Geology of Mars time. This section introduces several of the larger physiographic regions of Mars. Together, these regions illustrate how geologic processes involving volcanism, tectonism, water, ice, and impacts have shaped the planet on a global scale. The northern and southern hemispheres of Mars are strikingly different from each other in topography and physiography. This dichotomy is a fundamental global geologic feature of the planet. Simply stated, the northern part of the planet is an enormous topographic depression. About one-third of the planet’s surface (mostly in the northern hemisphere) lies 3–6 km lower in elevation than the southern two-thirds. This is a first-order
Exploration of Mars one of the proponents of such missions. Various asteroids, moons, and places on Mars can be mined while crops are initially being planted. This method will save lives on Earth, add potentially trillions of dollars to the world economy annually, and provide a stable colony on Mars. Some have also stated that persons should stay on Earth, but get food and resources from Mars and surrounding asteroids, moons, greenhouses in space and other structures. Some critics contend unmanned robots can perform better than humans at a fraction of the expense. If life exists on Mars, a human mission could contaminate