Europe's Mars Express orbiter has stared down the throat of the Solar System's largest volcano, Olympus Mons, to produce the best ever images of the giant peak. The images, released on Wednesday, were taken with the orbiter's High Resolution Stereo Camera (HRSC) from a height of 273 kilometres and reveal details as small as 12 metres across.
Geologists "can now get their teeth into how similar the 3-D shapes of lava features are compared to Earth's volcanoes," says Jan-Peter Muller, one of the camera's co-investigators at University College London, UK. Olympus Mons rises 22 kilometres above the surface of Mars, making it nearly three times taller than Mount Everest. It is topped by a three-kilometre-deep caldera, which is the focus of the new images. The overlapping circular pits visible were created after eruptions ceased and the magma within the volcano retreated, causing the peak to cave in. The largest pit occurred first, with the smaller ones sinking later. The concentric fractures also formed as the surface dropped. More images here. Source: New Scientist.
