Ariel, one of Uranus’ icy moons, might have hidden a massive ocean beneath its frozen surface, according to recent research. This idea adds to the growing belief that some moons of Uranus could once have been ocean worlds.
Ariel is 720 miles (1,159 kilometers) wide. While it’s smaller than many moons of Jupiter and Saturn, its surface is unique. It has bright, varied terrain with ancient craters next to younger, smoother plains. These younger areas are likely shaped by cryovolcanism, a type of ice-related volcanic activity.
The study, led by Caleb Strom from the University of North Dakota, aimed to understand Ariel’s interior and the way its orbit changed over time. Researchers looked at how Uranus’ gravity would have affected Ariel, stretching and squeezing it in the past.
The findings revealed that Ariel’s orbit was once much more eccentric—about 40 times more than it is today. This means it could have undergone considerable changes, similar to Europa, one of Jupiter’s moons that shows signs of geological activity.
Researchers believe the large cracks and ridges on Ariel’s surface suggest it was flexing over a liquid layer, possibly a vast ocean or a smaller one with stronger orbital stress. “We need an ocean to explain the fractures on Ariel’s surface,” said study co-author Alex Patthoff from the Planetary Science Institute.
This research follows a previous study that found similar evidence of a subsurface ocean on another Uranus moon, Miranda. The two findings point towards the possibility that Uranus may have multiple ocean-bearing satellites.
Subsurface oceans are exciting in planetary science because they might harbor life. Liquid water, combined with heat from tidal forces or radioactive decay, can create conditions suitable for biological activity, even far from the sun.
While we don’t know when Ariel’s ocean formed or if it still exists, these findings shed light on how oceans might evolve in the icy realms of our solar system.
Many scientists are calling for a mission to Uranus to explore these mysteries further. The proposed Uranus Orbiter and Probe, recommended by the National Academies’ planetary science decadal survey, could give us valuable insights into the planet’s tilt, ring system, and moons. Although funding for this mission is still pending, scientists believe it could lead to groundbreaking discoveries, much like NASA’s Cassini mission did for Saturn, revealing astonishing insights about its rings and moons.
So far, past missions have only captured images of Ariel’s southern hemisphere. The new models from this study can help guide future missions, which might uncover even more features in the moon’s northern regions. “We just need to go back to the Uranus system and see for ourselves,” Nordheim, another co-author, emphasized.
The study was published in the journal Icarus in January 2026. You can read more about their findings here.
