“We just need to go back” – Uranus’ moon Ariel may have hidden a 100-mile-deep ocean

Ariel, one of Uranus’ moons, may once have contained a subsurface ocean more than 100 miles deep beneath its fractured icy shell. The finding, combined with similar evidence from Miranda, suggests the distant Uranian system could harbor multiple hidden ocean worlds. “We just need to go back” – Uranus’ moon Ariel may have hidden a 100-mile-deep ocean.

Research published in Icarus explores how that hidden ocean may have changed over time and suggests it could once have been more than 100 miles (170 kilometers) deep. By comparison, the Pacific Ocean has an average depth of about 2.5 miles (4 kilometers). "Ariel is pretty unique in terms of icy moons," said paper co-author Alex Patthoff, a Planetary Science Institute senior scientist.

A Moon With a Surprisingly Violent Past Ariel is the brightest of Uranus’ moons and the second closest to the planet. At only 720 miles (1,159 km) across (the distance from PSI in Tucson to Salt Lake City, Utah), it ranks as the fourth-largest moon in the Uranian system. Despite its relatively small size, Ariel has an unusually complex surface.