Giant Pool of Water Ice at Mars' South Pole

With a radar technique, astronomers have penetrated for the first time about 2.5 miles (nearly four kilometers) beneath the south pole’s frozen surface. The data showed that nearly pure water ice lies beneath.

Discovered in the early 1970s, layered deposits of ice and dust cap the North and South Poles of Mars. Until now, the deposits have been difficult to study closely with existing telescopes and satellites. The current advance comes from a probe of the deposits using an instrument aboard the Mars Express orbiter.

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