James Webb Space Telescope Discovers New Moon Orbiting Uranus

NASA's James Webb Space Telescope has identified a previously unknown moon orbiting Uranus, increasing the planet's known satellites to 29.

The newly discovered moon, provisionally designated S/2025 U1, is estimated to be approximately six miles (10 kilometers) in diameter. Its small size likely contributed to its eluding detection by earlier missions, including Voyager 2's 1986 flyby.

S/2025 U1 is located about 35,000 miles (56,000 kilometers) from Uranus' center, orbiting between the moons Ophelia and Bianca. Its nearly circular orbit suggests it may have formed near its current location.

The discovery was made using the telescope's Near-Infrared Camera (NIRCam) during observations in February 2025.

"This object was spotted in a series of 10 40-minute long-exposure images captured by the Near-Infrared Camera (NIRCam)," said Maryame El Moutamid, a lead scientist in SwRI's Solar System Science and Exploration Division based in Boulder, Colorado.

Uranus' moons are traditionally named after characters from the works of William Shakespeare and Alexander Pope. The International Astronomical Union will approve a name for S/2025 U1 in accordance with this convention.

"No other planet has as many small inner moons as Uranus, and their complex inter-relationships 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, a member of the research team.

This discovery underscores the James Webb Space Telescope's capability to enhance our understanding of the outer solar system, building upon the legacy of missions like Voyager 2.