A study published last year in Science magazine shows that liquid water is present under the southern polar ice cap on Mars.
Now, a new study in the journal AGU Geophysical Research Letters says there must be an underground heat source for liquid water under the polar ice cap.
The new study does not take into account whether there is liquid water. Instead, the authors suggest that recent magmatic activity – the formation of a magma chamber over the last few hundred thousand years – must have occurred under the surface of Mars to have enough heat to produce liquid water under a kilometer – and – thick ice cap. On the other hand, the authors of the study argue that if there was no recent magmatic activity beneath the surface of Mars, then liquid water under the ice cap is unlikely.
"Different people can go differently with this, and we're really interested in seeing how the community reacts to it," says Michael Sorry, a Lunar and Planetary Lab at the University of Arizona, and co-author of the new document.
The potential presence of recent underground magmatic activity on Mars adds to the notion that Mars is an active planet, geologically speaking. This fact can give scientists a better understanding of the evolution of the planets over time.
The new study aims to continue the debate about the possibility of Mars's liquid water. The presence of liquid water on the Red Planet is important for potentially finding life outside the Earth and can serve as a resource for future human research on our neighboring planet.
"We think that if there is any life, it probably has to be protected from the surface of the radiation," says Ali Bramson, a research associate at the Lunar and Planetary Laboratory at the University of Arizona and co-author of the new paper. "If magmatic processes still exist today, they may be more common in the recent past and could provide a broader base melt, which could provide a more favorable environment for liquid water, and thus, perhaps, life."
Examining the environment
Mars has two giant ice sheets that are a few kilometers thick. On Earth it is customary for liquid water to be present under thick ice sheets, as the warmth of the planet causes the melting of the ice when it meets the earth's crust.
In a report published last year in Science, scientists say they have found a similar phenomenon on Mars. They argue that radar observations have found evidence of liquid water at the base of the southern polar cap on Mars. However, the study of science does not address the question of how liquid water could be obtained there.
Mars is much cooler than Earth, so it's unclear what kind of environment will be needed to melt the ice at the base of the ice cap. Although previous research has examined whether liquid water may exist at the base of Mars ice caps, nobody has ever looked at the specific place where science research claims to have found water.
"We thought there was plenty of room to know if [the liquid water] is it real, what environment should melt the ice in the first place, what temperatures will you need, what kind of geological process will you need? Because under normal conditions it has to be too cold, "Sorrie said.
Looking for heat
The authors of the new study first suggested that the detection of liquid water under the ice cap was correct and then worked to find out what parameters are necessary for the existence of the water. They made physical modeling on Mars to understand how much heat came from the interior of the planet and whether the base of the ice cap could have enough salt to melt the ice. Salt significantly reduces the melting point of the ice, so it is believed that salt can cause melting at the base of the ice cap.
The model showed that only salt would not raise the high enough temperature to melt the ice. Instead, the authors propose to have extra heat coming from the inside of Mars.
A believable source of heat would be volcanic activity in the underground surface of the planet. The authors of the study claim that the magma from the deep inside of Mars has risen to the surface of the planet some 300,000 years ago. It did not break the surface, like a volcanic eruption, but gathered in a magma chamber below the surface. By cooling the magma chamber, it released the heat that melted the ice at the base of the ice sheet. Chamber magma still provides heat to the ice sheet to generate liquid water today.
The idea of volcanic activity on Mars is not new – there is much evidence of volcanism on the surface of the planet. But most of the volcanic peculiarities of Mars are millions of years ago, leading scientists to believe that volcanic activity beneath and above the surface of the planet has long stopped.
However, the new study suggests that there may be more recent underground volcanic activity. And if there was a volcanic activity happening hundreds of thousands of years ago, it is likely to happen today, according to the authors of the study.
"It would mean that inside the Mars there is still an active formation of a magma chamber and that's not just cold, some dead space inside," Brassson said.
Jack Holt, a professor at the Lunar and Planetary Laboratory at the University of Arizona, said the question of how water could exist under the southern polar hat immediately remembered it after publishing the scientific paper and adding new paper. an important limitation for the possibility of water being there. He said he would most likely add a debate to the planetary scientific community on the finding, and pointed out that more research needed to be done to evaluate it.
"I think it was a great idea to do this type of modeling and analysis because you have to explain the water if it's there and that's really an important part of the puzzle," says Holt, who does not participate in the new research, but talks with the authors of the study before submitting the document. The original paper just left it hanging. There may be water there, but you have to explain it, and these guys have done a good job of saying what is required and that salt is not enough.
Reference: Mars Water with Salt Grain: Local heat anomalies are needed for the basin melting of ice on the South Pole today, Michael Sorry and Ali M. Bramson (Lunar and Planetary Laboratory, Arizona University, Tucson, AZ, USA), 2019 February, 12, Geophysical Research Letters [https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL080985],
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