Everything you need to know about the Rings of Saturn. Credit: NASA

How Well Do You Know Planet Saturn? Here Are 10 Key Facts

How well do you know the rings of Saturn?


Everyone knows that Saturn, the sixth planet and the second largest after Jupiter, has the most luxurious ring system in the entire solar system. Of course, other planets also have rings, such as Jupiter and Neptune, and astrophysicists predict that in some 20-40 million years Mars will also have them.

But all these rings cannot be compared with those of Saturn. The main ring system alone (C, B, A) is 60,000 kilometers wide, equivalent to the radius of the planet. Together with the fainter rings, it extends for more than 12 million kilometers.

What are the rings of Saturn called?

The main systems were named in Latin letters in the order they were discovered. That is why when counting from the upper layers of the atmosphere, the rings are arranged as follows: D, C, B, A, F, G, E. In addition, there are rings named after the planet’s satellites: Janus-Epimetheus and Phoebe.

How many rings does Saturn have?

Answering the question of how many rings Saturn has is not easy – it depends on how you look at them. For example, with a ground-based telescope, you are likely to see a couple of rings, while Cassini can easily distinguish gaps inside large rings and count dozens of formations. Officially, there are seven but more than 30 have been named already and there probably will be more in the future too.

Origin of the rings

There are different theories about the origin and age of the rings. Some of them suggest that the age of the rings is only 100 million years old – about two percent of the age of the Solar System. In other versions, the rings may be the same age as Saturn itself.

One popular theory is that the rings were once a relatively large moon that orbited too close to the planet. This caused it to be destroyed by Saturn’s gravity. The total mass of material in the planet’s rings is estimated at 3×1019 kilograms, a thousand times less than the mass of the Earth’s moon.

Most of the rings are made of ice, but the composition of other components, in particular, giving them an orange-pink hue, is still unknown.


Saturn's D-ring (dim). Credit: NASA/JPL
Saturn’s D-ring (dim). Credit: NASA/JPL

Let’s start with the closest ring to Saturn – D. Despite the fact that it is rather dim and does not belong to the main ring system, its proximity to the giant creates unusual patterns on it. The inner edge of the ring is about seven thousand kilometers from the clouds of the planet: on the scale of the Earth, it would be located only twice as high as the ISS, 800 kilometers above the surface.

The width of the ring is 7.5 thousand kilometers. When approaching it in 1980, Voyager 1 noticed several separate rings in it, which, upon closer inspection, turned out to be waves.

It is worth noting that the thickness of the rings is small, especially compared to the width – in many cases, it does not exceed a few meters. The height of the waves ranged from two to twenty meters. Physicists say that the source of the waves is a gravitational perturbation, for example, from a passing comet – this was observed later in the rings of Jupiter after the fall of the comet Shoemaker-Levy 9.


The inner region of the C-ring. A little to the right of the center is the Colombo Gap. Credit: NASA/JPL
The inner region of the C-ring. A little to the right of the center is the Colombo Gap. Credit: NASA/JPL

Immediately after the D-ring is the bright C-ring, 17.5 thousand kilometers wide. It was discovered back in 1850 by American astronomers William and George Bond. Like D, waves from gravitational influences were also observed on it. The C-ring contains 1/3000 of the entire mass of the fragmentary material of Saturn’s rings.

Among the internal structures, one can single out the Colombo Gap, inside which there is a small ring that is in an orbital resonance with Titan (Saturn’s largest satellite). The gap is about 150 kilometers wide.


Outer edge of the B-ring. Credit: NASA/JPL
Outer edge of the B-ring. Credit: NASA/JPL

The next is the brightest and most massive of all the rings of Saturn – B. In terms of total mass, it is comparable to Mimas (the seventh-largest satellite of the planet), and the thickness of the object is from five to fifteen meters. The width of the B-ring reaches 25.5 thousand kilometers, about a third of the diameter of Saturn. Inside it, by the way, is the satellite closest to the giant, which has not yet received a trivial name – S / 2009 S 1.

The most notable feature of the B-ring is the vertical formations on its outer edge. They are over 2.5 kilometers tall – Cassini spotted them from the long shadows they cast during the Saturnian equinox.


Encke gap in the A-ring. Credit: NASA/JPL
Encke gap in the A-ring. Credit: NASA/JPL

At a distance of more than 60 thousand kilometers from the surface of Saturn is the A ring – the outermost of the main ring system. It is dimmer than ring B, and 7 times lighter than it. The width of the object is 14.6 thousand kilometers, the thickness is 10-30 meters. It is believed that this is one of the youngest rings of Saturn – this is indicated by the uneven distribution of temperature in it.

Inside the A ring, there are several relatively large satellites: 20 km Pan, 7 km Daphnis, and 32 km Atlas. Their gravitational influence shapes the edges of the object. Like inside other rings, it has large gaps, for example, the 325-kilometer Encke Gap.


The F-ring of Saturn and Prometheus on the left. Credit: NASA/JPL
The F-ring of Saturn and Prometheus on the left. Credit: NASA/JPL

At a distance of 2.6 thousand kilometers from the outer edge of the A-ring and 140 thousand kilometers from the center of Saturn is the most variable ring of Saturn – F. With a width of only 30-500 kilometers, it attracts the attention of astronomers as an unusual dynamic system. The F-ring is gravitationally held by the “shepherd” moons Prometheus and Pandora.

According to one theory, it arose during the partial destruction of two satellites that collided with each other, which then became “shepherds”. In addition, another small satellite was found inside this ring, introducing additional difficulties to the dynamics of the object.


Shadow of Saturn on the G-ring. The arch near Aegaeon stands out brightly. Credit: NASA/JPL
Shadow of Saturn on the G-ring. The arch near Aegaeon stands out brightly. Credit: NASA/JPL

Between the F and E rings is a dim G-ring (166-175 thousand kilometers from the center of Saturn). Its width is about nine thousand kilometers. Near its outer edge is the half-kilometer satellite Egeon, which has gathered around itself a small dense arch made of ring material, extending for one-sixth of the circle.


Enceladus and the E-ring. Credit: NASA/JPL
Enceladus and the E-ring. Credit: NASA/JPL

The penultimate of Saturn’s rings is the E-ring. It is located between the orbits of Mimas and Titan (180-480 thousand kilometers from the center of the gas giant). The thickness of the ring is more than 2000 kilometers, and the main source of material for it are the geysers of Enceladus.


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Written by Vladislav Tchakarov

Hello, my name is Vladislav and I am glad to have you here on Curiosmos. As a history student, I have a strong passion for history and science, and the opportunity to research and write in this field on a daily basis is a dream come true.

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