The ice giant Uranus is full of surprises, it seems. The latest of which is the discovery that several of its moons could be harbouring vast subterranean oceans of liquid water.
Ariel, Umbriel, Titania and Oberon are all now thought to be promising candidates, with two of these even being warm enough internally to potentially sustain life.
The discovery was made when scientists compared data from the Voyager 2 spacecraft to more recent data collected about other icy moons such as Pluto's Charon and Saturn's Enceladus by NASA's Galileo, Cassini, Dawn and New Horizons missions.
Voyager 2 flew by Uranus in 1986, but its instruments were not sensitive enough to detect the presence of oceans. However, the more recent data collected by other spacecraft has allowed scientists to better understand the structure and composition of Uranus' moons.
The discovery of these oceans on Uranus' moons is significant because it raises the possibility of habitability. Liquid water is essential for life as we know it, and the presence of oceans on these moons suggests that they may be able to support life.
In particular, Titania and Oberon are thought to be the most promising candidates for habitability. Both moons are large and have thick atmospheres, which could help to protect any life that might exist on their surfaces.