The rings are the famous part. The moons are where the questions are. Where it is right now, how big and how heavy, what goes round it, and what is still unexplained.
Turning here at one rotation every 12 seconds, which is 3,168 times real speed. What is not sped up: which way it turns, how far the axis leans, and how its day compares with every other planet's. The rings are the real ring system to scale: the faint C ring from 1.24 Saturn radii, the bright B ring, the Cassini Division as a genuine gap at 1.95, then the A ring with the Encke gap near its outer edge. How far open they look is set by the real 26.7-degree tilt, which is why they close to a line twice every Saturn year. The banding is real and genuinely this faint.
Sun, August 9, 2026
——
Include:
Jump to
Distances from the sun are in AU — one AU is the Earth’s average distance, 149,597,870 km — and the angle is where the body sits around its orbit, measured from the March equinox direction.
The mass is worked out from Saturn’s gravitational parameter and the gravity from that and its radius; the year comes from Kepler’s third law and the width is the same figure the simulator draws with. None of them is typed in beside the picture, so none of them can disagree with it.
Saturn has 274 confirmed moons, of which the 9 below are large enough to be worth drawing. The rest are mostly a few kilometres of captured rubble on distant, tilted orbits. Every distance and period here is real, and they are not independent: each pair has to satisfy Kepler’s third law against Saturn’s mass, which is how this table is checked rather than trusted.
| Moon | Distance | Orbit | Width | |
|---|---|---|---|---|
| Mimas | 185,539 km | 22.6 h | 396 km | One crater a third of its own width |
| Enceladus | 237,948 km | 1.37 d | 504 km | Venting ocean water into space through cracks at its south pole |
| Tethys | 294,619 km | 1.89 d | 1,062 km | Almost pure water ice, and lighter than water |
| Dione | 377,396 km | 2.74 d | 1,123 km | Wispy cliffs of fresh ice, hundreds of metres high |
| Rhea | 527,108 km | 4.52 d | 1,528 km | Saturn’s second largest, and still only two fifths the width of our moon |
| Titan | 1,221,870 km | 15.9 d | 5,150 km | Thick nitrogen air, rain, rivers and seas — of methane |
| Hyperion | 1,481,009 km | 21.3 d | 270 km | Tumbles chaotically: it has no settled day length at all |
| Iapetus | 3,560,820 km | 79.3 d | 1,469 km | One hemisphere as dark as coal, the other as bright as snow |
| Phoebe | 12,947,780 km | 550.3 d ↺ | 213 km | Goes round backwards — captured, probably from the Kuiper belt |
↺ marks a moon going round backwards. Watch this system move →
The table above has every figure — how far out, how long a lap takes, how wide. What follows is what those figures cannot tell you: what each one is actually like, who found it and when, and what is still argued about it.
A 396 km ball of ice with a 130 km crater in it — a third of its own diameter.
That wobble means either a global ocean under 20–30 km of ice, or an elongated rocky core. In 2024 the ocean case strengthened sharply — and a young ocean under an old, cratered, unresurfaced crust is hard to explain either way.
500 km across, and it is spraying its ocean into space hard enough to build one of Saturn’s rings out of it.
How long has the ocean lasted? Some models make it only tens of millions of years old, which would be an awkward coincidence for us to be watching now.
It has water, heat, and the right chemistry. Nobody has looked for anything living in it, and a plume you can fly through is the easiest sample in the outer solar system.
Very nearly pure water ice — its density is a shade under water’s own.
The wispy streaks across it turned out not to be wisps at all.
Saturn’s second largest moon, and it has a wisp of an atmosphere made of oxygen.
The only moon with a real atmosphere — half again as thick as Earth’s at the surface — and the only other place with standing liquid on it.
Sunlight destroys atmospheric methane in about 30 million years. Something must be replacing it, and nobody knows what — cryovolcanism is the usual guess and has never been caught happening.
Its chemistry is the most complex prebiotic chemistry we can reach. Whether it goes anywhere at 94 kelvin is open.
It does not have a day. Its rotation is mathematically chaotic — there is no period to quote.
One side is as dark as coal, the other as bright as snow, and it wears a mountain range round its equator.
Nobody knows what built the equatorial ridge. A collapsed ring of its own, a seam from a re-merged body, and an upwelling have all been proposed and none is settled.
It goes round backwards, which is the giveaway: it did not form here.
Both planets are moving, so the gap between them swings enormously — and the closest approaches are not all equal, because the orbits are ellipses rather than circles. These are the next four, solved from the orbits rather than looked up.
Click a date to take the simulator there. These are minimum-distance moments, which fall near — but not exactly on — opposition.
A rocket cannot point at Saturn and fire. It has to leave Earth on an orbit around the sun whose far side touches Saturn’s orbit — half an ellipse — and it has to leave at the moment when Saturn will have arrived at that far side by the time the ship gets there. That is what a launch window is, and it is why they come round only every 12.5 months.
Set Launch to: Saturn on the rocket launches page to see the ellipse, where Saturn is on launch day, and where it will be on arrival. Click the date to fly it.
It is a minimum-energy transfer: the cheapest possible path, half an ellipse with Earth’s orbit at one end and the target’s at the other, solved against where the planets really are — so the arrival lands on the planet’s real distance from the sun and its real position on the day it gets there, not on a circle standing in for its orbit.
It is not a mission plan, and three things are left out on purpose. The orbits are treated as flat, so the real inclinations — Mars is tilted 1.85°, Jupiter 1.3° — cost a plane change this ignores. Real missions trade fuel for a faster arrival, so they leave within days or weeks of these dates rather than exactly on them. And anything going past Jupiter usually steals speed from a planet on the way instead of buying it with fuel, which changes both the date and the path.
What it gets right is the thing worth teaching: why the window exists, why it comes round on the cadence it does, and why the cost of the trip is set by where two planets happen to be rather than by how far apart they are.
Every one of these is genuinely unsettled — not simplified for the page, not waiting on a textbook update.
Cassini measured their mass and found it small, and their ice remarkably clean of the dust that constantly rains in — both of which suggest something that formed in the last 100 million years, long after the planet. Recent work argues that ring particles may shed pollution and stay looking young indefinitely, which would allow rings as old as Saturn. It is one of the sharpest open disagreements in planetary science, and it decides whether we are watching something rare and temporary or something permanent.
Sunlight destroys atmospheric methane in around 30 million years, and Titan's has not run out. Something is resupplying it — cryovolcanism, or release from clathrates in the crust — and neither has been observed happening. Dragonfly, a nuclear-powered rotorcraft due to launch in 2028 and arrive in 2034, is designed to go looking.
It has liquid water, a rocky seafloor, chemical energy, and — from a 2023 reanalysis of Cassini data — phosphates, the last of the elements considered essential for life as we know it. That is a complete list of ingredients and no evidence whatever of the thing itself. No mission is currently funded to go back.
A six-sided jet stream, 30,000 km across, has sat over Saturn's north pole for at least as long as we have been able to see it. Laboratory tanks of spinning fluid do produce polygons, so it is not magic — but why six, why so stable, and how deep it goes are not answered.
Findings reviewed August 2026. Space science moves; a date on a finding is part of the finding.
Inward: Jupiter. Outward: Uranus. Or go back to the whole system, where every planet is on screen at once.
The date, the zoom, the span, the speed, the layers and any flight path are all in the address bar, so copying the URL shares exactly what is on screen. Set it up above, then take the link — it is the quickest way to hand a class one specific thing to look at.
This one is about the whole system. If the question is where the sun and the moon are from where you are standing — what time the sun comes up, why tonight's moon is the shape it is — that is the Sun, Earth & Moon movement simulator, which has a page for every city and a slider over a day, a week or a month.
Also: the classroom guide · sunrise & sunset by city · moon phase & moonrise · lunar eclipses · how the positions are worked out
How old are the rings? Cassini measured their mass and found it small, and their ice remarkably clean of the dust that constantly rains in — both of which suggest something that formed in the last 100 million years, long after the planet. Recent work argues that ring particles may shed pollution and stay looking young indefinitely, which would allow rings as old as Saturn. It is one of the sharpest open disagreements in planetary science, and it decides whether we are watching something rare and temporary or something permanent.
Where does Titan's methane come from? Sunlight destroys atmospheric methane in around 30 million years, and Titan's has not run out. Something is resupplying it — cryovolcanism, or release from clathrates in the crust — and neither has been observed happening. Dragonfly, a nuclear-powered rotorcraft due to launch in 2028 and arrive in 2034, is designed to go looking.
Is Enceladus's ocean inhabited? It has liquid water, a rocky seafloor, chemical energy, and — from a 2023 reanalysis of Cassini data — phosphates, the last of the elements considered essential for life as we know it. That is a complete list of ingredients and no evidence whatever of the thing itself. No mission is currently funded to go back.
What makes the hexagon? A six-sided jet stream, 30,000 km across, has sat over Saturn's north pole for at least as long as we have been able to see it. Laboratory tanks of spinning fluid do produce polygons, so it is not magic — but why six, why so stable, and how deep it goes are not answered.