"THEY change their climate, not their soul, who rush across the sea," says Horace, who was obviously no enthusiast for the package holiday. But future generations who might wish to rush a little further for example, to the planet Mars will need to change their climate in a much more literal sense. Mars will need to be "terraformed" before becoming suitable for human habitation.
As we know from the recent brouhaha about the meteorite, Mars is a frozen arid waste, something akin to the most desolate regions of our own Antartica. Its tenuous atmosphere is so thin as to be hardly there at all. Water in its liquid phase does not exist, and even in solid form it is concentrated in the polar ice caps and the temperature seldom rises above 30 below zero. The process of terraforming would consist of pushing Mars on an accelerated evolutionary path, so in a century or two it might be more amenable to human life.
The first task, and indeed the hardest, would be to raise the temperature. One way in which this might be done would be to build chemical factories on the planet that would pump greenhouse gases into its atmosphere to trap the solar heat. All the ingredients required are already present the Martian rock, all that is necessary is to supply the energy needed to release them, possibly by means of nuclear reactors.
As the greenhouse effects takes hold, and the temperature of the planet gradually increases the permafrost would melt, carbon dioxide, nitrogen and water vapour would seep from the Martian crust in ever increasing quantities, and eventually a hydrological cycle would become established. The colour of the sky would change from pink to blue, and after several hundred years, as the atmosphere gradually becomes thicker, the barometric pressure might rise to 500 mb, about half that to which we are accustomed here on Earth. Ultimately the Martian continents would be divided by small oceans, carbonated but not salty, for the first time in more than 3000 million years.
The next step would be to provide oxygen. At first some could be liberated by artificial heat from the iron oxide in which Mars is rich, and then the process could be augmented by introducing primitive, perhaps genetically altered, forms of vegetation. Finally, perhaps 500 years from now, some honorary Martian citizen may be able to remove his or her space helmet out of doors for the first time: "O, brave new world that has such people in it."