Summary
Highlights
Saturn is the second-largest planet, about one-third the size of Jupiter, with a mass almost 100 times that of Earth and a diameter 10 times Earth's. It's less dense and 'puffier' than Jupiter, primarily composed of hydrogen and helium.
Saturn's atmosphere is cooler and deeper than Jupiter's, with frozen ammonia gas obscuring lower cloud layers, making its belt-zone circulation less obvious. Internally, it features layers of liquid metallic hydrogen and a large layer of gaseous hydrogen, unlike Jupiter. It might also have a rocky, metallic core and a layer of liquid or solid water near the core.
Saturn experiences storms visible near its surface. A distinctive feature is a hexagonal jet stream surrounding its northern pole.
Saturn is famous for its extensive ring system, including the Cassini division. The main rings span 100,000 kilometers in width but are only a couple of hundred meters thick, making them incredibly wide and thin, like a piece of paper in comparison to its width. They are not solid but composed of countless individual ice and carbon compound particles orbiting Saturn.
Moons within the ring system, known as shepherd moons, contribute material and shape the rings through their gravitational influence. The rings are believed to form from objects like comets or loosely bound asteroids being torn apart by Saturn's tidal forces when they enter its Roche limit. The rings are not permanent and dissipate over time due to sunlight and friction, but their replenishment by moons makes them a continually evolving feature.
Saturn has numerous moons, some formed with the planet and others captured. Most larger moons are cold, heavily cratered objects. Enceladus, however, shows signs of a subsurface liquid water ocean, similar to Europa, making it a potential site for life. The most prominent moon is Titan, larger than Mercury, possessing a dense nitrogen atmosphere – the only moon in our solar system known to have one.
Titan's atmosphere and surface are unique due to its extreme cold. Methane forms clouds and rains onto the surface, creating rivers, lakes, and oceans of liquid methane and ethane. The Huygens probe revealed river valleys, dunes, and areas with water ice, which acts like rock due to the low temperatures. Titan's atmosphere, rich in organic dust, makes it a highly interesting object of study.