Astronomers have made an exciting discovery with the identification of a new moon orbiting Uranus. Using data from NASA’s James Webb Space Telescope, this previously undetected moon has been designated S/2025 U1. NASA announced the finding on August 19, 2025, adding to the constellation of known satellites surrounding the ice giant.
S/2025 U1 is a small moon, measuring about six miles in diameter—roughly equivalent to the length of 90 football fields laid end to end. Such diminutive size means that a person could walk around it in just a few hours. Observations of the moon were captured on February 2, 2025, utilizing the telescope’s Near-Infrared Camera over a series of ten 40-minute exposures. The James Webb Space Telescope’s advanced infrared technology was key in spotting this faint object, which earlier missions, like Voyager 2 in 1986, missed due to its low reflectivity and small scale.
The research team, led by experts at the Southwest Research Institute in Boulder, Colorado, included notable scientists such as Maryame El Moutamid and Matthew Tiscareno from the SETI Institute. El Moutamid remarked on the significance of the discovery, calling it small but important for enhancing our understanding of planetary systems. Tiscareno added depth to the excitement, discussing the complex relationship between Uranus’ inner moons and its rings, pointing to a “dynamic past” for the entire system.
S/2025 U1 orbits about 35,000 miles from Uranus’ center in a nearly circular path aligned with the planet’s equator. This positioning suggests that it formed in place rather than being captured from elsewhere. With its addition, Uranus now has 29 confirmed moons, alongside 14 other small inner satellites. While larger moons like Miranda and Titania have historical names from literature, the International Astronomical Union is set to assign a permanent name to S/2025 U1, reflecting a tradition of honoring significant cultural figures.
The moons of Uranus play a vital role in maintaining the structure of the planet’s 13 faint rings through gravitational interactions, and the discovery of S/2025 U1 could yield further insights into this intricate environment. From earlier discoveries, starting with William Herschel in 1787, to the extensive research conducted in more recent decades, the study of Uranus’ moons remains a rich field for astronomers seeking to unravel the secrets of our solar system.
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