Uranus's moon Ariel (IMAGE) University of Texas at Austin Caption Ariel, Uranus’s fourth largest moon, is thought to be made of equal parts rock and ice. A new computer model developed at the University of Texas Institute for Geophysics could be used to detect liquid water oceans beneath Ariel’s icy surface. Credit NASA/JPL Usage Restrictions Credit must be given to the creator. License CC BY Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.