Published: Tue, October 08, 2019
Science | By

Tech: And you can help name them!

Tech: And you can help name them!

"Studying the orbits of these moons can reveal their origins, as well as information about the conditions surrounding Saturn at the time of its formation", Sheppard said.

Saturn has broken a new solar system record with the discovery of 20 new moons circling it. The background stars and galaxies do not move, while the newly discovered Saturnian moon, highlighted with an orange bar, shows motion between the two images. Credits: Illustration is courtesy of the Carnegie Institution for Science.

Depending on when you finished school, you might have learned that Jupiter or Saturn has the most moons.

Saturn has pulled ahead of Jupiter again in the moon discovery race, thanks to a batch of 20 outer moons that bring the ringed planet's total tally to 82.

Monday's announcement came from the Minor Planet Center at the International Astronomical Union.

The moons are all similar in size, spanning about three miles across.

The more-distant retrograde moons and one of the prograde moons each take more than three years to complete an orbit. And for the Gallic-group moon ... you guessed it: a mythological Gallic giant.

"One of the more exciting things about these outer moons is that there are always missions going", Sheppard said, according to National Geographic.

All the moons in the group (the ones named already are Ijiraq, Kiviuq, Paaliaq, Siarnaq and Tarqeq) orbit at an angle to Saturn's orbit and are thought to have originally been part of a single object about 40 kilometres wide that broke into fragments.

Visit Carnegie Science's Saturn Moon Name Contest page for more contest details. But Sheppard believes that shortly after Saturn formed, more than 4bn years ago, passing asteroids and comets were captured by the planet's gravity and have circled it ever since.


One last one (in green) is an "oddball", just like Jupiter's "Valetudo".

The other newly found prograde moon has an inclination near 36 degrees, which is similar to the other known grouping of inner prograde moons around Saturn called the Gallic group.

Sheppard's team thinks that some of the newly discovered moons were once part of a larger moon that broke up. This would have cause the newly-created moons to spiral into Saturn's atmosphere and be lost.

Shortly after the Sun was born of the nebula's gas and dust, the remaining material fell into a disk that gradually accreted to form the planets. The gas giant was surrounded by a disk of dust and gas as it was taking shape.

"Using some of the largest telescopes in the world, we are now completing the inventory of small moons around the giant planets", Scott Sheppard, a Carnegie astronomer who led the discovery team, said in a press release.

In addition to Sheppard, the observing team included UCLA's David Jewitt and the University of Hawaii's Jan Kleyna.

Two discovery images for the "oddball" prograde moon of Saturn, taken about one hour apart, using the Subaru telescope.

By studying these small moons and their interactions with our solar system's large planets, astronomers can answer questions about how these worlds were formed and how they've evolved.

It's harder spotting mini moons around Saturn than Jupiter, Sheppard added, given how much farther away Saturn is.

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