Take a look at this stunning image by the HiRISE camera (on the Mars Reconnaissaince Orbiter) of the South Pole of Mars, where carbon dioxide freezes into an ice cap a few metres thick. The patterns you can see here are the walls of pits which are covered in ice in the winter but have become revealed in the late summer as the increased temperature causes the frost on them to sublimate (turn into gas).
A note about colour here: the wavelengths at which this camera operates are not comparable with those of the human eye and the image has been processed using ‘enhanced colour’. The different colours indicate different types of surfaces and reflectivity rather than the actual colours that we might see.
A note about Mars exploration missions: to date there have been 26 successful missions, and currently , there are two operational missions on its surface (the Curiosity rover and the Insight lander) and six data-collection satellites orbiting the planet (Mars Odyssey, Mars Express, Mars Reconnaisssance Orbiter, Mangalyaan, Maven, and Exomars).
Image credits:
- HiRISE, MRO, LPL (U. Arizona), NASA https://apod.nasa.gov/apod/ap110926.html
- NASA/JPL/University of Arizona https://hirise.lpl.arizona.edu/ESP_026626_1885
- HiRISE, MRO, LPL (U. Arizona), NASA https://apod.nasa.gov/apod/ap180505.html
Find out more:
https://www.uahirise.org/epo/about/
https://www.nature.com/articles/s41561-019-0323-9