Mars's 2018 planetwide dust storm hints at possible solar influence on its weather

A global dust storm engulfed Mars in June 2018, marking the first time scientists observed a potential link between solar activity and changes in the planet’s lower atmosphere. The event coincided with a solar energetic particle (SEP) event, leading researchers to suspect that the combination of solar radiation and dust storms may influence Martian weather in ways previously unexplored. The study, conducted by a team of astronomers from Lancaster University, the University of Leicester, and the Instituto de Astrofísica de Andalucía-CSIC in Granada, Spain, analyzed five SEP events over several years. Four of these events showed no noticeable impact on the lower atmosphere, but the fifth, one occurring in June 2018—was unique. During this period, a massive dust storm spread across the entire surface of Mars, ultimately leading to the loss of NASA’s Opportunity rover due to power failure caused by reduced solar energy intake. The researchers used data collected by NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft and the European Space Agency’s Trace Gas Orbiter. These instruments allowed them to monitor both the upper and lower atmospheres of Mars, comparing observed temperature patterns against established models from the Mars Climate Database. The analysis revealed a temporary increase in lower-atmospheric temperatures during the June 2018 event, suggesting a possible connection between the solar activity and the weather phenomenon. Lana Williams, a Ph.D. researcher at Lancaster University who led the study, noted that while the team anticipated some level of atmospheric response to the SEP event, the results were surprising. “We expected that these highly energetic particles might have some effect on temperatures in Mars’s lower atmosphere,” she said. “But in four of the five events we studied, we found no clear evidence of heating. The one exception occurred while a global dust storm was expanding across the planet.” The study highlights the complexity of Mars’s atmospheric dynamics. While dust storms are known to naturally heat certain regions by absorbing sunlight, the observed temperature pattern during the June 2018 event did not align with typical dust storm behavior. This discrepancy suggests that additional factors, such as solar activity, may play a role in shaping Martian weather systems. Solar energetic particle events occur when solar flares and coronal mass ejections release high-energy particles into space. Mars, lacking a strong global magnetic field and possessing a thin atmosphere, is more vulnerable to these particles than Earth. Previous research has documented how SEPs can alter the upper atmosphere, producing ionization and disrupting communications, but their influence on the lower atmosphere, where weather processes occur, remains poorly understood. The researchers caution that a single instance of increased temperature does not definitively establish causation. Nevertheless, the findings open new avenues for understanding how solar activity interacts with planetary weather systems. The team plans to continue monitoring future SEP events and their potential impacts on Mars’s climate, aiming to refine models of atmospheric behavior and improve predictions of weather patterns on the Red Planet. As the study is being presented at the Royal Astronomical Society’s National Astronomy Meeting in Birmingham, the implications of the research extend beyond academic interest. Understanding the interplay between solar activity and Martian weather could aid in planning future missions and improving the accuracy of climate models for the planet. The June 2018 event stands as a rare and valuable case study in the ongoing exploration of Mars’s dynamic atmospheric environment.