NASA Has Just Released Breathtaking New Photos of Mars And They Are Marvellous
Take the image above for example, a newly released photo of well-speckled dunes in Mars' north polar region. In this image, taken during the northern spring season, the dunes and ground are still covered in seasonal frost. The speckled appearance is due to the warming of the area — as the carbon dioxide frost and ice on the dunes warms, small areas warm and sublimate (turn from solid to gas) faster, creating small jets that expose/deposit dark sand and dust onto the surface, writes Serina Diniega on the HiRISE website. Notice that there are no spots on the ground between the dunes — that is because the ground stays more uniformly cold, unlike the darker dune sand.