Astronomy Astronomers find new moon of Uranus
Astronomers have discovered a new moon of the planet Uranus with the James Webb Space Telescope. The celestial body with the provisional designation S/2025 U1 extends the number of Uranus moons known to date to 29, according to the US space agency NASA.
20.08.2025, 13:38
20.08.2025, 13:39
SDA
The satellite became visible in a series of ten long exposures, each 40 minutes long, with the near-infrared camera (NIRCam) of the Webb telescope. The data was analyzed by a research group at the Southwest Research Institute (SwRI) in the US state of Colorado. The team led by Maryame El Moutamid estimates the diameter of the celestial body to be around ten kilometers. "It's a small moon, but a significant discovery - even Voyager 2 didn't see it when it passed by almost 40 years ago," said El Moutamid.
Mini moon with great significance
This makes S/2025 U1 smaller and fainter than all previously known inner moons of Uranus. Due to its low brightness, it remained hidden from earlier observations, for example by the "Voyager 2" space probe launched in 1977 and other telescopes.
Seen from the sun, the ice giant Uranus is the seventh planet in the solar system. With a diameter of a good 51,000 kilometers, it is the third largest planet. The newly discovered moon moves in an almost circular orbit at a distance of around 56,000 kilometers from the planet's center, between the orbits of the moons Ophelia and Bianca.
"No other planet has as many small inner moons as Uranus, and their interactions with the rings suggest a chaotic history," explained team member Matthew Tiscareno.
Moons have so far been named after literary characters
So far, all of Uranus' moons have been named after characters from the two English poets William Shakespeare and Alexander Pope. The official name of S/2025 U1 will be decided by the International Astronomical Union - although the process may take some time.
For the scientists, the discovery shows just how much the James Webb Space Telescope is advancing research into the outer planets of the solar system. "Almost four decades after Voyager 2, the James Webb telescope is expanding our view of Uranus and its enigmatic lunar system," says El Moutamid.
