For decades, millions of dark, linear streaks crisscrossing the Martian surface have baffled scientists. New research finally provides a comprehensive explanation: these features, known as slope streaks, are primarily formed by seasonal wind and dust erosion, not the impacts or seismic activity previously suspected. The study, published November 6 in Nature Communications, analyzed over 2.1 million slope streaks photographed by NASA’s Mars Reconnaissance Orbiter between 2006 and 2024, revealing that less than 0.1% of new streaks originate from meteoroid impacts or marsquakes.
The Mystery of Martian Streaks
Slope streaks appear as dark albedo features on the slopes of Martian terrain. Discovered in the 1970s, they were initially thought to be landslides triggered by melting ice. While landslides do play a role, the new research demonstrates that most streak formation occurs through “dry processes” – meaning no water involvement. The study’s author, Valentin Bickel of the University of Bern, Switzerland, found that the vast majority of streaks are linked to seasonal wind patterns and dust mobilization.
Wind and Dust: The Dominant Force
Bickel’s analysis revealed that slope streaks are clustered in five key regions across Mars. New streaks consistently appear in these areas when seasonal wind speeds exceed a threshold for dust movement. Once this threshold is met, landslides become more likely, creating the visible streaks. This process is similar to how high winds on Mars trigger dust devils – sizable tornadoes of dust that sweep across the planet’s plains.
Why It Took So Long
The mystery persisted for decades partly because streak formation occurs under specific conditions – at sunrise and sunset. These conditions are not easily observed directly, explaining the lack of eyewitness accounts of streak-forming events. The study estimates that approximately 80,000 new streaks form each year on Mars, given the estimated 1.6 million existing streaks. Most streaks likely persist for decades before fading, but long-term data is limited.
Implications for Future Mars Missions
Although slope streaks cover less than 0.1% of the Martian surface, they may be the largest single contributor to atmospheric dust. Understanding their role in the Martian dust cycle is critical for future human colonies, as dust storms pose significant operational and health risks. The research highlights the importance of continued monitoring and analysis of these features to improve predictions and mitigate potential hazards.
The study confirms that wind and dust erosion are the primary drivers of slope streak formation on Mars, resolving a 50-year mystery and providing crucial insights for future exploration
