Mars collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement. Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from wide and they are estimated to be at least deep. Because light does not reach the floor of most
Colonization of Mars of life forms, including humans, to survive unaided on Mars's surface. Some ideas of possible technologies that may be able to contribute to the actual terraforming of Mars have been conjectured, but none would be able to bring the entire planet into the Earth-like science fiction habitat pictured. Mars lacks enough gravity to hold on to any kind of substantial atmosphere, which in turn means that the planet will remain cold and cloudless, and the extremely scarce surface water frozen. Mars has no global magnetosphere as Earth does. Combined with a thin atmosphere, this permits a significant amount of ionizing