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Saturn's Rings


In pictures, Saturn's rings look a lot like the solar system's largest parking lot - a wide, flat surface almost as wide as the distance between the Earth and Moon. That's a lot of empty parking spaces.

Why not just park a spacecraft there to study Saturn and its moons?

Color image of the brownish gas planet Saturn and its rings.
Image to right: Saturn's rings only look solid. They are actually masses of debris forced by gravity into tight rings. Credit: NASA

Truth is, the rings only look solid. They are really a jumbled mess made up of millions and millions of pieces of ice and rock, ranging in size from tiny grains of dust to chunks bigger than a house.

Recent images sent back from Cassini - the sharpest ever taken - show that the rings may be the solar system's largest traffic jam.

Black and white close-up image of particles lumped together in Saturn’s A ring.
Image to left: A close-up of Saturn A ring taken by the Cassini spacecraft on July 1, 2004. Credit: NASA

"We do not see individual particles but a collection of particles, like a traffic jam on a highway," says Dr. Carolyn Porco, leader of the Cassini imaging team. "We see a bunch of particles together, then it clears up, then there's traffic again."

Saturn and several of its moons hold the whole jumble together in a powerful gravitational grip. Moons like Pan, Atlas and Pandora are called shepherd moons because they herd particles into Saturn's rings. The moons also create gaps and twisting wave patterns.

So if the ring particles do have solid surfaces, why not land on one?

"You could be really daring and have the spacecraft try to land on a single large chunk within the rings, but with all the other pieces flying around, it would be a pretty dangerous place," explains Dr. Marc Rayman, a scientist at NASA's Jet Propulsion Laboratory. "I think that it's probably better not to try to land there but to continue to study them from a safe distance."

Scientists can learn plenty studying the rings from a distance. In fact, the rings are kind of like a model of the early solar system.

"The small moons embedded in the rings close in to Saturn interact with the rings that is similar to the interactions that likely occurred in the early solar system itself," says Dr. Amanda Hendrix, a planetary scientist. "The moons sweep up and sculpt the rings and release ring material. They create waves and establish resonances in the rings. And so studying the rings is like studying the early solar system and the formation of the planets.

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Related Links

Cassini-Huygens home page
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Missions to Saturn
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Office of Space Science

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