A 2023 meteoroid impact on Mars caused dust avalanches, creating new streaks, with most recurring slope lineae forming seasonally from wind, not water.

A meteoroid impact near Apollinaris Mons on Mars in December 2023 triggered dust avalanches, creating over a hundred new streaks captured by the ExoMars Trace Gas Orbiter. Research published in Nature Communications reveals that while most recurring slope lineae (RSL) form seasonally due to wind-driven dust avalanches, less than 0.1% annually result from non-seasonal events like impacts or marsquakes. Over two million RSL features were analyzed using machine learning, showing most streaks occur in five hotspots and fade over years. These findings support the theory that RSL are primarily dry processes, challenging earlier water-based hypotheses and highlighting the role of long-term orbital observations in understanding Mars’ dynamic surface.