Free Astronomy Magazine January-February 2018

17 JANUARY-FEBRUARY 2018 SPACE CHRONICLES canic province on Mars, its far-reach- ing fracture system testament to the powerful influence this impressive volcanic province had on the planet. Indeed, the Sirenum Fossae fracture system seen here is thought to be as- sociated with tectonic stresses aris- ing from ancient volcanic activity in the Tharsis region. For example, the graben could either be caused by the planet’s crust stretching apart as a magma chamber bulges the crust above it, or alternatively as the crust collapsed along lines of weakness as T he region outlined by the larger white box indicates the area imaged during Mars Express orbit 16688 on 5 March 2017. [NASA MGS MOLA Science Team, Freie Universitaet Berlin]