Science · 2026-10-26 · Morning briefing

Exotic physics may explain 1,000-mile cloud on Mars

Researchers believe they have solved the mystery of a vast cloud on Mars that stretches for over 1,000 miles. A new study in Nature Geoscience proposes that the Arsia Mons Elongated Cloud, first observed in 2018, forms through a process called homogeneous nucleation. This phenomenon, until now purely theoretical and never directly observed in nature, involves water vapour turning directly into ice crystals without needing dust or debris as a seed.

The model requires a specific set of extreme conditions. Wind hitting the 65,000-foot-tall Arsia Mons volcano creates a powerful atmospheric wave, launching moist air upwards. This triggers a sharp temperature drop of 30° Celsius within just 10 minutes, allowing ice crystals to form spontaneously in Mars' atmosphere.

The study's lead author, from Paris’ Sorbonne Université, described the process as akin to condensation appearing in the middle of a room instead of on a window. For the model to work, the simulation required a relative humidity more than 100,000 times greater than any value ever measured on Earth.

Summary written by Cup of News with AI from the sources below. Check the originals for the full story.

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• The ‘Exotic Physics’ Behind a Mysterious 1,000-Mile Cloud on Mars
• Giant cloud that forms and vanishes on Mars every day obeys 'exotic physics' never seen on Earth
• Weirdest cloud on Mars formed via ‘exotic physics’
• Extraordinary giant cloud on Mars likely caused by “exotic physics”

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