Mars' Odd 1,100 Mile Long Cloud Forms in Mysterious Ways — a New Model May Reveal How
Learn more about the AMEC, a strange, recurring cloud on Mars that has long baffled scientists, until now.
In 2018, Europe's Mars Express satellite detected something peculiar: an unusual water ice cloud near the Arsia Mons volcano on Mars. This cloud, known as the Arsia Mons Elongated Cloud (AMEC), emerges during Mars' spring and summer in the Southern Hemisphere. Growing up to 1,118 miles (1,800 km) long, the AMEC typically appears, expands, and dissipates within a day. Despite numerous attempts to comprehend the cloud's formation, researchers faced challenges until a recent study proposed a new model.
The study, published in Nature Geoscience, revealed that the AMEC might form without the usual "stuff" that clouds on Earth require. Normally, clouds form when moist air cools, leading to water vapor condensing into droplets or ice crystals through heterogeneous nucleation, which involves particles like dust. However, the AMEC appears to form via homogeneous nucleation, where water vapor directly converts into icy cloud particles without any intermediate step.
For this unusual process to occur, the researchers found that the AMEC lies in a unique position where the Arsia Mons volcano and Mars' thin atmosphere intersect. As winds flow past the 12-mile-tall volcano, a powerful wave lifts moist air into the atmosphere quickly. The moist air then cools rapidly, causing a temperature drop of about 30 degrees within 10 minutes.
The spikes in humidity levels then cause the water vapor to freeze into cloud particles, resulting in the AMEC's formation. While the model isn't perfect, the success in simulating the AMEC is significant, given the limited knowledge about Mars' atmosphere compared to Earth's.
Written by urgent.news from Discover Magazine's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
