Mary Kay Carson - Far-out Guide to Saturn

RINGMASTER

SATURNTHE JEWEL OF THE SOLAR SYSTEMhas seven mysterious and beautiful rings. These rings, made of ice, dust, and rock, range in size from a snow crystal to a house. How do we know this?

Spacecraft from Earth have visited Saturn and taught us a lot about this mysterious, faraway planet. Learn about the amazing missions, the dedicated scientists who plan them, and more far-out facts about the sixth planet from the Sun.

The Far-Out Guide to the Solar System series provides valuable information about the solar system, its planets, and mankind's quest in exploring them. This series is an excellent resource for young scientists and amateur astronomers

About the Author

Award-winning author MARY KAY CARSON has written many nonfiction books for young people and their teachers. In 2009, she received the American Institute of Aeronautics and Astronautics Children's Literature Award.

Saturn is the sixth planet from the Sun. (Note that the planets distances are not shown to scale.)

No one is sure yet how many moons Saturn has. How is that possible? Scientists keep finding more! So far, astronomers have identified sixty-one moons circling Saturn. Better telescopes and recent spacecraft missions are helping them discover more moons. You will learn lots more far-out facts about Saturn in this book. Just keep reading!

Saturn is a stunning sight. The sixth planet easily earns its nickname: the jewel of the solar system. Its amazing rings are what make it so special. Saturns rings shine and shimmer. They glow with stripes of colors highlighted with lines of shadow. The rings of Saturn make it the most recognizable planet after ours. Everyone knows Saturn because of its rings. But those same rings hold many secrets. No one knows for sure when they started circling Saturnor how they got there.

Saturn is our solar systems sparkling jewel. The Hubble Space Telescope took this image.

Saturn is a planetary ball of liquids and gases called a gas giant. You could not stand on Saturn because there is no land or solid surface. It is a cold world with hurricane-like storms and fierce winds. At least sixty-one mysterious moons also circle Saturn. Many are small icy balls far from the planet, while others are squeezed between rings. Some of Saturns moons even have water and other ingredients that life needs.

Scientists are working on solving Saturns mysteries. A spacecraft that has recently been visiting Saturn has been a big help. Cassini has no crew. It is a robotic spacecraft, or space probe. Cassini began studying Saturn, its rings, and its moons in 2004. It has made many surprising discoveries about Saturn.

Cassini took this picture when the Sun was behind Saturn. This view lights up Saturns amazing rings from behind.

FAR-OUT FACT

When Galileo first observed Saturn in 1610, it confused him. The Italian astronomer could not clearly see the rings through his small telescope. He thought they looked like two large moonsone on each side of Saturn. A few years later, Galileo sketched Saturns rings as loop-like teacup handles on either side of Saturn. In 1656, Christiaan Huygens got a better look using a more powerful telescope. The Dutch astronomer described what he saw as a thin, flat ring around the planet.

This illustration shows the Cassini spacecraft arriving at Saturn. Cassini weighs 5,712 kilograms (12,593 pounds) and is about the size of a school bus.

Saturn is more than a planet. The enormous gas giant, its seven rings, and its sixty-one or more moons make up the Saturn system. Studying the Saturn system calls for a major mission and a large spacecraft. Cassini is both. It is the biggest space probe ever sent past Mars. Cassini left Earth in 1997. It took the robotic explorer seven years to reach Saturn.

Cassini was not Saturns first visitor. Three space probes flew by the ringed planet between 1979 and 1981. But Cassini was the first to study the sixth planet for a long time. Cassini is an orbiter, a space probe that circles arounda planet. When Cassini finally reached Saturn in 2004, it settled in for a long visit.

Putting an orbiter around a planet and being able to hang out there lets scientists watch Saturn, its moons, and its rings over time, says Cassini program scientist Carolyn Porco. Getting into orbit around Saturn was not easy, however. Cassini had to pass through the planets rings first!

Saturns seven rings are not solid. They are made up of billions of pieces of ice. The rings are like a hailstorm circling the planet in a wide, thin band. The rings stretch for a distance as wide as twenty-one Earths placed side by side. Theyre as thin as tissue paper compared to their width. Saturns rings are only about twenty meters (sixty-five feet) or so thick. Some of the ice chunks that make up the rings are as big as a house. Others are as small as a single powdery snow crystal. And they are screaming around the planet at 32,000 to 64,000 kilometers (20,000 to 40,000 miles) per hour, says Porco. It is a dangerous place for a spacecraft.

The plan was for Cassini to fly through a gap between two of Saturns outer rings. Engineers hoped it could safely pass through there. Cassini had to turn its antennae away from Earth before entering the rings. For ninety long minutes, the Cassini team was out of contact with the spacecraft. Then Cassini phoned home! Cassini had made it through the gap and slipped into orbit unharmed. (The illustration shows where Cassini crossed between the rings.)

FAR-OUT FACT

Cassini is named for the Italian astronomer Giovanni Domenico Cassini (16251712). He studied the Saturn system. Cassini discovered four moons and the gap between two major rings that is now named the Cassini Division. Scientists and engineers from seventeen different countries built Cassini. In 1997, a rocket launched the space probe. Cassini then began a 3.2-billion-kilometer (2-billion-mile), seven-year journey to Saturn. Cassini orbited Saturn for more than six years, making many important discoveries about the Saturn system.

No one was happier about Cassinis success than Carolyn Porco. By the time the spacecraft reached the sixth planet, the astronomer had already spent fourteen years working on the mission. Porcos fascination with Saturn goes back even farther. She caught her first glimpse of the ringed planet through a friends telescope at age thirteen. It sparked a lifetime passion for astronomy. To know that we can know so much about our solar system and about our cosmos, for me, makes life meaningful, says Porco.