Exploring The Planets: Saturn

Saturn and its rings seen from NASA’s Cassini spacecraft in 2016. This view was taken by combining 165 images of Saturn,

while lit from the sun behind it. Photo from: NASA/JPL/Space Science Institute.

Saturn is the second-largest planet in the solar system, after Jupiter. It is best known for its

extraordinary rings, which consist of dusty chunks of ice — some the size of a house, others

the size of a grain of sand. Saturn travels around the sun at an average distance of about 890

million miles.

Saturn was named after the ancient Roman god of agriculture. His counterpart in ancient

Greek mythology was Cronus, the father of Zeus (who was the counterpart of the Roman god

Jupiter).

The planet is a popular target for amateur astronomers, because even a small telescope can

reveal the dazzling rings. To the unaided eye, Saturn looks like a bright non-twinkling point of

light. It was the most distant planet known to ancient astronomers.

Physical Features

Saturn is massive — its diameter, or distance through its center, is about 74,900 miles, which

is nine times larger than Earth’s diameter. However, Saturn is very light for its size. It would

float if placed in water.

By Encyclopaedia Britannica, adapted by Newsela staff on 08.29.17

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The planet Jupiter is Saturn’s nearest neighbor and the closest to it in size and composition.

Like Jupiter, Saturn is a kind of planet called a gas giant. It is made up mostly of gases, mainly

hydrogen and helium. What looks like a solid surface in photographs is actually a layer of

clouds. Under Saturn’s huge layers of gases is a smaller area of hot liquid metal. At its center

the planet probably has a hot, rocky core.

A system of very thin rings surrounds Saturn. The rings extend thousands of miles out from the

planet, and are made up mostly of pieces of water ice and dust.

Saturn has eight major moons and many small ones. Altogether more than 50 moons orbit the

planet. Its largest moon is Titan. Titan’s atmosphere, or the layer of gases surrounding it, is

very thick. Titan is the only moon in the solar system known to have a thick atmosphere and

clouds.

Orbit And Spin

Like all planets, Saturn has two types of motion: orbit and spin. Saturn orbits, or travels

around, the sun. It takes Saturn about 29 Earth years to complete one orbit. In other words, a

year on Saturn is about 29 Earth years.

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Saturn spins rapidly about its center. It takes the planet less than 11 hours to complete one

rotation. That is the length of a day on Saturn.

Observations And Exploration

People have observed Saturn from Earth since ancient times. In the 1970s the United States

sent three unmanned spacecraft — named Pioneer 11, Voyager 1 and Voyager 2 — to Saturn.

They were the first spacecraft to fly by the planet.

An unmanned U.S. spacecraft named Cassini began orbiting Saturn in 2004. It dropped a

European spacecraft called Huygens onto Titan. Huygens was the first spacecraft to land on a

moon other than Earth’s moon.

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