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  • Denis Pepin

Mars: A Once Watery World with a Breath of Air?

Updated: May 9

A panoramic view of a Martian landscape showcasing a dry riverbed winding through towering red cliffs and dunes, under a hazy sky indicative of airborne particles, reminiscent of water's ancient path and the subtle forces of wind.
Rediscovering Mars: Unearthing the Secrets of Ancient Rivers and the Whispers of Martian Winds. (CyberNesco)

The desolate red landscape of Mars, with its towering volcanoes and vast canyons, may hold secrets to a bygone era. Recent discoveries by NASA's Curiosity rover hint at a time when Mars wasn't the cold, dry desert it is today. Evidence suggests it may have been a world with flowing water, a thicker atmosphere, and perhaps, even the potential to support life.

The key to unlocking this Martian past lies in manganese-rich sandstones found within the Gale Crater. These rocks, analyzed by Curiosity's ChemCam instrument, hold a surprising signature – manganese oxides. On Earth, the formation of these oxides requires a highly oxidizing environment, often influenced by the presence of atmospheric oxygen. This discovery throws a curveball at our understanding of ancient Mars. Could it be that the Red Planet once sported an oxygen-rich atmosphere, similar to our own?

The implications are significant. An oxygen-rich atmosphere on Mars billions of years ago could have provided a crucial ingredient for life as we know it. Early Earth, during its nascent stages, possessed a similar atmosphere, believed to be a key factor in the emergence of life. The Martian environment, with its potential for liquid water and oxygen, could have mirrored the conditions that fostered life on our own planet.

However, the story doesn't end there. Several mysteries remain. The exact mechanism for the formation of these manganese oxides is still under debate. One theory suggests that they may have precipitated from water, influenced by the presence of dissolved oxygen produced by sunlight interacting with water vapor in the atmosphere. Another possibility points towards the involvement of ancient microbes, utilizing manganese as part of their metabolic processes, similar to some life forms on Earth. While Curiosity hasn't found definitive proof of life on Mars, the presence of manganese oxides opens exciting avenues for further exploration.

Another question mark hangs over the origin of the oxygen itself. Where did it come from in a Martian atmosphere that is currently so thin and devoid of free oxygen? One possibility lies in the planet's early history. Mars may have possessed a stronger magnetic field billions of years ago, shielding it from the harsh solar wind that strips away atmospheric particles today. This magnetic field, coupled with volcanic activity releasing gases, could have created a thicker atmosphere rich in carbon dioxide and water vapor. Sunlight interacting with these molecules might have then produced oxygen through photolysis, a process where light breaks apart molecules.

Alternatively, the oxygen may have originated from the breakdown of water molecules by high-energy ultraviolet radiation from the young Sun. However, this theory faces challenges as it's unclear if Mars' magnetic field was strong enough to shield the planet from such radiation in its early days. Further exploration and analysis of Martian rocks and atmospheric composition are needed to unravel this particular mystery.

The Curiosity rover's findings are just the beginning. Missions such as the forthcoming Perseverance rover—originally part of the Mars 2020 mission—and the ExoMars Rosalind Franklin rover, both slated for deployment later in the decade, are designed to conduct in-depth exploration. These rovers will be equipped with advanced instruments designed to search for biosignatures, the chemical fingerprints of past or present life forms, within Martian rocks and soil. They will also analyze the composition of the current Martian atmosphere, providing valuable insights into the planet's history and potential for past habitability.

The search for signs of life on Mars extends beyond rovers. Orbiters like Mars Reconnaissance Orbiter and MAVEN (Mars Atmosphere and Volatile Evolution Mission) are continuously studying the Martian surface and atmosphere from above. They map geological features, search for signs of past water activity, and analyze the composition of the thin Martian air. These missions, along with data collected by landers like InSight, are building a comprehensive picture of the Red Planet.

Back on Earth, sophisticated laboratories are analyzing Martian meteorites that have fallen to our planet. These rocks, ejected from Mars by ancient impacts, offer a unique opportunity to study Martian material directly. By analyzing their composition and trapped gases, scientists can glean valuable information about the Martian past, including the potential for past habitability.

The quest to understand Mars is not just about scientific curiosity. It's about piecing together the puzzle of our own solar system's history, understanding the potential for life beyond Earth, and perhaps even informing the search for habitable exoplanets. As we continue to explore the Red Planet, the possibility that Mars once held a breath of air and liquid water becomes increasingly intriguing. The coming years promise exciting discoveries that could rewrite our understanding of Mars and its potential to harbor life.


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