Saturn is the sixth planet from the sun in our solar system. It is the second-largest planet in our solar system (Jupiter is the largest). It has beautiful rings that are made mostly of ice chunks (and some rock) that range in size from the size of a fingernail to the size of a car. Saturn is made mostly of hydrogen and helium gas.
Saturn is visible without using a telescope, but a low-power telescope is needed to see its rings.
Size and Shape
Saturn is about 74,898 miles (120,536 km) in diameter (at the equator at the cloud tops). This is about 9.4 times the diameter of the Earth. 764 Earths could fit inside a hollowed-out Saturn.
Saturn is the most oblate (flattened) planet in our Solar System. It has a equatorial diameter of 74,898 miles (120,536 km) (at the cloud tops) and a polar diameter of 67,560 miles (108,728 km). This is a difference of about 10%. Saturn’s flattened shape is probably caused by its fast rotation and its gaseous composition.
Saturn’s beautiful rings are only visible from Earth using a telescope. They were first observed by Galileo in the 17th century.
Saturn’s bright rings are made of ice chunks (and some rocks) that range in size from the size of a fingernail to the size of a car. Although the rings are extremely wide (over 1 million km in diameter), they are very thin (about 0.6 miles = 1 km thick).
For more information on Saturn’s rings, click here.
Mass, Gravity, and Density
Saturn’s mass is about 5.69 x 1026 kg. Although this is 95 times the mass of the Earth, the gravity on Saturn is only 1.08 times the gravity on Earth. This is because Saturn is such a large planet (and the gravitational force a planet exerts upon an object at the planet’s surface is proportional to its mass and to the inverse of its radius squared).
A 100 pound person would only weigh 108 pounds on Saturn.
Saturn is the only planet in our Solar System that is less dense than water. Saturn would float if there were a body of water large enough!
Length of a Day and Year
Each day on Saturn takes 10.2 Earth hours. A year on Saturn takes 29.46 Earth years; it takes 29.46 Earth years for Saturn to orbit the sun once.
At aphelion (the place in its orbit where Saturn is farthest from the Sun), Saturn is 1,503,000,000 km from the Sun. At perihelion (the place in its orbit where Saturn is closest to the Sun), Saturn is 1,348,000,000 km from the Sun.
The mean temperature on Saturn (at the cloud tops) is 88 K (-185° C; -290° F).
Saturn has dozens of moons (33 discovered as of August, 2004). It has 18 named moons. including Titan (the largest), Rhea, Iapetus, Dione, Tethys, Enceladus, Mimas, Hyperion, Phoebe, Janus, Epimetheus, Pandora, Prometheus, Helene, Telesto, Atlas, Calypso, and Pan (the smallest named moon of Saturn). At least a dozen others have been noted (but not named yet).
For more information on Saturn’s moons, click here.
Saturn has been visited by Pioneer 11 (in 1979) and by Voyager 1 and Voyager 2. Cassini, a spacecraft named for the divisions in Saturn’s rings, is on the way and will arrive in 2004.
Name and Symbol
Saturn was named for the Roman god of agriculture.