Saturn's low density allows it to theoretically float on water

Saturn is the only planet in the solar system with an average density lower than that of water. While water has a density of approximately 1g/cm³, Saturn's density is roughly 0.687g/cm³, making it about 30% less dense than water.

This unique characteristic is due to the planet's composition, which consists primarily of hydrogen (96%) and helium (4%), the two lightest elements in the universe. Although Saturn is massive—with a mass approximately 95 times that of Earth—its enormous volume and gaseous makeup result in a low overall density.

Theoretically, if a sufficiently large body of water existed, Saturn could float. To accommodate the planet, which has an average diameter of approximately 116,460 km, a container would need a diameter of at least 120,000 km.