Ariel, Uranus’s fourth largest moon, is thought to be made of equal ... used to detect liquid water oceans beneath Ariel’s icy surface.

However, Ariel’s surface—which has canyons, grooves and smooth regions—was found to contain carbon dioxide ice, particularly on the side of the moon that faces away from the direction it orbits.

Beneath the Earth's surface lies a vast ocean, which is three times larger than all the oceans on the planet. However, it is ...