This beautiful view from ESA’s Mars Express stretches from the bright, cloud-covered north pole of Mars to the contrasting hues of the northern hemisphere and the cratered terrain in the south.
Mars Express has been orbiting Mars since 2003. The spacecraft has sent back myriad breathtaking images of our planetary neighbour in the past decade and a half, captured by the probe’s on-board High Resolution Stereo Camera – and this image is no different.
The spacecraft imaged this slice across the planet’s surface in June 2019, when the camera took several global views. Visible at the top of the frame is Mars’ ethereal north pole: this is permanently covered by a cap of frozen water and carbon dioxide, which thickens in the northern martian winter and thins in the summer.
The northern polar cap is seen here encircled by bright, eye-catching clouds, tendrils of which snake downwards from the polar region to obscure some of the planet’s northern hemisphere. As this image shows, this patch of Mars is a mix of different tones and colours – a reflection of the different chemical and physical characteristics of the material that makes up the surface. Mars’ two hemispheres are very different in a number of ways.
Most notably, the northern hemisphere sits several kilometres lower than the southern, and the two are separated by a distinctive, rugged boundary formed of canyons, cliffs and scarps, fractures, valleys, flat-topped mounds known as mesas, and many other features. The northern hemisphere is also characterised by low-lying plains that are largely unmarked by impact craters and thus thought to be relatively young, while the southern hemisphere is ancient, showing signs of intense cratering.
