NASA’s James Webb Telescope finds small new moon orbiting Uranus

Scientists at the Southwest Research Institute (SwRI) in Colorado have discovered a tiny new moon orbiting Uranus using NASA’s James Webb Space Telescope.

The moon, designated S/2025 U1, measures only about 6 miles (10 kilometres) in diameter, making it too small to have been detected by previous missions or telescopes, including NASA’s Voyager 2, which flew past Uranus in 1986. With this finding, the total number of known Uranian moons has risen to 29.

Details of the discovery

According to Maryame El Moutamid, a lead scientist at SwRI’s Solar System Science and Exploration Division, the moon was identified through a series of 10 40-minute-long long-exposure images, taken by the Near-Infrared Camera (NIRCam) aboard the James Webb Space Telescope.

Due to its extremely small size — just a fraction of Earth’s moon — earlier spacecraft and ground-based observations failed to detect it, NDTV reported.

The newly discovered moon, S/2025 U1, is now the 14th member of the complex system of small moons that orbit inside Uranus’s five largest moons — Miranda, Ariel, Umbriel, Titania, and Oberon.

It follows a nearly circular orbit about 35,000 miles (56,000 kilometres) from Uranus’s centre, indicating that it likely formed near its current position among the planet’s other small inner moons.

With this addition, Uranus is now known to have 29 moons, making it one of the most densely populated moon systems in the solar system. Many of these moons are tiny and orbit very close to the planet.

Scientists suggest that the discovery of S/2025 U1 could point to the existence of more hidden moons or undetected ring fragments still awaiting discovery, showing how much remains unknown about Uranus.

Back in 1986, when Voyager 2 flew past Uranus, it detected only five moons. In contrast, the James Webb Space Telescope has now managed to spot much smaller moons that Voyager missed, revealing unexpected details around familiar planets.

By studying these tiny moons and Uranus’s ring system, scientists hope to gain deeper insights into how the Uranian system formed and evolved. Each new discovery adds another piece to the puzzle, bringing researchers closer to understanding the history and mysteries of this distant, icy world.