Mars' buried polar 'lakes' may just be frozen clay
Bright reflections that radar detected beneath the south pole of Mars may not be underground lakes as previously thought but deposits of clay instead, a new study finds.
For decades, scientists have suspected that water lurks below the polar ice caps of Mars, just as it does here on Earth. In 2018, researchers using the MARSIS radar sounder instrument on the European Space Agency's Mars Express spacecraft detected evidence for a lake hidden beneath the Red Planet's south polar ice cap, and in 2020, they found signs of a number of super-salty lakes there. If these lakes were remnants of water that was once on the surface, these reservoirs may have once harbored life and may still, the scientists noted.
However, in order to form and maintain liquid water at this spot on Mars, an implausible amount of heat and salt may be needed, given what is currently known about the Red Planet, according to the lead author of the new study, Isaac Smith, a planetary scientist at York University in Toronto, and his colleagues.
The bright white region of this image, captured by Europe's Mars Express spacecraft in December 2012, shows the icy cap that covers Mars’ south pole, composed of frozen water and frozen carbon dioxide. (Image credit: ESA/DLR/FU Berlin/Bill Dunford)