Mars this, there are far fewer craters on Mars compared with the Moon, because the atmosphere of Mars provides protection against small meteors and surface modifying processes have erased some craters. Martian craters can have a morphology that suggests the ground became wet after the meteor impacted. The shield volcano Olympus Mons ("Mount Olympus") is an extinct volcano in the vast upland region Tharsis, which contains several other large volcanoes. Olympus Mons is roughly three times the height of Mount Everest, which in comparison stands at just over . It is either the tallest or second-tallest mountain in the Solar System,
Olympus Mons This inhibition of southeasterly basal spreading in Olympus Mons could account for the structural and topographic asymmetry of the mountain. Numerical models of particle dynamics involving lateral differences in friction along the base of Olympus Mons have been shown to reproduce the volcano's present shape and asymmetry fairly well. It has been speculated that the detachment along the weak layers was aided by the presence of high-pressure water in the sediment pore spaces, which would have interesting astrobiological implications. If water-saturated zones still exist in sediments under the volcano, they would likely have been kept warm by a high geothermal