Epimetheus (moon) facts for kids

This picture of Epimetheus was taken by the Cassini-Huygens spacecraft.

Epimetheus is a small moon that orbits the planet Saturn. It's one of Saturn's many moons. Epimetheus is special because it shares its orbit with another moon called Janus. They have a very unique and interesting way of moving around Saturn!

Discovering Epimetheus

Scientists first saw Epimetheus in 1966. A person named Richard Walker found it. At first, they thought it might be the same moon as Janus. This was because both moons orbit Saturn at almost the same distance. It was hard to tell them apart!

But later, in 1980, a spacecraft called Voyager 1 flew by Saturn. It confirmed that Epimetheus and Janus were actually two separate moons. This was an exciting discovery!

A Unique Orbital Dance

Epimetheus and Janus are known as "co-orbital" moons. This means they orbit Saturn at almost the same distance. They are very close to each other.

Every four years, these two moons get very close. When they do, they swap places! The moon that was slightly closer to Saturn moves a bit farther away. And the moon that was slightly farther away moves a bit closer. They trade orbits without ever crashing into each other. It's like a cosmic dance!

This special orbital swap happens because of their gravity. As they approach each other, their gravitational pull causes them to exchange energy. This makes them switch their paths around Saturn.

What Epimetheus Looks Like

Epimetheus is not very big. It has an irregular shape, meaning it's not perfectly round like Earth's moon. It's covered in many craters. These craters were made by space rocks hitting its surface over billions of years.

Scientists have used spacecraft like Voyager 1 and Cassini to study Epimetheus. These missions have sent back amazing pictures. They help us learn more about this small, unique moon of Saturn.

Images for kids

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  Epimetheus (lower left) and Janus (right) seen on March 20, 2006. They appear close because of foreshortening. In reality, Janus is about 40,000 kilometers farther from Cassini than Epimetheus.

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  This picture shows the special "horseshoe orbits" of Janus and Epimetheus.

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  An animation showing Epimetheus's orbit.       Saturn ·       Janus  ·       Epimetheus

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  Epimetheus with the shadow of Saturn's F Ring across it. This image was taken by Voyager 1.

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  Epimetheus during a close flyby on December 6, 2015.

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  A mosaic of five images taken during a February 2017 flyby.

See also

In Spanish: Epimeteo (satélite) para niños