Another study says Mars does not have liquid water under its south pole

The uncertainty of science: A new study now claims that the presumed detection of lakes of liquid water under the Martian southern polar ice cap in 2018 was likely wrong, and that the detection was more likely volcanic rock.

The researchers think their conclusion — volcanic rock buried under ice — is a more plausible explanation for the 2018 discovery, which was already in question after scientists calculated the unlikely conditions needed to keep water in a liquid state at Mars’ cold, arid south pole.

“For water to be sustained this close to the surface, you need both a very salty environment and a strong, locally generated heat source, but that doesn’t match what we know of this region,” says the study’s lead author, Cyril Grima, a planetary scientist at The University of Texas at Austin Jackson School of Geosciences.

So my readers know how uncertain all of this is, note that the 2018 discovery of underwater liquid water was later confirmed by other scientists in 2020, then rejected by different researchers in 2021, who claimed it was clay instead.

In other words, the scientists have some inconclusive data that could mean many different things, either water, clay, volcanic rock, or maybe something else that someone hasn’t yet suggested. To really answer the question will require far more data, with some like required in situ on Mars itself.

Scientists find previously unknown deposits of CO2 on Mars

Scientists find a gigantic and previously unknown deposit of CO2 at Mars’ south pole.

“We already knew there is a small perennial cap of carbon-dioxide ice on top of the water ice there, but this buried deposit has about 30 times more dry ice than previously estimated,” said Roger Phillips of Southwest Research Institute in Boulder, Colo. Phillips is deputy team leader for the Mars Reconnaissance Orbiter’s Shallow Radar instrument and lead author of the report. . . . “When you include this buried deposit, Martian carbon dioxide right now is roughly half frozen and half in the atmosphere, but at other times it can be nearly all frozen or nearly all in the atmosphere,” Phillips said.

What this discovery means is that, depending on Mars’ orbital circumstances, its atmosphere can sometimes be dense enough for liquid water to flow on its surface.