It’s starting to look like Christmas on Mars. The otherworldly landscape is mostly a distinct red hue, but recent images show unusual frosty features that have turned the Red Planet’s south pole white.
The European Space Agency’s (ESA) Mars Express orbiter has captured stunning views of a winter wonderland on Mars, but this is no ordinary snowfall. According to ESA, the south pole of Mars is covered with layers of ice and dust made of carbon dioxide, which creates a mesmerizing picture in the southern region of the planet, called Austral Scopuli.
During the winter season on Mars, the temperature drops to -190 degrees Fahrenheit (-123 degrees Celsius). Despite the cold, no more than a few feet of snow falls on Mars. Unlike snow on Earth, Martian snow is of two types: water ice and carbon dioxide, or dry ice. On the one hand, water ice turns into gas before it even touches the surface, due to the planet’s rarefied atmosphere; dry ice, on the other hand, reaches the surface.
Although it looks like a winter wonderland, the images were taken in June, when it was almost summer at the south pole of Mars. According to an ESA press release, the warm sunlight is causing the seasonal layers of ice to begin to recede, as seen on the left side of the image, where dark spots appear.
As sunlight breaks through the translucent upper layers of dry ice, the ice below sublimates – turning directly from solid to vapor – and creates pockets of trapped gas. The pressure builds until the layers of ice above begin to crack, sending jets of gas bursting through the surface, carrying dark dust from below. Once it breaks through, the dust falls back to the surface as a wind-driven fan.
In the above image of the seasonal ice caps of Ostrahl Scopuli, layers of ice and dust overlap in a swirling dream on the Martian surface. The image was captured by a high-resolution stereo camera on Mars Express, which allowed the topography of the landscape to be derived from a digital elevation model. The image provides a closer look at the fan-shaped pattern created by dust explosions that form the boundaries between layered sediments.
ESA’s Mars Express spacecraft was launched in 2003 and has been providing fascinating images of the Martian landscape for more than 20 years. The spacecraft has compiled the most complete map of the chemical composition of the Mars atmosphere, studied the planet’s satellites Phobos and Deimos in detail, and traced the history of water on Mars, according to ESA. The mission also carried the Beagle 2 lander, but it was lost upon arrival and has never conducted scientific operations on the Red (or, apparently, White) Planet.
