Researchers from Roma Tre University in Italy have confirmed the existence of four large lakes under the ice at Mar’s south pole.
The findings come after a study in 2018 that detected a similar lake in the same region. Having only been based upon 29 observations between 2012 and 2015, however, many were skeptical of its existence.
Now, the latest study, published on 28 September in Nature Astronomy, has confirmed not only its existance but also that of three other similar lakes in the same area, from a larger data set of 134 observations between 2012 and 2019.
For the study, the researchers used a radar instrument on the European Space Agency’s Mars-orbiting spacecraft known as ‘Mars Express’. The instrument, known as the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), was used to send radiation waves that bounced off layers of material on the planet’s surface and subsurface to indicate its makeup.
From these readings, the researchers were able to detect some areas of high reflectivity that indicated the presence of bodies of liquid water trapped under over a kilometer of ice. All in all, they say that the lakes are spread out of around 75,000 square kilometers. The largest is around 30 kilometers in diameter and is surrounded by three smaller ones, each at a few kilometers in width.
While some see the latest evidence of these lakes as substantial, others are more skeptical. Mike Sori, for example, a planetary geophysicist at Purdue University in Indiana, said that the ‘lakes’ are more likely to be made of slush or sludge than water. Meanwhile, Jack Holt, a planetary scientist at the University of Arizona, says that although the data seems fine, there is sufficient heat flow to support brine to form, even under an ice cap.