NASA’s James Webb Space Telescope has discovered a new tiny moon orbiting Uranus. The moon, designated S/2025 U1, is about 6 miles (10 kilometers) in diameter and was spotted by the telescope’s Near-Infrared Camera (NIRCam) during observations in February. The discovery increases the total number of known Uranian moons to 29.
A team led by scientists at the Southwest Research Institute (SwRI) in Colorado made the discovery using ten different 40-minute exposures from JWST. The newly discovered moon orbits Uranus at a distance of about 35,000 miles (56,000 km) from the planet’s center, alongside other small satellites situated inside the orbits of the planet’s largest moons. Its circular path suggests it likely formed in its current position.
Tiny new moon discovered by JWST
“No other planet has as many small inner moons as Uranus, and their complex interrelationships with the rings hint at a chaotic history that blurs the boundary between a ring system and a system of moons,” said Matthew Tiscareno of the SETI Institute in Mountain View, California. “The new moon is smaller and much fainter than the smallest of the previously known inner moons, making it likely that even more complexity remains to be discovered.”
S/2025 U1 will receive an official name from the International Astronomical Union (IAU) in the future.
The discovery underscores the capabilities of JWST and indicates there is still much to learn about Uranus and its intricate system of moons and rings. “The discovery of this moon underscores how modern astronomy continues to build upon the legacy of missions like Voyager 2, which flew past Uranus on January 24, 1986, and gave humanity its first close-up look at this mysterious world,” said Maryame El Moutamid, a lead scientist at SwRI. “Now, nearly four decades later, the James Webb Space Telescope is pushing that frontier even farther.”
NASA’s Voyager 2 probe traveled past Uranus in January 1986, becoming the first and only spacecraft to visit the distant ice giant.
At that time, only five moons orbiting Uranus were known. The James Webb Space Telescope continues to expand our knowledge of the outer reaches of the solar system, offering a glimpse into the complex and mysterious nature of planets like Uranus.
