A Martian ice cap
The ice cap on Mars’ south pole shows that water is still on the planet—if only in a different state. In 2021, a team of researchers published a paper suggesting that liquid water may exist in subsurface lakes on Mars. “Either liquid water is common beneath Mars’ south pole or these signals are indicative of something else,” said Jeffrey Plaut, a research scientist at NASA’s Jet Propulsion Laboratory. But more recent work has challenged that hypothesis.
