Saturn, the giant planet known for its rings, is now being celebrated for having the highest number of moons in the solar system – 145 total, after gaining 62 additional moons in May, according to extensive astronomer calculations. That’s more “traditional moons” than the other planets combined.
The new moons, which the International Astronomical Union will announce later this month, put Saturn ahead of Jupiter, which has 95 moons.
Besides increasing our knowledge of the solar system, “these many new moons around Saturn demonstrate that science continuously progresses as telescopes and instruments get more sensitive,” Lars Christensen, director of communications at the Astronomical Union, told USA TODAY.
Saturn is the sixth planet in the solar system and is about 910 million miles from the sun. It’s the second-largest planet and is approximately 10 times larger than Earth. Its moons “are on the limit of what’s visible today,” Christensen says.
“We now know that our solar system – and most likely other planetary systems out in the universe – are a continuous distribution of objects, from dust over kilometer-sized moons to asteroids, comets and planets,” he says.
How does Saturn rank in number of moons?
Counting Saturn’s new moons, there are 289 moons among the eight planets in the solar system and Pluto, which has five. Pluto was reclassified as a dwarf planet from a full-size one by the International Astronomical Union in August 2006.
Saturn’s first moon discovered 368 years ago
Titan – almost as large as Mars – was the first of Saturn’s moons to be discovered. Dutch astronomer Christiaan Huygens found it using a telescope in March 1655.
How were Saturn’s new moons discovered?
Astronomers sifted through years of data with a process called “shift and stack” to detect Saturn’s smaller moons.
The technique uses a series of photographs taken with a space telescope. Astronomers used images from the Canada-France-Hawaii Telescope on top of Mauna Kea, Hawaii. Images were taken over many three-hour periods between 2019 and 2021.
The images were shifted, or aligned, to match the potential orbital paths of moons. Then the images were stacked, or merged, in a way that combined and highlighted the moons’ faint light.
The enhanced light from shifting and stacking can reveal the paths of moving objects, such as moons, planets, or asteroids. While the technique has found moons around Uranus and Neptune, it’s the first time it was used for Saturn.
How large are Saturn’s new moons?
Most of the 62 newly confirmed moons are relatively small in size. (About half of all Saturn moons are less than two miles in diameter.) The new moons orbit Saturn at distances between 6 million and 18 million miles.
Most of Saturn’s moons are ‘irregular’
More than 80% of Saturn’s moons are classified as irregular moons, described as moons with atypical orbits. Most moons of the outer planets – Jupiter, Saturn, Uranus and Neptune – are considered irregular.
How moons differ:
Regular moon
- Prograde orbit: The moon orbits the planet in the same direction the planet rotates.
- The moon orbits on the equatorial plane of the planet.
- The moon was probably formed at the same time as the planet’s creation.
Irregular moon
- Retrograde orbit: The moon orbits the planet in the opposite direction of the planet’s rotation.
- The moon orbits the planet on an inclined, or different plane.
- Moon orbits are often more elliptical.
- The moon was probably captured by the planet’s gravitational field.
“The universe does not like to be put in boxes,” Christensen says. “Some of the moons may be captured asteroids and vice versa.”
Are more moons out there?
“Surely more smaller moons exist around Saturn, but it will get harder and harder to keep track of them,” Christensen says.
“Despite being almost 5 billion years old, the solar system still remains a bit of a construction site with many interesting small objects in its inventory,” he says.
Two groups discovered Saturn’s new moons. An international team of astronomers who confirmed the moons was led by Edward Ashton of Taiwan’s Academia Sinica Institute of Astronomy and Astrophysics in 2019-21 and includes:
Another team led by Scott Sheppard, of the Carnegie Institution for Science in Washington, D.C., used the Subaru Telescope in Hawaii to search for Saturn moons in the mid-2000s. Some of his findings were verified by Ashton’s team.
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SOURCE USA TODAY Network reporting and research; Associated Press; NASA; Jet Propulsion Laboratory; International Astronomical Union; space.com; University of British Columbia; scitechdaily.com
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