Why the moons of Uranus are so exciting
Ariel, Miranda, Umbriel, Titania, and Oberon are the five largest of the Uranus System’s 27 moons.
“Uranus’ large moons are really weird,” said Cartwright. “They are all candidate ocean worlds that may have internal saltwater oceans, perhaps similar to Ceres and Enceladus — and they may have harbored life in the past.”
Those five largest moons have dark but surprisingly young surfaces that could be rich in organics — the building blocks of life as we know it. They also appear to be geologically active.
“They display evidence for recent geologic resurfacing, including possible cryovolcanic activity and high internal heat,” said Chloe Beddingfield, a planetary scientist and astronomer at NASA Ames Research Center and leading expert on Uranian moon geology. “Investigation of these moons would enhance our knowledge of where potentially habitable bodies exist in our Solar System.”
What Voyager 2 saw
All five moons — and some of Uranus’ other 22 moons — would likely be imaged by a flagship mission. For some, though, it wouldn’t be the first time.
“The snapshots of the Uranian moons’ surfaces collected during Voyager 2’s brief flyby in 1986 revealed ubiquitous evidence for endogenic geologic activity, in particular on Ariel and Miranda,” said Cartwright. Endogenic activity is planetary scientist-talk for plate tectonics, which may have occurred recently on these two moons.
Named after characters in William Shakespeare’s play “The Tempest,” Ariel and Miranda are similar in size to Enceladus. Both have surfaces that appear to have been fractured and then resurfaced by water and ammonia-rich lavas. That suggests internal heat. However, there are some major differences between Ariel and Miranda.