Ariel, one of Uranus' icy moons, may once have concealed a vast ocean more than 100 miles (170 kilometers) deep beneath its frozen crust, according to new research. The findings add to growing evidence that Uranus' moons could have been ocean worlds in the distant past.
At 720 miles (1,159 kilometers) across, Ariel is smaller than many of the moons orbiting the planets Jupiter and Saturn. Yet, its surface is exceptionally bright and unusually complex, with ancient cratered terrain lying alongside much younger, smoother plains likely shaped by cryovolcanism, a type of volcanism that happens on icy bodies
