Winter in Argyre

19 September 2014 - Over billions of years, the southern uplands of Mars have been pockmarked by numerous impact features, which are often so closely packed that they overlap. One such feature is Hooke crater, shown in this frost-tinged scene, imaged by ESA's Mars Express during winter in the southern hemisphere. Hooke crater is located near the northern edge of the 1800 km-wide Argyre basin - one of the most impressive impact structures on Mars, excavated in a giant collision about 4 billion years ago. Sitting in a flat part of the basin known as Argyre Planitia, Hooke crater has a diameter of 138 km and a maximum depth of about 2.4 km. It is named after the English physicist and astronomer Robert Hooke (1635-1703). Hooke crater comprises two different impact structures, with a smaller impactor blasting a depression off-centre in the floor of a larger, pre-existing crater. The newer crater in the centre is filled with a large mound topped by a dark dune field.