Mars cloud formation involves exotic homogeneous nucleation physics
Scientists using ESA's Mars Express orbiter and meteorological modeling found that Mars's Arsia Mons Elongated Cloud (AMEC) forms through homogeneous nucleation, a rare process where water vapor freezes directly into ice crystals without requiring dust particles as condensation seeds. The research, led by Jorge Hernández-Bernal at LMD/CNRS/Sorbonne Université, showed that the volcano's height combined with Mars's thin atmosphere creates extreme humidity levels exceeding 100,000 times Earth's typical conditions, allowing this theoretically possible but previously unobserved process to occur. The study, published in Nature Geoscience, demonstrates that winds flowing past Arsia Mons trigger powerful waves that lift and cool air parcels by 30 degrees in just 10 minutes, causing the spontaneous freezing.
