Hope captures first global image of nighttime clouds on Mars

The Hope probe, launched by the United Arab Emirates and in Martian orbit since 2021, has captured the first complete image of nighttime clouds on Mars. These formations, composed of tiny water ice crystals, play an important role in the Red Planet's climate, despite its thin, dry atmosphere.

Until now, most studies have relied on daytime observations, leaving a void regarding cloud evolution during the rest of the Martian day. Hope's elliptical, low-inclination orbit allowed scientists to observe the atmosphere at any time, at almost all latitudes and longitudes.

The analysis, led by Samuel A. Atwood of the University of Maryland Baltimore, used data from the Mars Infrared Spectrometer for nearly two Martian years. It found that nighttime clouds are typically denser than daytime clouds, with peak cloudiness at dawn and dusk, and a minimum at midday.

During the cold season, the thickest clouds were concentrated near the equator shortly after sunrise, while in the afternoon they became more widely distributed at low latitudes. In the mornings, they were most prominent in the Tharsis volcanic region.

These findings, published in the Journal of Geophysical Research: Planets , offer new clues for refining Martian climate models and better understanding its atmospheric dynamics.