Much more liquid water may lie beneath the south pole of Mars than scientists had thought — or there may be something going on down there that they don’t fully understand.
In 2018, researchers analyzing radar data gathered by Europe’s Mars Express spacecraft announced they’d found evidence of a big subsurface lake in the Red Planet’s south polar region. The lake appears to be about 12 miles (19 kilometers) wide, and it lies about 1 mile (1.6 km) beneath the dry, frigid surface, the scientists reported.
The same core research team soon followed up on the find, using the same Mars Express instrument — Mars Advanced Radar for Subsurface and Ionospheric Sounding, or MARSIS for short — to study the subsurface in a wide area around the apparent lake. This work turned up evidence for three more underground lakes, each of them about 6 miles (10 km) wide, the scientists reported in a study last year.