What are Saturn’s Rings Made Of?

Saturn's rings are made of billions of pieces of ice, dust and rocks. Some of these particles are as small as a grain of salt, while others are as big as houses. These chucks of rock and ice are thought to be pieces of comets, asteroids or even moons which were torn apart by the strong gravity of Saturn before they could reach the planet.

Galileo Galilei was the first to observe the rings of Saturn in 1610 using his telescope, but was unable to identify them as such.

Ring theory and observations

In 1655, Christiaan Huygens became the first person to suggest that Saturn was surrounded by a ring. Using a 50 power refracting telescope that he designed himself, far superior to those available to Galileo, Huygens observed Saturn and wrote that "It [Saturn] is surrounded by a thin, flat, ring, nowhere touching, inclined to the ecliptic" Robert Hooke was another early observer of the rings of Saturn, and noted the casting of shadows on the rings. 

In 1675, Giovanni Domenico Cassini determined that Saturn's ring was composed of multiple smaller rings with gaps between them; the largest of these gaps was later named the Cassini Division. This division is a 4,800 km-wide region between the A Ring and B Ring.

In 1787, Pierre-Simon Laplace suggested that the rings were composed of a large number of solid ringlets.

In 1859, James Clerk Maxwell demonstrated that the rings could not be solid or they would become unstable and break apart. He proposed that the rings must be composed of numerous small particles, all independently orbiting Saturn. Maxwell's theory was proven correct in 1895 through spectroscopic studies of the rings carried out by James Keeler of Allegheny Observatory.

The rings are named alphabetically in the order they were discovered. The main rings are, working outward from the planet, C, B and A, with the Cassini Division, the largest gap, separating Rings B and A. Several fainter rings were discovered more recently. The D Ring is exceedingly faint and closest to the planet. The narrow F Ring is just outside the A Ring. Beyond that are two far fainter rings named G and E. The rings show a tremendous amount of structure on all scales, some related to perturbations by Saturn's moons, but much unexplained.






Saturn is sometimes called the ”Jewel of the Solar System” because its ring system looks like a crown. The rings are well known, but often the question ”what are Saturn’s rings made of” arises. Those rings are made up of dust, rock, and ice accumulated from passing comets, meteorite impacts on Saturn’s moons, and the planet’s gravity pulling material from the moons. Some of the material in the ring system are as small as grains of sand, others are larger than tall buildings, while a few are up to a kilometer across. Deepening the mystery about the moons is the fact that each ring orbits at a different speed around the planet. 
 
Saturn is not the only planet with a ring system. All of the gas giants have rings, in fact. Saturn’s rings stand out because they are the largest and most vivid. The rings have a thickness of up to one kilometer and they span up to 482,000 km from the center of the planet.

Below is a list of the main rings and gaps between them along with distances from the center of the planet and their widths.

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• The D ring is closest to the planet. It is at a distance of 66,970 – 74,490 km and has a width of 7,500 km.
• C ring is at a distance of 74,490 – 91,980 km and has a width of 17,500 km.
• Columbo Gap is at a distance of 77,800 km and has a width of 100 km.
• Maxwell Gap is at a distance of 87,500 km and has a width of 270 km.
• Bond Gap is at a distance of 88,690 – 88,720 km and has a width of 30 km.
• Dawes Gap is at a distance of 90,200 – 90,220 km and has a width 20 km.
• B ring is at a distance of 91,980 – 117,580 km with a width: 25,500 km.
• The Cassini Division sits at a distance of 117,500 – 122,050 km and has a width of 4,700 km.
• Huygens gap starts at 117,680 km and has a width of 285 km – 440 km.
• The Herschel Gap is at a distance of 118,183 – 118,285 km with a width of 102 km.
• Russell Gap is at a distance of 118,597 – 118,630 km and has a width of 33 km.
• Jeffreys Gap sits at a distance of 118,931 – 118,969 km with a width of 38 km.
• Kuiper Gap ranges from 119,403 -119,406 km giving it a width of 3 km.
• Leplace Gap is at a distance of 119,848 – 120,086 km and a width of 238 km.
• Bessel Gap is at 120,305 – 120,318 km with a width of 10 km.
• Barnard Gap is at a distance of 120,305 – 120,318 km giving it a width of 3 km.
• A ring is at a distance of 122,050 – 136,770 km with a width of 14,600 km.
• Encke Gap sits between 133,570-133,895 km for a width of 325 km.
• Keeler Gap is at a distance of 136,530-136,565 km with a width of 35 km.
• The Roche Division is at 136,770 – 139,380 km for a width 2600 km.
• F ring is begins at 140,224 km, but debate remains as to whether it is 30 or 500 km in width.
• G ring is between 166,000 – 174,000 km and has a width of 8,000 km.
• Finally, we get to the E ring. It is between 180,000 – 480,000 km giving it a width of 300,000 km.

As you can see, a great deal of observation has been dedicated to understanding and defining Saturn’s rings. Hopefully, having the answer to ”what are Saturn’s rings made of” will inspire you to look more deeply into the topic.