Twin Martian volcanoes in a cratered landscape

(Image: ESA/DLR/FU Berlin (G. Neukum))

Rising above a crater-studded landscape, two Martian volcanoes sit side by side in the red planet's northern hemisphere.

This newly released image from the European Space Agency's Mars Express orbiter maps contrasting elevations in the region, from the elongated Rahe crater in violet up to the grey summit of the higher volcano Ceraunius Tholus, which rises 5.5 kilometres high and spans 130 kilometres across, dwarfing its neighbour Uranius Tholus.

The smooth floor of the caldera at the summit of Ceraunius Tholus suggests that it may once have held a lake when Mars had a denser atmosphere. Alternatively, the caldera could be the result of ice that formed beneath the topsoil and then melted, undermining the surface.

Mars is also home to the largest known volcano in our solar system, the 22 kilometre-high Olympus Mons. Mars Express provided detailed shots of the giant volcano in 2004.