Scientists have discovered three new moons in the solar system, including two around Neptune and the smallest moon of Uranus found in over 20 years.
“The three newly discovered moons are the faintest ever found around these two ice giant planets using ground-based telescopes,” said Scott S. Sheppard at the Carnegie Institution for Science, who used the Magellan telescopes at Carnegie Science’s Las Campanas Observatory in Chile. “It took special image processing to reveal such faint objects,” he said. The discoveries required taking dozens of five-minute exposures over several hours.
Here’s what Sheppard found:
- S/2023 U1, 8 kilometers in size, which takes 680 days to orbit Uranus.
- S/2002 N5, 23 kilometers in size, which takes almost 9 years to orbit Neptune.
- S/2021 N1, 14 kilometers, which takes almost 27 years to orbit Neptune.
New Moon At Uranus
First spotted on November 4, Sheppard also found the tiny moon S/2023 U1 in images he’s taken in 2021 using the Magellan telescope and the Subaru telescope in Hawaii. Its discovery brings the ice giant planet’s total moon count to 28.
The six largest moons around the seventh planet from the sun are Ariel, Umbriel, Titania, Oberon, Puck, and Miranda, the first four of which are suspected to host underground oceans. A proposed Uranus orbiter on a NASA flagship mission would likely concentrate on finding out if those moons may be ocean worlds.
As with its existing moons, S/2023 U1 will eventually be named after characters from the works of William Shakespeare and Alexander Pope. However, Uranus is the only planet in the solar system named after the Greek god of the sky (the father of Saturn and the grandfather of Jupiter).
Neptune’s Nymphs
Neptune—which was recently revealed not to be as blue as first thought—now has 16 moons, the most famous of which is Triton. It’s thought to be an ocean world and is among the most promising places in the entire solar system to look for signs of life.
As with Neptune’s existing moons—which also include Naiad, Thalassa, Despina, Galatea and Proteus—its two newly discovered moons will be named after the Nereid sea nymphs in Greek mythology.
Moon Inventory
It’s much harder for planetary astronomers to complete an inventory of moons at outer planets Neptune and Uranus than at planets closer to Earth. All moons of about 2 kilometers in size have been found at Jupiter, while at Saturn it’s 3 kilometers. However, for Uranus and Neptune, it’s between 8 and 14 kilometers, respectively. That’s partly because Jupiter and Saturn have been visited multiple times by spacecraft, while Uranus and Neptune have only been visited once by NASA’s Voyager 2 probe in 1986 and 1989, respectively.
However, a rare planetary alignment in the 2030s may provide a window to visit Uranus and Neptune after a slingshot around Jupiter—though any spacecraft would need to leave Earth by the early 2030s to get to Uranus by the 2040s.
Wishing you clear skies and wide eyes.