In the run-up to Christmas, the European Space Agency has published a spectacular new image made by the Mars Express spacecraft. It shows the “winter” landscapes of the Red Planet.
Like our Earth, Mars has polar caps. But despite their external similarities, they have a fundamentally different structure. Our planet’s polar caps are made of water ice. On Mars it is so cold that carbon dioxide is frozen out of the atmosphere at the poles, forming a thin layer of dry ice on the surface. Underneath, there are alternating layers of dust and water ice, serving as a reminder of the distant times when Mars was a watery world.
The landscape captured by Mars Express is located in the planet’s southern hemisphere in a region called Australe Scopuli. The mixture of dry ice and dust forms a bizarre black-and-white pattern. The contrast of light and dark layers is particularly noticeable on the exposed surfaces of hills and valleys. They trace the seasonal polar layering characteristic of this region, formed when layers of ice with varying amounts of dust inside freeze.
With the right amount of imagination, one can imagine that a ski resort could open here in the future. Although, of course, the climatic conditions in this region are much harsher than on Earth: winter temperatures are as low as -125°C.
Any potential Martian skier or tobogganist would also have to consider the dust jet factor. When winter is replaced by spring and then summer, sunlight penetrates through the translucent top layers of dry ice, heating the underlying surface. The ice at the bottom of the layer begins to sublimate, creating pockets of trapped gas.
The pressure gradually builds until at some point the overlying ice suddenly cracks, causing a jet of gas to burst to the surface. These gas fountains carry dark dust, which then falls back to the surface in the form of a fan formed by the direction of the prevailing wind. The length of such a fan can range from tens to hundreds of meters. As the dust settles, it forms characteristic patterns that look similar to spiders, which can often be seen in images of the polar regions of Mars.
Earlier we told you about how ESA visualized a flight over Mars’ ancient canals.
Provided by ESA
