Sun, and everything…