Saturn's Moons – Facts for Kids

Saturn's Moons – Facts for Kids
Saturn's moon Mimas [credit: Cassini mission]

Everybody recognizes Saturn's beautiful rings, but that isn't all that circles the planet. It also has some amazing moons.

Saturn has at least 82 moons, but most of them are tiny.
If you add up the mass of all Saturn's moons and rings, Titan has 96% of the total. Poor Rhea, Iapetus, Dione, Tethys, Enceladus and Mimas share less than 4%. And the other 75 plus the rings? What's left is 0.04%.

Titan could be a planet if it orbited the Sun instead of Saturn.
Titan [TYE-tun] is bigger than the planet Mercury. It's also the only moon in the Solar System with a thick atmosphere. Titan and Earth are the only Solar System bodies with nitrogen atmospheres and surface liquid. However, Titan's lakes are liquid methane, not water.

Rhea has an oxygen exosphere – that's a really, really thin atmosphere.
There was some excitement in 2010 when NASA announced that Rhea [REE-uh] had an oxygen-carbon dioxide atmosphere. But let's be clear here. Titan has an atmosphere. Rhea has an exosphere which is so thin that it's five trillion times thinner than Earth's atmosphere.

One half of Iapetus is ten times brighter than the other half.
Iapetus [ee-AP-eh-tus] looks strange. Picture a globe divided in half by a line circling the north and south poles. Each half is a hemisphere. Like our Moon, Saturn's moon Iapetus always has the same side facing the planet. That means that as it orbits, one hemisphere always leads. The leading hemisphere of Iapetus is as dark as coal. The other hemisphere is ten times brighter.

Dione is back to front.
The front side of a moon gets more craters because it runs into space rocks as the moon orbits. But the back of Dione [dye-ON-ee], which should be protected, is more heavily cratered than the front. A collision probably turned it around, but no one is sure what happened.

Tethys is made of ice.
Saturn's moons have a lot of ice in them. Tethys [TEETH-iss] is made almost completely of frozen water, and with a surface also almost all ice. That makes it very reflective. If it orbited Earth, and were where our Moon is, we'd see a body the size of the Moon but much, much brighter.

Enceladus has ice volcanoes and a hidden ocean.
Enceladus (en-SELL-uh-dus) is one of four Solar System bodies that we've seen erupting. It has many volcanoes at the south pole. These aren't the sort of volcanoes we have on Earth, shooting out hot lava. They're called cryovolcanoes which means “cold volcanoes”. They erupt liquids and vapors such as water, methane, or ammonia.

Mimas is the smallest known round body in the Solar System.
Gravity acts on matter. The amount of matter in a body is its mass. If it has enough mass, gravity pulls it into a sphere (ball). Saturn's larger moons are rounded, but the tiny ones aren't. Mimas (MY-mass) is the smallest natural body we know of that is round. Little Mimas has also been severely battered and is heavily cratered. Although its diameter is just 400 km (250 miles), it has an impact crater 140 (87 miles) across.

Some of Saturn's rings have shepherd moons.
Shepherds herd sheep and shepherd moons herd rings! Some small moons have orbits to one side of a ring and their gravitational pull helps maintain the ring shapes and the gaps between them.

Christiaan Huygens discovered Saturn's biggest moon Titan in 1655.
The European Space Agency's (ESA) Huygens probe landed on Titan on January 14, 2005. It was the first lander to set down in the outer Solar System.

Jean Dominique Cassini discovered four of Saturn's moons between 1671 and 1684.
NASA's Cassini spacecraft went into orbit around Saturn on July 1, 2004 to study Saturn, and its rings and moons. Besides its own exploration of Saturn and its system, the spacecraft also carried the Huygens probe to Saturn.

None of Saturn's moons had a name until the nineteenth century.
From the time Huygens found Titan, it took nearly two hundred years to name the moons. English astronomer John Herschel suggested names for the moons in 1847. Until then they just had Roman numerals, so Titan was Saturn I. In Greek mythology Saturn was Cronus, the ruler of the elder gods, the giants called Titans. Herschel named the largest moon Titan. He gave the other moons names of Titans. Since then, astronomers have run out of Titans and Greek myths, so they now use other mythologies for the new discoveries.



You Should Also Read:
Cassini-Huygens - the Prime Mission
Titan Facts for Kids
Saturn - Facts for Kids

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