What exotic microphysical process explains the Arsia Mons Elongated Cloud on Mars?

Lens adapted to this topic: Conventional cloud physics and remaining uncertainty

A cautious interpretation emphasizes that the cloud is still an orographic phenomenon and that homogeneous nucleation is inferred from simulations, not directly measured in the Martian atmosphere. Conventional mountain-wave dynamics remain part of the explanation, while the proposed nucleation mechanism may be a model-dependent account of how ice particles initially form.

• The cloud’s large-scale setting remains consistent with an orographic cloud produced as winds flow over Arsia Mons’s topography.
• Earlier modeling reproduced a cold, highly supersaturated region near the cloud’s origin but failed to reproduce the full tail, showing that dynamics and microphysics are distinct issues.
• Homogeneous nucleation has generally been considered unlikely in Martian clouds because aerosols should normally provide surfaces for heterogeneous nucleation and limit supersaturation.

Featured sourceHomogeneous nucleation on Mars. An unexpected process that deciphers mysterious elongated cloudsexa.ai4 sourcesView sources