Scientists explain 1,100-mile Mars cloud via homogeneous nucleation

Astrophysicist Jorge Hernández Bernal and colleagues, writing in Nature Geoscience, attribute the elongated Arsia Mons cloud (AMEC) on Mars to homogeneous nucleation — water vapor freezing directly into ice without dust particles. The cloud forms daily at sunrise over the 11-mile-high volcano and vanishes within three hours.

• The AMEC cloud stretches about 1,100 miles over the Arsia Mons volcano
• It forms at sunrise and disappears within three hours, complicating observations
• Computer models reproduced its long tail only with dust-free homogeneous nucleation
• Humidity in the cloud's formation zone exceeds Earth's by over 100,000 times