Remnants of water once found on the surface of Mars may be hidden in a handful of small lakes below the Red Planet’s south pole, and more could exist. For decades researchers have suspected that water lurks below the polar ice caps of Mars, just as it does here on Earth. In 2018 scientists detected evidence for such a reservoir on the Red Planet, signs of a lake about 19 kilometres across and hidden below about 1.5 kilometres of ice at the south pole of Mars.
An artist’s depiction of Mars covered in water, as it may have been about 4 billion years ago
© NASA/GSFC
At the time the researchers said studying this underground pool of water could yield insights on the past and present chances for life on Mars. However, scientists had many more questions than answers about the origin, composition and longevity of this lake and its water. To learn more about this hidden water, researchers have used the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board the European Space Agency’s Mars Express to scan a 250-by-300-kilometre area surrounding the suspected underground lake.