Moons of Saturn facts for kids

The moons of Saturn are a fascinating family of natural satellites that orbit the giant planet Saturn. Saturn has more confirmed moons than any other planet in our Solar System, with 146 known moons! This huge number doesn't even count the thousands of tiny "moonlets" found within Saturn's famous rings.

Some of Saturn's moons are very small, only a few meters across. But one moon, Titan, is enormous! It's even bigger than the planet Mercury. Seven of Saturn's moons are large enough to be round, like Earth's Moon.

Three moons are especially interesting:

• Titan is the second-largest moon in our Solar System (after Jupiter's Ganymede). It has a thick atmosphere, much like Earth's, and even has rivers and lakes made of liquid methane!
• Enceladus shoots out amazing jets of ice from its south pole. It's covered in a deep layer of snow.
• Iapetus is unique because one side is super dark, and the other side is bright white. It also has a huge mountain ridge around its middle, like a giant seam.

Saturn's moons are divided into two main types:

• Regular moons orbit Saturn in a fairly flat path, close to the planet's equator. Most of these moons orbit in the same direction as Saturn spins.
• Irregular moons orbit much farther away. They have tilted and stretched-out orbits, and many even orbit in the opposite direction to Saturn's spin. Scientists think these irregular moons were probably captured by Saturn's gravity a long time ago.

The rings of Saturn are also made of countless small objects, from tiny dust grains to moonlets hundreds of meters wide. Because of this, it's hard to say exactly how many "moons" Saturn has, as there's no clear line between a tiny ring particle and a small moon.

Discovering Saturn's Moons

People have been looking at Saturn and its moons for a long time!

First Discoveries with Telescopes

Before cameras were invented for telescopes, astronomers found eight of Saturn's moons just by looking through their telescopes.

• In 1655, Christiaan Huygens discovered Saturn's largest moon, Titan. He used a telescope he designed himself.
• Between 1671 and 1684, Giovanni Domenico Cassini found four more moons: Tethys, Dione, Rhea, and Iapetus.
• In 1789, William Herschel discovered Mimas and Enceladus.
• In 1848, Hyperion was found by a team of astronomers.

Later, using special long-exposure photography, more moons were found.

• Phoebe was the first moon discovered this way in 1899 by W. H. Pickering.
• In 1966, the tenth moon, Janus, was discovered. A few years later, scientists realized another moon, Epimetheus, shares almost the exact same orbit as Janus! They swap places every four years instead of crashing.
• In 1980, three more moons were found from Earth and later confirmed by space probes. These were Helene, Telesto, and Calypso. These moons are called "Trojan moons" because they orbit in special spots near larger moons.

Discoveries by Spacecraft

Space probes have completely changed how we study planets far away.

• The Voyager spacecraft visited Saturn in 1980–1981. They found three new moons: Atlas, Prometheus, and Pandora. This brought the total to 17 moons at the time.
• In 1990, Pan was found in old Voyager pictures.
• The Cassini mission arrived at Saturn in 2004. It discovered three small inner moons: Methone, Pallene, and Polydeuces.
• Cassini also found many tiny moonlets inside Saturn's rings, which create propeller-shaped gaps. One of these, Daphnis, was seen directly.
• In 2007, Anthe was announced.
• In 2009, Aegaeon was found inside Saturn's G Ring. Also, the first moonlet inside the B Ring, S/2009 S 1, was seen.
• In 2014, scientists even saw what might be the very beginning of a new moon forming within the A Ring!

Finding Moons Far Away

New telescope technology has helped find even more moons.

• In 2000, over 30 new irregular moons were discovered using telescopes on Earth. These moons orbit very far from Saturn in stretched-out and tilted paths. They are likely pieces of larger space rocks that Saturn's gravity captured.
• In 2005 and 2006, more small outer moons were found.
• In 2019, 20 new irregular moons were reported. This meant Saturn had more known moons than Jupiter for the first time since 2000!
• In 2023, an amazing 62 more moons were announced! This brought Saturn's total to 145 confirmed moons, making it the first planet known to have over 100 moons. Another moon, S/2006 S 20, was announced shortly after, bringing the total to 146.
• These new moons are small and faint. Scientists think they are likely fragments from a collision that happened millions of years ago.

Naming Saturn's Moons

The names for Saturn's moons come from old stories and myths.

• In 1847, John Herschel suggested naming them after characters connected to the Roman god Saturn (who was like the Greek god Cronus).
• The first seven moons were named after Titans, Titanesses, and Giants, who were brothers and sisters of Cronus.
• When all the Titan names were used up, new moons were named after other characters from Greek and Roman myths, or giants from other mythologies.
• Most of the irregular moons (except Phoebe) are named after gods from Inuit, Gallic, and Norse stories.

Sometimes, asteroids have the same names as Saturn's moons, like 55 Pandora and 106 Dione.

What Saturn's Moons Are Like

Saturn's moon system is very uneven. One moon, Titan, makes up more than 96% of all the mass orbiting Saturn! The other six large, round moons make up about 4% of the mass. All the other small moons and the rings together make up only a tiny fraction.

Groups of Moons

Saturn's moons can be put into different groups based on how they orbit.

Inner Moons

These moons orbit close to Saturn, often within its ring system.

Ring Moonlets

These are tiny moons found inside Saturn's rings.

• In 2009, a moonlet called S/2009 S 1 was found in the B Ring. It's only about 300 meters (less than a third of a mile) wide.
• Many tiny moonlets have been found in the A Ring. They are too small to see directly, but they create "propeller" shapes in the ring material. These moonlets are usually between 40 and 500 meters (130 to 1,600 feet) across.
• Scientists think there might be thousands of these "propellers" in the A Ring.

Ring Shepherds

Shepherd moon Daphnis in the Keeler gap

Shepherd moons are small moons that orbit near or within a planet's rings. They help keep the rings in shape, creating sharp edges and gaps.

• Saturn's shepherd moons include Pan (in the Encke gap), Daphnis (in the Keeler gap), and Prometheus (near the F Ring).
• Janus and Epimetheus are special co-orbital moons. They are similar in size and share almost the same orbit. Instead of colliding, they swap orbits every four years!

Other Inner Moons

Other inner moons that are not ring shepherds or moonlets include Atlas and Pandora.

Inner Large Moons

These are the bigger moons that orbit inside or near Saturn's faint E Ring.

• Mimas is the smallest of Saturn's inner round moons. It has a giant impact crater called Herschel, which makes it look a bit like the Death Star from Star Wars! Mimas has a water ocean deep under its surface.
• Enceladus is one of the smallest spherical moons, but it's very active! Its surface has old, cratered areas and younger, smooth areas. Near its south pole, there are warm cracks called "tiger stripes" that shoot out jets of water vapor and dust. These jets help create Saturn's E ring. Enceladus is one of the brightest objects in the Solar System because it's covered in pure ice.
• Tethys is the third-largest inner moon. It has a huge crater named Odysseus and a massive canyon system called Ithaca Chasma. Tethys is mostly made of water ice.
• Dione is the second-largest inner moon. Most of its surface is old and cratered, but it also has a network of cracks and lines, showing it had a lot of geological activity in the past. Dione might still be slightly active today.

Alkyonides Moons

Three tiny moons orbit between Mimas and Enceladus: Methone, Anthe, and Pallene. They are some of the smallest moons in Saturn's system. Methone looks like an egg and has very few craters.

Trojan Moons

Trojan moons are special because they orbit in front of or behind a much larger moon, staying in a stable spot.

• Tethys has two Trojan moons: Telesto (leading) and Calypso (trailing).
• Dione also has two: Helene (leading) and Polydeuces (trailing).

These moons are covered in a dusty material that makes their surfaces smooth.

Outer Large Moons

These moons orbit farther out from Saturn, beyond the E Ring.

• Rhea is the second-largest of Saturn's moons. It has a heavily cratered surface, with some large fractures. Scientists once thought Rhea might have its own faint rings, but later observations didn't confirm them.
• Titan is Saturn's biggest moon and the second-largest in the Solar System. It has a thick, cold atmosphere made mostly of nitrogen, like Earth's. Titan has clouds and a hazy sky. Its surface has dark and light areas, river channels, and possibly ice volcanoes. It's the only place in the Solar System besides Earth with liquid bodies on its surface – lakes of methane and ethane! Scientists also believe Titan has a hidden ocean of water mixed with ammonia under its surface.
• Hyperion is Titan's closest neighbor. It has a very irregular, sponge-like shape and a tan-colored icy surface. Hyperion is unique because it has a chaotic rotation, meaning it tumbles unpredictably through space!
• Iapetus is the third-largest moon and orbits very far from Saturn. It's famous for its two-toned surface: one side is super dark, and the other is bright white. Cassini images also showed a 20-kilometer (12-mile) tall ridge around its equator, like a giant mountain range! Scientists think the dark material comes from dust kicked up from another moon, Phoebe, which then gets trapped on Iapetus's leading side.

Irregular Moons

Irregular moons are small satellites that orbit very far from Saturn. They have large, tilted, and often backward (retrograde) orbits. Scientists believe they were captured by Saturn's gravity. These moons are usually dark and have surfaces made of water ice, carbon dioxide, and other materials.

Inuit Group

This group includes 13 moons that orbit in the same direction as Saturn (prograde). They are similar in distance and color. The largest is Siarnaq, about 39 km (24 miles) wide.

Gallic Group

This group has seven prograde moons, also similar in distance and color. The largest is Albiorix, about 29 km (18 miles) wide.

Norse Group

This is the largest group, with 100 moons that orbit backward (retrograde) compared to Saturn's spin.

• Phoebe is by far the largest irregular moon, about 213 km (132 miles) wide. It has a dark, heavily cratered surface. Scientists think Phoebe might be a captured object from the outer Solar System, beyond Neptune. Phoebe is also the source of material for Saturn's largest known ring, which is very faint and darkens one side of Iapetus.
• After Phoebe, Ymir is the largest known retrograde irregular moon, but it's only about 22 km (14 miles) wide.

How Saturn's Moons Formed

Scientists believe that Saturn's system of large moons and rings developed from a setup that might have been similar to Jupiter's large moons. One idea is that a second moon, as big as Titan, broke apart, creating the rings and the inner moons. Another idea is that two large moons crashed together to form Titan, and the icy pieces from that crash formed the mid-sized moons.

Some studies suggest that the inner moons, up to Rhea, might be relatively young, only about 100 million years old.

Images for kids

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  Five moons in a Cassini image: Rhea bisected in the far-right foreground, Mimas behind it, bright Enceladus above and beyond the rings, Pandora eclipsed by the F Ring, and Janus off to the left

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  Quadruple Saturn–moon transit captured by the Hubble Space Telescope

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  Possible beginning of a new moon of Saturn imaged on 15 April 2014

In Spanish: Satélites de Saturno para niños