Astronomers have unveiled a tiny moon circling Uranus after poring over images captured by the James Webb Space Telescope’s Near-Infrared Camera. The detection was initially made during a Webb observation on February 2, 2025. The NIRCam instrument’s high resolution and infrared sensitivity make it especially adept at detecting faint, distant objects that were beyond the reach of previous observatories.

This tiny moon, designated S/2025 U1, emerged against the planet’s icy blue disc. No previous mission, including Voyager 2’s 1986 flyby, managed to achieve such a detection. The image shows the new moon as well as 13 of the 28 other known moons orbiting the planet. The planet appears blue with a large, white patch taking up the bottom half. Around the planet is a system of nested rings. The outermost ring is the brightest, while the innermost ring is the faintest.

This object was identified in ten 40-minute-long exposure frames taken by NIRCam. By tracking its consistent motion across each image, researchers confirmed it wasn’t a background star or an artifact but a bona fide Uranian satellite. S/2025 U1 orbits roughly 35,000 miles (56,000 km) from Uranus’s center, nestled between the moons Ophelia and Bianca. Based on its faint glow and assuming an albedo similar to Uranus’s other tiny companions, the new moon spans just six miles (10 km) in diameter, making it not only the planet’s 29th confirmed satellite but also the smallest inner moon yet found.

Its discovery highlights the intricate ballet of rings and shepherd moons encircling Uranus. JWST’s infrared sensitivity peels back the glare of the planet’s bright atmosphere and nearby rings, revealing objects too dim for ground-based telescopes or earlier spacecraft. The new moon is the 14th member of the intricate system of small moons orbiting inward of the largest moons Miranda, Ariel, Umbriel, Titania, and Oberon. (All the moons of Uranus are named after characters from Shakespeare and Alexander Pope.)

Before S/2025 U1 can earn a proper name, the International Astronomical Union (IAU) will review the team’s findings and select an official moniker. In the meantime, Webb’s General Observer program continues to cast a fresh eye on the outer solar system, inviting investigators worldwide to probe distant worlds and shatter old limits.

Beyond this discovery, scientists plan follow-up JWST observations in late 2026 to refine S/2025 U1’s orbit and surface properties. Mapping such tiny moons helps improve models of ring-moon interactions and could shed light on the processes that shaped Uranus’s unique axial tilt. Each new fragment of data brings us closer to understanding how ice giants form and evolve, and Webb’s ongoing surveys will likely uncover even more surprises in the far reaches of our solar system.