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
A Beautiful Planet does not have a planetary magnetic field. Consequently, "its atmosphere was ripped away from the planet by the solar wind. If you could stand on Mars today, you would find a landscape of lifeless desolation; very cold, and very dry." One of the current challenges in maintaining Earth's planetary "life support system" is global warming. The film shows how Earth's warming climate is causing the Greenland ice sheet to melt, and drives the point home by showing the Jakobshavn Glacier calving an incredibly large number of icebergs in relatively rapid succession as the end of this flowing river of ice