This week, NASA scientists announced a puzzling and groundbreaking discovery about the Martian atmosphere. They observed atmospheric sputtering for the first time, a process that’s driven by solar winds. This groundbreaking discovery appeared in the journal Science Advances on a research team headed by Shannon M. Curry. Their study provides key insights into how this process has contributed to Mars’ evolution into the cold, dry planet we see today.
Mars, by contrast, has no such planet-wide magnetic field, allowing solar wind to interact with the Red Planet’s atmosphere with more impunity. This process initiates the atmospheric sputtering. Continuing from the previous post energetic particles from the solar wind collide with atmospheric gases and sputter individual atoms and molecules into space. New studies suggest atmospheric sputtering has been much more widespread, operating over geologic timescales. This process is slowly leading to the depletion of water from both Mars’ surface and atmosphere.
Insights from the Research
The detection of atmospheric sputtering was made possible through an analysis of nine years’ worth of satellite data collected from NASA’s MAVEN probe, which has been orbiting Mars for over 11 years. One key finding is that argon densities at 350 kilometers above the Martian surface vary greatly based on the sun’s position. In comparison, the densities near the roadway surface are largely consistent.
Researchers discovered that solar storms amplify these differences in argon densities, showcasing the dynamic nature of Mars’ atmospheric interactions with solar activity. As for the new data, it seems to confirm some longstanding theories about atmospheric sputtering. It further enriches our appreciation of how these processes have contributed to the present-day state of Mars.
“Sputtering driven by the solar wind motional electric field.” – Curry et al.
The Role of Ultraviolet Light
Incredibly, the most impressive finding of the study was to underscore the power of ultraviolet light from our sun. It was important in raising the atmospheric sputtering rates during Mars’ early history. In this formative phase, Mars would have undergone atmospheric loss at rates orders of magnitude greater than what is observable in the present day. That dramatic shift would have transformed Earth’s climate and capacity to hold water.
This information adds depth to existing theories surrounding Mars’ past, indicating that atmospheric sputtering was not only a recent phenomenon but has likely influenced the planet’s habitability over millions of years. By understanding these mechanisms, scientists can better assess how Mars transitioned from a potentially habitable environment to the desolate landscape observed today.
Implications for Future Research
The implications of this discovery reach far beyond just understanding Mars’ climate history. It raises exciting new opportunities to study atmospheric dynamics on other worlds, especially on planets that do not have such shielding magnetic fields. What we learn now on Mars will help guide studies of exoplanets and whether they may be capable of supporting life.
Science investigators are continuing to study data from MAVEN and other missions. They hope to discover amazing new insights into the processes of solar wind interaction with planetary atmospheres. That knowledge deepens our understanding of Mars and advances planetary science overall.