When you look at images of Saturn, one thing that immediately catches your eye is its extensive ring system. The rings of Saturn host more than 60 moons that intermittently appear, and numerous rocks and dust particles.
How many rings does Saturn have? More importantly, why does Saturn have this ring system? Where did they come from, and will they remain the same forever? While we don’t know the definite answers to these questions, scientists are making progress in understanding more about Saturn’s rings.
In this article, we will touch upon all of the above questions, which will give you the knowledge before you embark on a Saturn-hunting trip! Let’s begin.
How Many Rings Does Saturn Have?
Saturn has a complete ring system, and each ring has multiple sub-rings. They are named according to the letters in the alphabet: A through G, but their distance from Saturn is not in any particular direction; they were named in the order that they were discovered.
The three main ones are A, B, and C rings. These are densest of all and are more easily visible from Earth. The A and B rings are on the outer edges of Saturn’s ring system.
They are divided by the Cassini Division, which appears as a band of darkness in images. A ring is darker than the B ring, mostly because it is denser.
In the image below, A ring is the outermost, then there is the dark Cassini Division. The light ring after the division is B ring, and the darker zone inside that is C ring.
Viewing the C ring is hard without a large telescope since it is fainter and farther—on the inner edge of the B ring. The D ring is closest to Saturn and consists of very tiny particles, it is practically impossible to see with a backyard scope.
As we said earlier, the rings are labeled for the order of their discovery, which is why E ring is outside of A, farthest of all the rings from Saturn. Rings F and G are between E and A.
While A, B, and C rings can be seen with telescopes, D through G rings can only be seen by a spacecraft.
Why Does Saturn Have Rings?
Saturn’s rings are formed from celestial bodies that have broken into pieces when they entered inside Saturn’s Roche limit. The Roche limit tells us the distance from Saturn (or any planet) inside of which other bodies tear apart due to the planet’s gravitational force.
Put more simply, celestial bodies, like asteroids and dwarf planets, that strayed too close to Saturn, i.e. inside its Roche limit, broke apart into countless particles of ice and dust. It is these particles that form the rings.
Saturn continues to maintain its ring system because the temperature is ideal for volatile ice to exist.
Saturn is not alone in having a ring system around it. Jupiter, Neptune, and Uranus have 3, 5, and 13 rings respectively, around them as well. Our experience in this solar system is that all gas giants have rings around them.
We suspect this is because these huge bodies have a large gravitational pull, which brings other celestial bodies inside their respective Roche limits. One thing astronomers noticed about these planets is they all have pieces of ice and dust near to them while moons orbit a little far away.
This is evidence of the Roche limit at work. Inside it, bodies break up, outside it and they stay intact but captured in orbit as a moon around the planet.
When and How Did the Rings Form?
New research suggests that Saturn’s ring system is not more than 100 million years old.
One leading theory says that a huge celestial body, probably a moon, came near Saturn a long time ago. Once it crossed the Roche limit, it was torn to pieces!
This also tells us that gas giants like Saturn have a lot of gravitational pull and attract nearby bodies. Rings of Saturn and Uranus are more extensive than Jupiter and Neptune, suggesting that distance from the Sun matters too.
Rings mostly contain volatile ice, which needs cooler temperatures that the ice in your freezer to stop it from melting.
Are the Rings Still Changing?
Yes, Saturn’s rings are falling into Saturn, and will most likely disappear in the next 300 million years.
Saturn is a huge planet and exerts a tremendous amount of gravitational force. This force is felt by the residents in its ring system, which are currently being pulled into the planet’s upper atmosphere.
In fact, scientists estimate that D, the innermost ring, will disappear in the next 300 million years, which is rapid in cosmological timescales.
While other rings are still intact, they too are being affected by Saturn’s moons. Their gravity is accelerating collisions and breaking up bigger rocks into tiny pieces, thus slowly increasing the width of the rings.
How Big are the Rings of Saturn?
Saturn’s ring system spans a whopping 175,000 miles (282,000 km). Its A and B rings are the densest, thickest, and darkest, while the rest get less dense as they near Saturn.
You’ll notice that the rings are not aligned with Earth’s plane of orbit. Instead, they seem tilted because Saturn itself is tilted 27 degrees with respect to us. The ring system orbits Saturn in its equatorial plane, which is why it is also tilted 27 degrees.
As you’ll discover in our article on observing Saturn with a telescope, the angle which we can see the rings from Earth changes over time as our two planets orbit the sun. Sometimes we see the rings edge-on so that they seem to disappear, other times we see them from above or below.
The Impact of Saturn’s Moons on Rings
Saturn’s ring system also includes more than 60 moons. You’ll notice that the bigger moons’ orbits are clear; there is no debris in the path. This is called ‘clearing the neighborhood’, which is one of the conditions for it to be called a moon.
The moons also affect the dust particles and tiny rocks around them.
Collisions are common, due to which the particles’ orbits increase and change. If you look closely at the moon in the above image, you’ll notice that the area around them is wave-like, which is a change in shape caused by the moon’s gravity on the rings.
What Color Are Saturn’s Rings?
Despite the black and white images on this page, there is a lot of color in Saturn’s rings. The main shades are light pink, gray, and brown, as seen in the NASA image below.
The particles in the ring system are primarily water ice. Ice is white in color, the different color variations seen are caused by contamination of the ice with other chemicals.
When sunlight is incident on the rings, the particles reflect light differently, leading to colors. The rings are a mix of particles. Some are water ice, leftover from Saturn’s formation, while others from captured asteroids consist mainly of carbon.
Summary
Saturn is a beautiful planet, not just for the way it looks but also for the extensive ring system surrounding it. The system consists of numerous rocks, ice particles, and dust.
They were formed early in Saturn’s history from leftover material, but the rings also include captured asteroids, but scientists are still figuring out exactly how the rings formed and how they will evolve in the future.
These rings are named A through G in the order of their discovery, not their distance from the planet.
Occasionally, some moons clear their orbit and modify the rings’ shapes. Collisions within the rings tear bigger asteroids into tiny pieces, increasing the width of the rings.
That being said, Saturn’s ring system is not ever-expanding. The innermost ring is falling into Saturn’s upper atmosphere at rates that will make it disappear in the next 300 million years. The other rings are safe, for now.
This knowledge will come in handy when you aim your telescope at Saturn!
(And if you haven’t got one yet, these are great telescopes for seeing Saturn’s rings).
