Climate of Mars cold while those in the North are short and warm. It is now thought that ice accumulated when Mars' orbital tilt was very different from what it is now. (The axis the planet spins on has considerable "wobble," meaning its angle changes over time.) A few million years ago, the tilt of the axis of Mars was 45 degrees instead of its present 25 degrees. Its tilt, also called obliquity, varies greatly because its two tiny moons cannot stabilize it like our moon. Many features on Mars, especially in the Ismenius Lacus quadrangle, are thought to contain large amounts of
The Case for Mars to silver which have not been subjected to millennia of human scavenging and may be sold on Earth for profit. Secondly, the concentration of deuterium – a possible fuel for commercial nuclear fusion – is five times greater on Mars. Humans emigrating to Mars thus have an assured industry and the planet will be a magnet for settlers as wage costs will be high. The book asserts that “the labor shortage that will prevail on Mars will drive Martian civilization toward both technological and social advances.” While detailing the exploration and colonization, "The Case for Mars" also addresses a number