The Martian South Polar Ice Cap (image) American Geophysical Union Share Print E-Mail Caption This is the Martian South Pole. A new study in Geophysical Research Letters argues there needs to be an underground source of heat for liquid water to exist underneath the polar ice cap. Credit NASA. Usage Restrictions None Share Print E-Mail 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.