Archive · 15 Sep 2025
Scientists Discover Cause of Recurring Martian Cloud Formation
Imagine a giant cloud that appears on Mars every year like clockwork.
Scientists have been trying to figure out why!
They found that it's made of ice crystals forming in a process called homogeneous nucleation.
This happens because of high water vapor content interacting with the slopes of a huge, old volcano.
The cloud appears in the morning, stretching for miles, and disappears in the late morning because of sunlight and changing winds.
This helps scientists understand how weather works on Mars and where water moves around, which could be important for future space missions and finding if life could exist there.
A ribbon-like cloud, the Arsia Mons Elongated Cloud (AMEC), appears annually on Mars.
The cloud forms on the western side of the Arsia Mons volcano.
The cloud is made of ice crystals formed by water vapor condensation.
The process is triggered during the southern summer solstice season.
Scientists used data from the Mars Express orbiter to study the cloud.
- Who
- Scientists using data from the European Space Agency's Mars Express orbiter.
- What
- Have discovered how a large, recurring cloud forms on Mars.
- When
- Every year during the southern summer solstice season.
- Where
- On Mars, specifically on the western side of the Arsia Mons volcano.
- Why
- To understand Martian meteorology and the movement of water vapor on the planet.
- Feature Name
- Arsia Mons Elongated Cloud (AMEC)
- Location
- Western side of Arsia Mons volcano on Mars
- Length
- Up to 1,800 kilometers
- Formation Process
- Water vapor condenses into ice crystals
- Trigger
- Southern summer solstice season
- Duration
- Daily for nearly three months
- Key Factor
- Homogeneous nucleation of ice particles