I just finished Kim Stanley Robinson‘s 2132 so space and Mars is already on my mind.  Robinson is probably best known for his Blue/Green/Red Mars trilogy.  All of those books touch on terraforming Mars, the concept that we might alter the atmosphere — the entire planetary system — of Mars such that ultimately it could be inhabitable by humans.  Here’s a video on the idea from Michio Kaku, a Professor of Theoretical Physics at CUNY and Science-Person-On-TeeVee:

But today, we haven’t even sent a human to Mars.  Still in my lifetime the most exciting part of the space program has probably been the launch of the robot explorers of Mars.  And we’re less than a month away from the landing of the latest robot rover sent to Mars: Curiosity:

Both threads of thought are fascinating to me — the actual progress of learning more about Mars in the here and now; with the careful exploration of a dead planet’s geological history and the still hypothetical pondering of just how hard would it be to turn Mars into a version of Earth.  And to realize that these conflicting drives: to explore and learn about Mars and to turn Mars into something else — these drives could not fully co-exist if we had the technology to pursue both.

Everything I’ve read seems to agree that terraforming Mars would require three changes: warming up the planet, building up the atmosphere, and starting up a magnetic field.  In 2312, although a ton of detail is given over to it, terraforming of Mars seemed to have been accomplished by slamming asteroids into it, spinning up the planet.