Webb Uncovers 10-Kilometer Uranus Moon, Raising Total to 29
NASA’s James Webb Space Telescope detected a faint 10-kilometer moon, S/2025 U1, orbiting near Uranus’s inner rings—an object missed by Voyager 2 and Hubble but revealed by Webb’s long infrared exposures. The moon orbits about 56,000 km from Uranus’ center, completing a near-circular orbit in under half a day, and is part of the inner Uranian system, helping explain ring–moon interactions. The discovery raises Uranus’s known moon count to 29 and suggests more tiny bodies may lurk in glare; future missions could map rings and refine the orbits and masses of these small moons.