Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Britannica Sources used in this answer

What causes the seasonal color changes seen on Mars?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Mars
Mars An especially serene view of Mars (Tharsis side), a composite of images taken by the Mars Global Surveyor spacecraft in April 1999. The northern polar cap and encircling dark dune field of Vastitas Borealis are visible at the top of the globe. White water-ice clouds surround the most prominent volcanic peaks, including Olympus Mons near the western limb, Alba Patera to its northeast, and the line of Tharsis volcanoes to the southeast. East of the Tharsis rise can be seen the enormous near-equatorial gash that marks the canyon system Valles Marineris.

The seasonal color changes observed on Mars are primarily driven by the dynamic behavior of its polar regions and the occurrence of dust storms.

As the seasons progress, the Martian polar caps undergo significant growth and shrinkage. During fall and winter, carbon dioxide from the atmosphere freezes and deposits at the poles, forming seasonal caps that recede during the spring and summer. These changes in the extent of the polar caps alter the surface albedo, or reflectivity, of the planet's poles.123

Additionally, dust storms play a major role in changing the appearance of the Martian surface. These storms are most frequent during the southern spring and summer. When they occur, large quantities of dust are lofted into the atmosphere, which can obscure the planet's surface and alter its overall color and brightness. While the planet's characteristic reddish hue is caused by iron oxide in its surface dust and rocks, these atmospheric and polar processes create the observable seasonal variations.425