Scientists believe they’ve found more evidence confirming the presence of a large reservoir of liquid water under the surface of Mars first discovered back in 2018. In fact, they believe they’ve found three more subsurface saltwater lakes surrounding that main one — a huge discovery, seeing as those lakes are potential habitats for life. As Nature notes in its post about the scientists’ paper, the first finding was met with lot of skepticism because it was only based on 29 observations from 2012 to 2015. This study and its findings were based on 134 observations made between 2012 and 2019.
The team used data from a radar instrument on the European Space Agency’s (ESA) Mars Express spacecraft to investigate the planet’s southern polar region. Mars Advanced Radar for Subsurface and Ionosphere Sounding or MARSIS, as the instrument is called, is capable of sending out radio waves that bounce off materials on the planet’s surface. Different materials reflect those signals differently, and the same technique is used to find subsurface glacial lakes here on Earth.