Saturn for Kids: Rings, Moons and the Hexagon Storm
Saturn's rings are 280,000 kilometres across and, in most places, about ten metres thick. Scaled to a sheet of paper the size of a football pitch, the paper would be too thick. That one comparison does more for a child than any photograph, because photographs make the rings look solid, and they are not: they are a blizzard of ice, every chunk on its own orbit, that you could fly a spacecraft through and, from inside, barely see.
Everything below comes from the 3Eyes Saturn lesson - a 3D interactive where a child flies through the rings, circles the hexagon storm and stands on six of the moons with the planet in the sky. The recordings below are taken straight from it; the lesson itself is part of 3Eyes.
The rings are ice, and mostly empty
Almost everything in the rings is water ice - around 99 per cent, which is why they are so bright. The pieces range from dust grains to boulders the size of a house, and most are somewhere around the size of a snowball. They are not attached to each other. Each one is a tiny moon going round Saturn on its own, the inner ones faster than the outer, occasionally bumping and sticking and breaking apart again.
Seen from Earth the rings look like a few broad bands with gaps. Up close they are thousands of ringlets, and the gaps - the Cassini Division is the big one - are swept clear by the gravity of small moons whose orbits resonate with them. Fly into the ring plane, as the lesson does, and the whole thing flattens into a line: a field of tumbling ice stretching to the horizon, and nothing above or below it.
The hexagon at the north pole
At Saturn's north pole there is a storm with six straight sides. It is about 30,000 km across - wide enough to fit two Earths - and it has been there since at least 1981, when Voyager first photographed it. A hurricane sits in the middle, with an eye fifty times bigger than any on Earth, and the six-sided wall of wind rotates around it at more than 300 km/h.
Nothing else in the solar system looks like it. The best explanation is that a fast jet stream circling the pole is flapping in a standing wave with six crests, the way a flag ripples in a steady wind, and the ripples have locked into place. Scientists have made hexagons in a spinning tank of water in a lab. It remains one of the strangest things you can point at, and it is the reason the lesson has a "hexagon storm" stop.
The moons are where it gets interesting
Saturn has 146 known moons and counting. Six carry the story.
| Moon | Size | What it is famous for |
|---|---|---|
| Titan | 5,150 km - bigger than Mercury | The only moon with a thick atmosphere; lakes of liquid methane |
| Enceladus | 500 km | Jets of water erupting from an ocean under the ice |
| Mimas | 400 km | A crater so big it looks like the Death Star |
| Rhea | 1,530 km | Ice and rock, heavily cratered, possibly its own faint ring |
| Iapetus | 1,470 km | One side black as coal, the other white as snow |
| Dione | 1,120 km | Bright ice cliffs hundreds of metres high |
Titan is the one to know. It is wrapped in an orange haze so thick that no telescope can see the ground; the Huygens probe parachuted through it in 2005 and landed on damp, pebbly ground beside what looked like a dried riverbed. It rains there - not water, but methane, which at −179 °C is a liquid - and there are rivers, lakes and seas of it. Standing on the surface, as the lesson lets you, the sky is a dim orange and Saturn hangs in it as a pale disc. NASA's Dragonfly drone is on its way there, due to arrive in 2034.
Enceladus is tiny, bright white, and leaks. Cracks near its south pole - the tiger stripes - spray plumes of water hundreds of kilometres into space, fed by a salty ocean under the ice crust. Cassini flew through the plumes and tasted salt, organic molecules and hydrogen, which is food for microbes. Of everywhere we know of beyond Earth, this small moon is one of the two or three best places to look for life.
Saturn itself, in six numbers
- Nine Earths across. It is the second-largest planet.
- A day is 10.7 hours. It spins so fast it bulges visibly at the equator.
- A year is 29.4 Earth years. A child born today will see one Saturn birthday at 29.
- Less dense than water. Saturn is mostly hydrogen and helium; given a large enough bath, it would float.
- Winds of 1,800 km/h near the equator, four times the strongest ever recorded on Earth.
- The rings are young - possibly only 100 million years old, which means the dinosaurs may have seen a Saturn without them. They are also slowly raining into the planet and may be gone in another 100 million.
How to explain it in five minutes
Start with the sheet of paper. Rings the size of a football pitch, thinner than paper. Then say they are made of separate snowballs. Both facts are hard to believe and both are true.
Fly into them. The lesson's "inside the rings" view is the moment the rings stop being a picture - tumbling ice, a flat plane, nothing overhead.
Then the hexagon. Ask why a storm might have straight sides. There is no tidy answer, and a child should hear that scientists are still arguing.
Finish on Titan. Rain that is not water, a sky that is orange, and a drone on its way. It is the best "somewhere else" in the solar system.
Where 3Eyes Fits
The Saturn lesson above is one of about sixty interactive science lessons built into 3Eyes, which is a parental controls product for family computers - it filters the machine, approves sites rather than blocking them one at a time, and limits YouTube to channels you choose.
The lessons exist because a restriction with nothing behind it is a hard argument to win. A laptop with sixty science lessons and a tutor on it makes the limits part of something rather than the whole of it.
About two minutes to set up. See what it includes or create an account.
Frequently asked questions
What are Saturn's rings made of? Almost entirely water ice - about 99 per cent - in pieces from dust grains to house-sized boulders, each orbiting the planet separately. A little rock dust darkens them in places. They are not solid and never were.
How thick are Saturn's rings? Mostly around 10 metres, and rarely more than a kilometre, across a span of 280,000 km. Proportionally they are far thinner than a sheet of paper, which is why they vanish when seen edge-on from Earth every fifteen years.
What is the hexagon on Saturn? A six-sided jet stream around the north pole, about 30,000 km across, with a hurricane in the middle. It is thought to be a standing wave in the wind that has locked into a six-crest pattern. It has been there since at least 1981.
Could there be life on Saturn's moons? Possibly - Enceladus has a salty underground ocean venting water, organic molecules and hydrogen into space, and Titan has a chemistry-rich surface and an ocean of its own beneath the ice. Both are top targets; neither has shown life yet.
How many moons does Saturn have? 146 confirmed as of 2023, the most of any planet, and the count keeps rising as small ones are found. Only seven are large enough to be round; Titan alone holds more than 95 per cent of the mass of all of them.