A comprehensive catalogue of clouds observed on Mars has unveiled the planet’s stunning array of atmospheric phenomena, many of which are unlike anything seen on Earth. Despite its thin atmosphere composed primarily of carbon dioxide, Mars can produce striking cloud formations when conditions are right, New Scientist reported.

Daniela Tirsch and her colleagues at the German Aerospace Center have compiled a “cloud atlas” using images captured by the European Space Agency’s Mars Express probe over two decades to better understand these patterns and their impact on the Martian climate.

Some of the clouds observed resemble their Earthly counterparts, such as gravity wave clouds and cloud streets. These clouds form due to atmospheric disturbances caused by Martian surface features or chaotic currents within the atmosphere. However, Mars’ unique atmospheric conditions give rise to clouds that have no terrestrial analogues.

Elongated dust clouds, for instance, are a distinctive feature of the Martian atmosphere. These clouds can stretch for hundreds of kilometres and have a striking reddish hue due to the vast quantities of Martian dust they contain. Additionally, orographic clouds form as air is forced upward by mountains and volcanoes, sometimes mixing with dust or dust storms to create features that mimic volcanic eruptions.

Twilight clouds, which appear near the horizon as the sun rises or sets on Mars, are particularly intriguing. These clouds can take on a variety of forms, from wispy cirrus-like structures to strange, clustered blobs. Their appearance and behaviour are influenced by a combination of factors, including the angle of sunlight, the composition of the atmosphere, and the presence of dust or other particles.

The diversity of cloud formations observed on Mars highlights the complexity of the planet’s atmospheric dynamics. By studying these clouds, scientists can gain valuable insights into the Martian climate, the circulation of the atmosphere, and the role of dust in shaping the planet’s environment.