A team of scientists at the Southwest Research Institute, using photography commissioned from NASA’s James Webb Space Telescope, have discovered a previously unknown moon in our solar system that’s in a “nearly circular” orbit around Uranus. Just six miles in diameter, our little neighbor is so small that no telescope has been powerful enough to notice it, not even on the Voyager 2 spacecraft that flew past Uranus 40 years ago. But a series of ten 40-minute exposures by Webb’s Near-Infrared Camera finally revealed it, giving us a little more complete of a picture of our solar system.
The moon, currently called S/2025 U1, orbits just 35,000 miles from the center of Uranus (before you start: no jokes, to jail with you), or only about 15% as far away as our Moon is from Earth. As with its fellow 28 moons, this plants it right within the rings surrounding the planet. “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,” said research team member Matthew Tiscareno.
How exactly the planets of our solar system got their various rings and moons remains a matter of active study, but in many cases, they are likely related. If a moon is ripped apart by the gravity of its neighbor world, the scattered debris can continue to orbit and become a ring. Over time, if that debris starts to bunch together, exert gravity, and pull in more debris, it could become… a moon. Webb’s new discovery provides an important new way to examine that process.
Shakespeare in space
But first the baby will need a name, as S/2025 U1 isn’t exactly inspiring. Uranus’ other moons are far more dramatically inclined, with names like Ophelia, Bianca, Juliet, even Puck. If those sound familiar, it’s because they’re all from the works of William Shakespeare and Alexander Pope. Expect the International Astronomical Union, which names celestial bodies, to take a trip to the theater before it settles on a name. Hopefully not Shrew.
In the meantime, the Webb telescope will continue its journey way out at the second Lagrange point of the Earth and Sun, quietly taking photographs in the deepest darkness that any telescope has ever experienced. While NASA manages the satellite itself, science teams are able to request missions for it as part of the General Observers program. That’s exactly how little S/2025 U1 was found. You might think you know your neighbors, but it turns out, there may be more to meet.
