NA new study by Lonneke Roelofs from Utrecht University challenges our understanding of water on Mars, which could impact the search for life on the Red Planet. The study, published in the journal Communications Earth and Environment, suggests that Martian gullies—channels previously thought to have been created by liquid water—may also have been formed by evaporating “carbon dioxide ice.” Discuss© Ferra
“This find has implications for our understanding of water on Mars in general, and therefore for the search for life,” explains Roelofs. Mars' thin atmosphere, made mostly of CO2, allows winter temperatures to drop to -120°C, which is cold enough for CO2 to freeze, turning directly from gas to ice, bypassing the liquid phase. Like frost on Earth, this CO2 ice sublimates (turns directly into a gas) during warmer spring periods. “This sublimation is highly explosive due to the low air pressure on Mars,” says Roelofs. “The resulting gas creates enormous pressure, pushing sedimentary rocks apart.” This could significantly change the Martian landscape even in the absence of liquid water.
“The study shows that the likelihood of life existing on Mars is low,” says Roelofs. “This is because stable liquid water is important for the origin of life. Although the presence of water on Mars has been confirmed, the possibility that these gullies were formed by the influence of CO2 suggests shorter periods when liquid water flowed freely.”
“We do not deny the existence of water on Mars,” Roelofs explains. . “However, the possibility that ice from CO2 formed these gullies pushes the presence of liquid water even further into the past, potentially shortening the time of the origin of life.”