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What are Saturn's rings made of?

Saturn's rings
(Image credit: Getty)

Distant images make Saturn's rings appear to be one solid band of rock. However close flybys and studies have provided detailed images of the rings' arrangement, with precise snaps of some of the unique objects orbiting Saturn. 

Saturn's rings are an array of rocky and icy fragments, which scientists believe to be pieces of moons, asteroids and comets, according to NASA (opens in new tab). The theory is that these giant rocks were shattered into fragments under the force of Saturn's gravity. The result is a combination of huge, mountain-sized rocks and tiny particles of dust. Many of the larger objects in the planet's rings are coated in a layer of dust. 

Before 1979, scientists thought that Saturn was the only planet in the solar system with rings, according to the Encyclopedia of Physical Science and Technology (opens in new tab). Now we know that, while all the planets attract space objects into rings, Saturn's rings are the brightest and lie close together.

Saturn's bright rings carry space fragments that are younger than the planet itself. According to a 2019 report by the BBC (opens in new tab), data from the US-European Cassini mission revealed that the rings could be as young as 10 million years old and no older than 100 million years.

What are the seven rings of Saturn?

When viewed from a distance, Saturn displays seven distinctive rings, according to NASA (opens in new tab). These are simply named as the first seven letters of the alphabet. This ordering doesn't correspond to their distance from the planet, but the order in which they were discovered. 

Each ring contains orbiting matter. Combined, the rings stretch across thousands of miles of space.

The first three rings to be discovered (A, B and C) are the easiest to spot, due to them being bright, main rings of the planet, according to NASA Science (opens in new tab). Meanwhile, the D ring is extremely dim and lies closest to the planet. The E ring is the largest and outermost ring, spanning 621,370 miles (about one million kilometers) and lying next to another faint ring, G. Saturn’s F ring is made up of many narrow rings. As each ring contains multiple kinks and bright clusters, this ring can produce a braided pattern, according to Space.com (opens in new tab)

The mini moons of Saturn's rings

Small, low density moons can be found in Saturn's rings:

When were Saturn’s rings discovered?

When Galileo Galilei became the first person to lay eyes on Saturn's rings in 1610, he was unsure what they were, according to the European Space Agency (opens in new tab). Looking through his telescope, Galileo described them as ears, as they seemed to appear on opposite sides of the planet. 

45 years later, it was a Dutch astronomer called Christiaan Huygens who correctly proposed that these were rings, in the shape of disks, that encircled Saturn. According to NASA (opens in new tab), Huygens was able to observe finer details than Galileo could as he had a stronger telescope. 

Additional resources

To learn more about how Saturn is losing its rings, you can watch this video by NASA Goddard (opens in new tab). Additionally, read all about the Cassini mission on this NASA Science (opens in new tab) page.

Bibliography

"Saturn Ring". Encyclopedia of Physical Science and Technology (Third Edition), (2003). https://www.sciencedirect.com/topics/earth-and-planetary-sciences/saturn-ring (opens in new tab)

"Structure, stability and evolution of Saturn's rings". Nature (1984). https://www.nature.com/articles/309333a0 (opens in new tab)

"The Structure of Saturn's Rings". Saturn from Cassini-Huygens. https://link.springer.com/chapter/10.1007/978-1-4020-9217-6_13 (opens in new tab) 

Ailsa is a staff writer for How It Works (opens in new tab) magazine, where she writes science, technology, history, space and environment features. Based in the U.K., she graduated from the University of Stirling (opens in new tab) with a BA (Hons) journalism degree. Previously, Ailsa has written for Cardiff Times magazine, Psychology Now and numerous science bookazines. Ailsa's interest in the environment also lies outside of writing, as she has worked alongside Operation Wallacea (opens in new tab) conducting rainforest and ocean conservation research.