A team including space scientists from the Southwest Research Institute (SwRI) has made a major, exciting new astronomical discovery. They found a moon that had never been seen before orbiting Uranus! This detection was made during the very first observational transit of the exoplanet together with NASA’s James Webb Space Telescope on February 2, 2025. This new celestial body, designated S/2025 U1, adds to the existing inventory of 29 known moons surrounding the icy giant.
Scientists are not certain of its size, but they estimate the newly discovered moon has a diameter of only six miles (10 kilometers). That makes it one of the tiniest of Uranus’s elaborate moon system. Due to its small size and faintness, it was probably impossible to see during previous spacecraft flybys. Even Voyager 2, which provided humanity’s first close-up view of Uranus in 1986, didn’t catch it.
The Significance of the Discovery
Maryame El Moutamid, a leading member of the research team, highlighted the significance of this discovery.
“It’s a small moon but a significant discovery, which is something that even NASA’s Voyager 2 spacecraft didn’t see during its flyby nearly 40 years ago,” – Maryame El Moutamid.
The new moon orbits at an easily detectable distance of around 35,000 miles (56,000 kilometers) from Uranus’ center. It orbits in the planet’s equatorial plane, nestled between the orbits of two other previously discovered moons Ophelia and Bianca. Its almost circular orbit indicates that it might have formed close to where it orbits now.
The advanced capabilities of the NIRCam instrument, particularly its high resolution and infrared sensitivity, play a crucial role in detecting faint and distant objects that previous telescopes could not identify. This new discovery is a great example of how today’s astronomy continues to benefit from the footprints left by missions like Voyager 2.
“This object was spotted in a series of ten 40-minute long-exposure images captured by the Near-Infrared Camera (NIRCam),” – Maryame El Moutamid.
Uranus’s moons are oddly named after characters from plays by William Shakespeare and Alexander Pope. The discovery of S/2025 U1 welcomes another small moon to the strange family of Uranian moons. In doing so, it joined the ranks of the larger moons Miranda, Ariel, Umbriel, Titania, and Oberon for a total of 14.
Exploring Uranus’s Unique Moon System
Matthew Tiscareno, another member of the research team, highlighted the uniqueness of Uranus’s moon system:
The discovery provides an exciting glimpse of what’s possible. Perhaps there is even greater complexity in this moon system yet to be discovered! To Tiscareno, it stood out right away that this new moon is smaller and much fainter. In fact, it’s even less conspicuous than the smallest of the previously known inner moons.
“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,” – Matthew Tiscareno.
Already in its brief lifetime, the James Webb Space Telescope has revolutionized the frontier of astronomical research. Through its General Observer program, scientists from all over the world can propose investigations using Webb’s unprecedented, new instruments. El Moutamid remarked on this transformative capability:
The Future of Astronomy
As more discoveries arise from Webb’s observations, researchers anticipate unraveling further mysteries about Uranus and its intricate system of moons. The advancement in technology not only aids in identifying previously unseen celestial bodies but enriches humanity’s understanding of our solar system.
“Through this and other programs, Webb is providing a new eye on the outer solar system. 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,” – Maryame El Moutamid.
As more discoveries arise from Webb’s observations, researchers anticipate unraveling further mysteries about Uranus and its intricate system of moons. The advancement in technology not only aids in identifying previously unseen celestial bodies but also enriches humanity’s understanding of our solar system.