Fact 2 of 10
2. Saturn would float in a giant bathtub
Saturn is so large that more than 700 Earths could fit inside it, but it is less dense than water. If a bathtub big enough existed, it would float.
A lot of gas and little mass for its size
Saturn's average density is about 0.69 grams per cubic centimeter, while water's is 1. It is the only planet in the Solar System with a density lower than water's. Earth, for comparison, has about 5.5.
This happens because Saturn is made mostly of hydrogen and helium, the lightest elements there are. It has no solid surface like Earth's: the gas grows denser with depth, until it becomes liquid under enormous pressures.
The bathtub is just an image to help understand density. In practice, no container of that size exists, and a gas planet would not stay whole in contact with water. But the comparison helps show how a giant can be light for its size.
The rings are another surprise. They extend tens of thousands of kilometers from the planet, but in many places they are only about 10 meters thick. They are made of countless pieces of ice and rock, from dust grains to blocks the size of a house.
Did you know? Saturn spins fast, with a day of about 10 and a half hours, and that is why it is visibly flattened at the poles. The flattening can be seen even in images taken with small telescopes.
