Overview
- A Nature Geoscience paper published Wednesday presents models that reproduce the Arsia Mons Elongated Cloud only after adding homogeneous nucleation to account for ice forming without dust.
- The team says winds over the 11–12.5 mile high Arsia Mons create strong gravity waves that lift moist air to about 28 miles altitude and cool it by roughly 30°C in minutes, driving a spike in relative humidity.
- Homogeneous nucleation means water vapor freezes directly into ice particles rather than condensing on dust; the researchers say this process is required in their simulations to make the cloud’s 1,100–1,120 mile tail appear.
- The cloud has been seen in modern and archival imagery, including ESA’s Mars Express and NASA’s Viking 2, but the hypothesis remains provisional because confirming it will need targeted morning observations of Mars’s upper atmosphere.
- If confirmed, the finding would change how scientists model cloud formation on Mars and could prompt new observation campaigns and instrument plans for Mars missions to measure humidity and particle counts aloft.