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The presence of tuff cones -- formed by eruption of lava in the presence of water together with other volcanic features indicative of water -- in the Harrat Khaybar suggest that the local climate was much wetter during some periods of volcanic activity. Today, however, the regional climate is hyperarid -- little to no yearly precipitation -- leading to an almost total lack of vegetation.
The possibility of impacts of large meteorites on the thin crust of the early moon accounting for the formation of the hexagonal lunar craters is discussed. Solidified basalts comprising a lunar crust of thickness 10 to 50 km characteristic of the earliest stage in lunar evolution are shown to have a large-scale hexagonal pillar structure, due to the effects of shrinkage. Results of experimental simulations of the propagation in this hexagonal pillar structure of the shock wave generated by the impact of a meteorite of diameter 10 km and mass 10 to the 15th kg on the lunar crust are then presented which demonstrate the pushing away from a central circular shock of pillars resting on a low-friction surface in a hexagonal pattern