Four of Uranus’ large moons likely contain internal oceans, new study suggests

A new study suggests that four of Uranus’ major moons - Ariel, Umbriel, Titania, and Oberon - likely contain internal oceans that could be dozens of miles deep. NASA scientists made this conclusion after re-analysing data from the agency's Voyager spacecraft, along with new computer modelling.

The study involved a review of results obtained from NASA's Voyager 2 missions to Uranus during the 1980s, as well as from observations made from the ground. The researchers used additional information from other NASA missions including Galileo, Cassini, Dawn, and New Horizons missions (which identified oceanic worlds) to built computer models.

The modeling was used to determine that the Uranian moons' surfaces are porous enough to retain internal heat, which could support an ocean beneath. They also identified a potential heat source in the moons' rocky mantles that could sustain a warm environment, especially for Titania and Oberon, making them potentially habitable. Investigating the composition of the oceans could provide insight into materials found on the moons' icy surfaces. Recent observations suggest Ariel and Miranda may have had active geological features that could support the presence of water. However, thermal modeling suggests that Miranda is unlikely to have sustained water for long and is probably frozen now.

"I to the world am like a drop of waterThat in the ocean seeks another drop..."New NASA research suggests four of Uranus’ largest moons, some named for Shakespeare characters, likely contain an ocean layer between their cores and icy crusts. https://t.co/3Jj0FuTB49 pic.twitter.com/vZ7NRQcmxJ

— NASA Solar System (@NASASolarSystem) May 4, 2023

According to the study, internal heat alone is not the only factor contributing to the existence of subsurface oceans in the Uranian moons. The researchers discovered that chlorides and ammonia, which is known to act as antifreeze, are probably abundant in the oceans of the largest moons,

Furthermore, the modeling indicates that salts likely present in the water could serve as another source of antifreeze, helping to maintain the moons' internal oceans.

"We need to develop new models for different assumptions on the origin of the moons in order to guide planning for future observations," said lead author Julie Castillo-Rogez of NASA's Jet Propulsion Laboratory in Southern California.