With more than 6.5 billion people living on Earth and that number increasing all the time, our planet is quickly becoming overcrowded. So it seems reasonable, notwithstanding the monstrous technical challenges it would present, that we might one day start to look beyond our planet for future housing solutions. But why would we consider Mars? True, it's relatively nearby, galactically speaking; we know a lot about it already; it at least used to be a bit more like us; and it even has two moons (Phobos and Deimos) to hit us in the eyes like big pizza pies -- but Mars? Who knows? Perhaps inhabiting the red planet might be a more realistic housing option than it might seem at first blush. Perhaps one day we'll have no choice but to pack up and leave the planet.
But let's not kid ourselves. Thus far, nothing's changed about Mars. It's still the same inhospitable, rocky, barren place it was yesterday, last week or a thousand years ago. It's quite cold, has a terribly thin atmosphere, has essentially no magnetic field and provides no oceans in which to jet-ski. If we do want to live on Mars, it's not exactly rolling out the welcome mat.
So, clearly, terraforming Mars would be an incredibly daunting task. In order to recreate the planet as a kind of second Earth, we would need to address its atmospheric shortcomings and warm its frozen surface. Scientists, ever on the task, have proposed a number of schemes to induce a Martian greenhouse effect, ranging from the use of oxygen factories to crashing an asteroid into one of its poles. The idea in either case being, of course, that in time the greenhouse effect would thicken the atmosphere and warm the planet, bringing it a little closer to the kind of habitable conditions present on the third rock from the sun. We'd also need to work out the most efficient homes to build; the best way to feed ourselves and a host of other questions. It also wouldn't hurt if we improved our space travel technology so we could shuttle between Earth and Mars a bit more easily during all of this terraforming work. Daunting, indeed.
Why do we need rockets?
Answered by Jacob Silverman and Discovery Channel
How should NASA change its mission?
Answered by Peter H. Diamandis and Christopher J. Ferguson
Are there any other planets out there like Earth?
Answered by James L. Green and Science Channel