For the first time, scientists have directly observed atmospheric sputtering on Mars, a process driven by solar wind ions that may significantly contribute to the planet’s atmospheric and water loss. Utilizing data from NASA’s MAVEN spacecraft, researchers found variations in argon densities at altitudes above 350 kilometers, correlating with the orientation of the solar wind electric field, indicating active sputtering. These findings, published in Science Advances, also suggest conditions on early Mars were influenced by more frequent solar storm activity.