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Saturn Becomes ‘Moon King’ with 20 New Discoveries

2019-10-13

The planet Saturn is being recognized as the “moon king” of our solar system.

Jupiter used to hold the record for most moons orbiting around it. It has 79. But scientists in the United States have announced the discovery of 20 new moons around Saturn. That gives the planet a new total of 82 moons.

The researchers made the discovery using the powerful Subaru telescope in Hawaii. They gathered information over a period of several years.

The team also used new computing models to identify moons and follow orbiting activity.

Scott Sheppard led the research team. He is with the Carnegie Institution for Science in Washington, D.C. “Saturn is the moon king,” Sheppard told Reuters news agency.

The discovery was announced last week by the International Astronomical Union’s Minor Planet Center. The center is responsible for identifying all the world’s minor planets, comets and “outer natural satellites.” The organization also measures the orbital movements of such objects.

Titan, in front of Saturn, as seen by Cassini
Titan, in front of Saturn, as seen by Cassini

Researchers say the newly found moons are very small, measuring about five kilometers across. The team was able to discover them now because of better technology that became available in recent years. This includes more powerful telescopes and increased computing power.

Saturn is a gas planet made up mostly of hydrogen and helium. It is the second-largest planet in the solar system and the sixth from the sun. It measures about 116,000 kilometers across.

One of the newly identified moons orbits Saturn from a huge distance away, about 25 million kilometers from the planet. This is farther away than any of Saturn’s other moons. By comparison, Earth’s moon orbits about 386,000 kilometers from the planet.

Seventeen of the moons orbit Saturn backwards. In other words, their movement is opposite of the planet's rotation. The other three orbit in the same direction as the planet rotates.

The researchers said a number of the moons appear to have been formed from parts of larger moons. Those past moons likely broke up in crashes with other moons or with comets or asteroids. This is similar to how some of Jupiter’s 79 moons were formed.

Sheppard said scientists can learn many new things from Saturn’s moons.

“These new moons show us the solar system was a very chaotic place in the distant past, with objects flying all over the place,” Sheppard said. He added that the moons are among the last pieces of evidence left over from the formation of the solar system. All other objects were either pushed out or became parts of other planets.

Sheppard hopes the discovery can help scientists keep learning more about how planets in our solar system came to be.

"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," he said.

Sheppard added that there are likely more moons around Saturn that are even smaller than the latest discoveries. But he says astronomers will need larger telescopes to find them.

The Carnegie Institution for Science is asking the public for help to name the newly discovered moons.

I’m Bryan Lynn.

Bryan Lynn wrote this story for VOA Learning English, based on reports from The Associated Press, Reuters and VOA News. Ashley Thompson was the editor.

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Words in This Story

rotate n. to turn in a circular direction

asteroid n. a rocky object that goes around the sun like a planet

chaotic adj. in a state of disorder

reveal v. to give someone a piece of information that is surprising or that was previously secret

origin n. the cause of something, or where something begins or comes from