New photos taken by the European Space Agency's Mars Express spacecraft show that winter on the red planet resembles winter on Earth, at least in some places. These photos not only display the unique topography of an area on Mars known as Hooke Crater, but also show signs of carbon dioxide frost on its surface.
Hooke Crater is located in the southern hemisphere of Mars in an area known as the Argyre basin. The surface there has seen numerous impacts that affected its topographical features throughout the planet's history, creating a series of craters, ridges, mesas and hills. This area, which is about 138 miles wide, is thought to have suffered a major impact around 4 billion years ago. Constant exposure to wind eroded and shaped most of the ridges in the region.
Hooke Crater is littered with buttes, mesas and hills, which are the result of large amounts of water ice melting on the planet's surface. Some of these larger areas may still contain this ice.
Hooke Crater's largest feature is a dune-like mound believed to contain layers of sand and frost. However, smaller dunes are also spread out from this area across the crater. In the Mars Express images, the lower regions of the crater have a thin layer of white frost, most likely made up of carbon dioxide.
"Clearly, this region has been greatly modified by natural forces since the dramatic impacts billions of years ago that formed the Argyre basin and, later, the pair of Hooke craters," says the ESA.
The ESA's Mars Express spacecraft launched in 2003 and reached Mars in 2004. It takes high-resolution images of the surface of the red planet, allowing for topographical and mineralogical mapping of its surface. Radar equipment allows the spacecraft to see just under the surface, for studying Mars' permafrost.
Mars Express was the first planetary mission for the agency. Since its entry into Mars' orbit, Mars Express has made new discoveries about the planet, including finding water ice on Mars' South Polar ice cap, discovering small amounts of methane in Mars' atmosphere, and creating a near-complete topographical map of Mars' entire surface.
