Student Features

Saturn: Lord of the Rings
07.01.04
In 1610, Galileo used a new invention -- a simple telescope -- to look at Saturn. When he viewed the planet for the first time, he saw something strange. He thought he saw three stars together, a big one in the middle of two little stars. He knew they weren't really stars, but what were they?

Saturn's rings.
Image to right: We can see Saturn's rings at different angles at different times. Credit: NASA

It turned out that Galileo was the first to see the rings of Saturn!

Scientists have been learning about Saturn's rings ever since. In 2004, NASA's Cassini spacecraft will reach Saturn to learn even more.

How did the rings form? Have they been there as long as Saturn? Of what are the rings made? Why don't other planets have such big, bright rings? Let's take the questions one at a time.

How did the rings form? Some scientists believe the rings are dust and particles that were thrown into space around Saturn when something hit the surface of the planet. Other scientists believe that the rings are from a moon of Saturn that broke into pieces and started orbiting around the planet. When Cassini arrives, maybe we'll learn which idea is correct.

Are the rings as old as Saturn? The rings around Saturn are very bright. Scientists think that since the rings are so bright, the rings must not be very old. The reason for this is because the particles that make up the rings would collect space dust and would get dull just like dust on Earth dulls our furniture. Cassini will measure the space dust on the particles when it visits Saturn.

Saturn rings side view
Image to left: Saturn's rings are very thin. Astronomers using the Hubble Space Telescope captured this image of the rings edge-on in 1995. The bright object on the left is one of Saturn's icy moons. Credit: NASA

Of what are the rings made? Scientists agree on the answer to this question. The rings are bits of matter, some so small you couldn't see them and some so large, they would be called boulders. All of the bits are caught in the gravitational force of Saturn and stay in orbit. But who knows what surprises Cassini will find?

Why don't other planets have big, bright rings?

Jupiter, Neptune and Uranus all have rings. Jupiter's rings are much smaller and very dark compared to Saturn's rings. Jupiter's rings would be much older than Saturn's rings if the scientists are right when they say brighter rings are young because they haven't gotten dusty.

Neptune and Uranus have very dark, almost black, rings. Here again, the rings would be much older than Saturn's rings because they are so dark. Scientists aren't sure how those rings were formed, either.

In 2004 Cassini will begin to answer some of the questions we have about Saturn's rings. Of course, every answer will lead to more questions. But whatever the answers may be, the beauty and splendor of Saturn's rings are there for all to see.

But what about the big question: who is the real lord of the rings in our solar system? Without a doubt, Saturn rules! Saturn's rings are bigger, brighter and more amazing than any of the other planets' rings.