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Washington, December 3
According to one study, if life had ever existed on ancient Mars, it would have lived up to several miles below the surface of the Red Planet, possibly due to the subterranean melting of thick sheets of ice fed by geothermal heat.
The research, published in the journal Science Advances, examined various datasets on Mars to see whether heating via geothermal or underground heat would have been possible 4.1 billion to 3.7 billion years ago or in the Noachian era. .
They showed that the conditions necessary for the melting of the subsoil would be omnipresent on ancient Mars.
Even if Mars had a hot and humid climate 4 billion years ago, with the loss of the magnetic field, the thinning of the atmosphere and the consequent decline in global temperatures over time, liquid water may only have been stable at great depths. discovered the researchers. Therefore, life, if it ever originated on Mars, may have followed liquid water to progressively greater depths, they said.
“At such depths, life could have been sustained by hydrothermal (warming) activity and water-rock reactions. So, the subsoil could represent the longest-lived habitable environment on Mars,” said lead author Lujendra Ojha. assistant professor at Rutgers University – New Brunswick in the United States.
The study could help solve what’s known as the weak young sun paradox, a persistent key question in the science of Mars.
“Even as greenhouse gases like carbon dioxide and water vapor are pumped into the early Martian atmosphere in computer simulations, climate models continue to struggle to support a long-term hot and humid Mars,” Ojha said.
“My co-authors and I propose that the feeble young sun paradox can be reconciled, at least in part, if Mars previously had high geothermal heat,” he said.
The researchers noted that our Sun is a huge nuclear fusion reactor that generates energy by fusing hydrogen into helium. Over time, they explained, the Sun has gradually illuminated and heated the surface of the planets in our solar system.
According to the researchers, about 4 billion years ago, the Sun was much weaker, so the climate of early Mars should have been freezing.
However, the surface of Mars has many geological markers, such as ancient river beds and chemical markers, such as water-related minerals. These suggest that the Red Planet had abundant liquid water in the Noachian era, the researchers said. This apparent contradiction between the geological record and climate models is the feeble paradox of the young sun, they said.
On rocky planets such as Mars, Earth, Venus and Mercury, heat-producing elements such as uranium, thorium, and potassium generate heat via radioactive decay. In such a scenario, liquid water can be generated by melting at the bottom of thick ice sheets, even if the Sun was weaker than it is now.
On Earth, for example, geothermal heat forms subglacial lakes in the areas of the West Antarctic ice sheet, Greenland and the Canadian Arctic.
The researchers noted that a similar melting is likely to help explain the presence of liquid water on cold, freezing Mars 4 billion years ago. PTI
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