05/27/2026
Did you know that sharks have lived on Earth longer than Saturn has had rings? The earliest shark ancestors first appeared on Earth about 450 million years ago in the Ordovician period, but it took another ~50 million years for shark-like fishes to become common, and “modern” sharks didn’t appear until about 200 million years ago in the Triassic period. Saturn’s rings, on the other hand, are believed to be at least a little bit younger.
⭐ What are “rings” on a planet?
Planetary rings are disks or toruses (a 3D donut-like shape) that orbit a planet. These disks of material contain dust, rocky debris, and chunks of ice that range in size from tiny microscopic particles to massive house-sized boulders. Typically, rings form when a comet, asteroid, or small moon gets a little too close to the planet and is torn apart by the planet’s gravitational forces or collides with other small bodies. Eventually, the debris spreads out and flattens into a disc shape by the planet’s gravity and rotation. Four planets in our solar system have ring systems – Saturn, Jupiter, Uranus, and Neptune – but ring systems are theorized to exist with planets outside of our solar system as well, such as planet J1407b that has a ring system about 200 times larger than Saturn’s!
⭐ What are Saturn’s rings?
Saturn’s rings are thought to be composed of pieces of comets, asteroids, or small moons that were broken up by Saturn’s powerful gravity before they even reached the planet. As with other ring systems, the particles range in size from dust grains to the occasional piece as large as a mountain! Saturn’s rings are only about 30 feet thick on average, but they extend as far as 175,000 miles from the planet. The rings are named alphabetically in the order they were discovered, but are not in alphabetical order physically. Starting at Saturn and moving out, the rings are named D ring, C ring, B ring, A ring, F ring, G ring, and E ring. Though most of the rings are very close together, there is a large gap between rings A and B, called the Cassini Division, that measures 2,920 miles wide.
⭐ Where did Saturn’s rings come from?
Though scientists have been studying Saturn’s rings for decades, we still don’t know exactly where they came from. New research suggests that the rings could have formed from the debris of two small icy moons that collided and shattered a few hundred million years ago, which may have also led to the formation of some of Saturn’s current icy moons. Fun fact: as of the last official count, Saturn has 274 moons!
⭐ How old are Saturn’s rings?
Scientists have been studying data from NASA’s Cassini mission, which spent over 14 years orbiting Saturn and collecting data, to see if there might be a clue as to how old Saturn’s rings are. One thing the scientists have determined is that the rings are almost entirely pure ice, without much “pollution” of dust particles from micrometeoroids. This, and other evidence, suggests that the icy ring material can’t have been exposed for more than a few hundred million years. Additionally, further research suggests that Saturn’s rings could have reached their current mass in just a few hundred million years as well. Based on all of this evidence, researchers believe that Saturn’s rings are not more than 400 million years old. Interestingly, one thing the Cassini mission discovered is that the rings are losing mass quickly, so scientists believe Saturn may lose its rings in the next few hundred million years.
As with all things in science, our understanding develops as more evidence is gathered. Research is still ongoing regarding the origin and age of Saturn’s rings, and though the leading theory is that Saturn’s rings are much younger than the planet itself, there are those who argue that the rings formed around the time of the planet’s formation, about 4.5 billion years ago.
So, are Saturn’s rings younger than sharks? Maybe. Probably. Possibly. We don’t know for sure at this point. But given the evidence we’ve seen so far, it’s fair to say that sharks have been alive longer than Saturn has had rings!
📷: Saturn and its rings, taken by Cassini. Via NASA/JPL-CalTech
