“Multiple lakes beneath glaciers on Mars”

Mars’ south pole will be one of the prime sites for setting up a base if humans ever try that. In a region named Ultimi Scopuli, researchers have found three salty waterbodies underneath icy glaciers, giving a boost to prospects of both microbial extraterrestrial life on Mars and its habitability for humans. The results, published in Nature Astronomy on September 28, came from the analysis of data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) aboard the Mars Express spacecraft launched by European Space Agency in 2003. MARSIS sends out radio waves onto the Martian surface and interprets the waves that are reflected back. The scientists used the same processing techniques as they do to find liquid lakes beneath the ice sheets near the Earth’s poles. The team had found evidence of a 19-km-wide single saltwater body in 2018 through 29 observations made between 2012 and 2015. Now they have found stronger evidence from 105 additional observations for the existence of the larger waterbody and three smaller waterbodies that surround it. We are quite confident of our find, says ELENA PETTINELLI, professor of mathematics and physics at the Roma Tre University in Rome, Italy, and co-author of the research paper, in an interview with AKSHIT SANGOMLA. Excerpts:

- AKSHIT SANGOMLA

How sure are you about the presence of water bodies under Mars’ south pole?

We are as confident as we can be. We have examined every possible alternative interpretation of our data, but the only explanation consistent with the data is that the strong reflections observed by the radar come from distinct liquid bodies of water. The fact that we have obtained the same results using completely different data analysis methods makes us quite confident that the radar anomalies are caused by the presence of extended bodies of liquid water.

What more evidence is needed to prove this discovery for sure?

The silver bullet for this would be in-situ seismics (to be deployed with lander, rovers), which would allow not only to detect the top of such salty water bodies (radar cannot penetrate below the liquid interface), but also their bottom and geometry. Further, orbital radar data through new missions could shed more light on the presence of the other water bodies, perhaps, but rover-based geophysics (seismics, in particular) would be desirable.