A recent batch of images taken by NASA and the European Space Agency show what appears to be a snowy landscape on Mars, but experts say it’s actually carbon dioxide ice with dust layers.
The images were captured in June 2022 by the German-built High Resolution Stereo Camera (HRSC) on the ESA’s Mars Express orbiter, and September 2022 by NASA’s Mars Reconnaissance Orbiter using its High-Resolution Imaging Science Experiment (HiRISE) camera.
However, scientists say the “snow” is not snow at all. Instead, it’s carbon dioxide ice that forms a thick layer in the Australe Scopuli region of Mars near the planet’s south pole. This ice is around 26 feet thick and remains year-round.
The darker areas in the images are layers of dust that have fallen on top of the ice. A seasonal process brings some of this dust to the surface, creating a swirling pattern.
When sunlight warms the carbon dioxide ice in the summer, it causes pockets of trapped gas to form within the ice. As the pressure builds up, tiny gas eruptions occur, spewing dark dust into the air. The wind carries the dust back to the surface, forming these beautiful patterns.
Despite the cold temperatures on Mars, which range from -193°F (-125°C), the images may look like a festive winter scene. However, they are actually a dynamic summer scene where gas jets create swirling patterns on the Martian surface.
Source: https://www.yahoo.com/news/mars-orbiters-witness-winter-wonderland-170000432.html