The case of the Vanishing Martian Atmosphere

For years,scientists have theorized about the fate of Mars’ once-thick atmosphere and abundant water. Now, a groundbreaking revelation provides direct evidence of a key culprit: atmospheric sputtering. This erosion process, driven by solar wind ions, is believed to have played a significant role in stripping away the Martian atmosphere over billions of years.

The key to this discovery lies with NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft. As NASA’s MAVEN mission page explains, it’s uniquely positioned to observe this phenomenon.

MAVEN’s Crucial Role

MAVEN, orbiting Mars since September 2014, is equipped with instruments capable of detecting both the solar wind’s electric field and the composition of the Martian upper atmosphere. researchers meticulously analyzed MAVEN’s data, searching for simultaneous observations of these factors.

The only spacecraft with the equipment and orbital configuration to make these observations is NASA’s MAVEN.

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Their efforts paid off. Above an altitude of 350 kilometers (217 miles), they found that argon densities varied depending on the orientation of the solar wind’s electric field. In contrast, argon densities at lower altitudes remained consistent.

Argon: A Tracer of Atmospheric Erosion

Argon, an inert gas, serves as a valuable tracer for atmospheric sputtering.The research team focused on different isotopes of argon, which are atoms of the same element with varying numbers of neutrons.

The results revealed that lighter argon isotopes where being preferentially removed, leaving behind an excess of heavier argon. This isotopic discrepancy strongly suggests active sputtering is occurring.

further bolstering this conclusion were observations made during a solar storm in January 2016. The increased solar wind activity dramatically amplified the evidence of sputtering.

As the original report notes:

During this time, the evidence of sputtering became substantially more pronounced. Not only does this support the team’s finding that argon density variations at high Martian altitudes are the result of sputtering, it demonstrates what conditions may have been like billions of years ago, when the sun was younger and rowdier, undergoing more frequent storm activity.

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Implications for Mars’ Past and Future

These findings provide crucial insights into the processes that shaped the Martian atmosphere over billions of years. The sun’s early activity, characterized by more frequent and intense solar storms, likely accelerated atmospheric sputtering, contributing to the loss of water and the change of mars into the cold, arid planet we know today.

The research, published in the journal Science Advances, underscores the importance of understanding solar wind interactions with planetary atmospheres, not only for Mars but also for other potentially habitable worlds.

FAQ: Understanding Atmospheric sputtering on Mars

• What is atmospheric sputtering? It’s an erosion process where solar wind ions bombard a planet’s atmosphere, knocking away atmospheric particles.
• How did scientists observe it on Mars? NASA’s MAVEN spacecraft detected variations in argon density in the upper atmosphere, correlated with solar wind activity.
• Why is this crucial? It helps explain how Mars lost its atmosphere and water over billions of years.
• What role did the Sun play? The young Sun was more active, with more frequent solar storms, accelerating the sputtering process.