Saturn

Saturn is the sixth planet from the Sun and the second-largest in the solar system. Famous for its spectacular ring system, Saturn is a gas giant with a diameter of 116,460 km, about 9.5 times that of Earth. Despite its enormous size, Saturn is the least dense planet in the solar system -- with a density of only 0.687 g/cm³, it would theoretically float if placed in a body of water large enough to hold it. Like Jupiter, Saturn is composed mostly of hydrogen and helium. Saturn's iconic rings are the most extensive and visible of any planet. They extend up to 282,000 km from the planet's center but are remarkably thin, averaging only about 10 meters in thickness. Composed primarily of ice particles ranging from tiny grains to chunks the size of houses, along with rocky debris and dust, the rings are thought to be relatively young in astronomical terms -- perhaps only 10 to 100 million years old. The rings are organized into distinct bands separated by gaps, the most prominent being the Cassini Division. Saturn has 146 known moons, the most of any planet in the solar system. Its largest moon, Titan, is the second-largest moon in the solar system and the only moon with a dense atmosphere and stable bodies of liquid on its surface -- though those lakes and seas are filled with liquid methane and ethane rather than water. Another moon, Enceladus, shoots geysers of water ice from its south pole, indicating a subsurface ocean that could potentially harbor life. The Cassini-Huygens mission (1997-2017) revolutionized our understanding of the Saturn system over its 13 years in orbit.