A Swiss-cheese Martian landscape
The low summer Sun highlights subtle features of the Martian landscape.
In this photo by NASA’s Mars Reconnaissance Orbiter, it is summer in the red planet’s southern hemisphere. The Sun hangs low in the Martian sky and strikes the ground at an oblique angle, throwing small variations in topography into sharp relief.
The lighter grey areas are the residual icecap of frozen carbon dioxide, now pocked with growing holes to produce what is sometimes called “Swiss cheese terrain”. The deeper circular feature at the top right of the image may be a crater caused by asteroid impact or it may be a pit resulting from the ground collapsing.