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Saturn Surpasses Jupiter as Planet with Most Moons

FILE - This image provided by NASA captures the transit of several moons across the face of Saturn. The giant orange moon Titan – larger than the planet Mercury – can be seen at upper right.

Researchers say Saturn has overtaken Jupiter as the planet in our solar system with the most number of moons.

U.S. scientists announced Monday that 20 new moons have been found orbiting Saturn, bringing the total number of moons around that planet to 82. That beats Jupiter's 79 moons.

Researchers say the new moons were not previously known because they are so small in size. They say the moons are barely 5 kilometers in diameter and have only been discovered now because of advances in technology that include better telescopes and computing power.

The scientists who made the discovery, led by Scott Sheppard at the Carnegie Institute of Science in Washington, used the powerful Subaru telescope in Hawaii to gather data over several years, as well as new computing algorithms, to track potential moons and orbits.

Sheppard said the discovery of the moons can help scientists learn how planets in our solar system were formed.

"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 in a release from Carnegie on Monday.

Sheppard's team thinks that some of the newly discovered moons were once part of a larger moon that broke up.

Seventeen of the moons have a retrograde orbit, meaning they orbit in the opposite direction as Saturn and its other moons. All of the newly discovered moons take between two and three years to travel once around Saturn.

FILE - The planet Jupiter is shown with one of its moons, Ganymede (bottom), in this NASA handout taken April 9, 2007.
FILE - The planet Jupiter is shown with one of its moons, Ganymede (bottom), in this NASA handout taken April 9, 2007.

Sheppard says there are likely more moons to be found around Saturn that are even smaller than the latest discoveries, but says astronomers will need larger telescopes to find them.

While the ringed planet has bested Jupiter in the number of moons, Jupiter still has the edge on another moon statistic — the biggest moon. Jupiter's Ganymede moon is more than 5,268 kilometers in diameter, almost half the size of Earth.

Carnegie set up a contest to name the newly discovered moons, with the new names based on Inuit, Norse and Gallic mythology. The contest opened Monday and will last for two months.