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
Mars in culture in film. The theme of a Martian colony that fights for independence from Earth is a major plot element in the novels of Greg Bear as well as the movie "Total Recall" (based on a short story by Philip K. Dick) and the television series "Babylon 5". Some video games also use this element, including "Red Faction" and the "Zone of the Enders" series. Mars (and its moons) were also the setting for the popular "Doom" video game franchise and the later "Martian Gothic". Mars in culture Mars in culture is about the planet Mars in culture. For example, the