The idea of terraforming nearby planets (or more distant ones) is well established in modern culture. Moreso than I knew. The linked Wikipedia article on "Terraforming in Popular Culture" lists science fiction, movies, and video games that make reference to the idea. Some of the most important pioneering stories I was familiar with, including Robert Heinlein's Farmer in the Sky and Isaac Asimov's The Martian Way (both of which I'd read). I had also heard about Kim Stanley Robinson's Martian Trilogy (Red Mars, Green Mars, and Blue Mars). But I didn't know that there are at least 15 science fiction stories that feature terraforming, as well as at least 20 TV and movie references to it and over 30 video games in which terraforming is either a goal or a plot element.
Those used to easy travel to other worlds in a lot of popular science fiction (which are often really a part of the sub-genre "Space Opera"), such as in both Star Wars and Star Trek, may not see why human beings would bother to take the effort to make other planets in our Solar System inhabitable. Why? Why not just stick with good old Planet Earth? Or if we are to leave Earth, why not for other worlds around other stars that are virtually the same as Earth already?
The answer lies in the fact that there is no known way to do warp drive, hyper drive, jump to light speed, make wormholes, or take a jaunt in the TARDIS. If we are going to talk about what human beings are really going to do based on science we understand and therefore what we really are going to accomplish, star travel would seem to be limited to flying the way we know how to fly. Which means by traveling fast as we possibly can in normal space.
"As fast as we possibly can" is actually a lot harder to attain than you might think, as I discussed in a post on "Nanite Space Weapons" from several years back. Suffice it to say takes roughly as much antimatter in tonnage as the weight of a spacecraft to get up near to light speed--which is still awfully slow for any voyages beyond the closest of stars. And please note that flying anywhere near the speed of light would be deadly to human life as I noted in my post on "Interstellar Fortresses and Starship Combat." Doing more than that may become possible based on yet-future discoveries. But the distances involved and forces required are truly mind-boggling.
So--realistic science fiction travel to the stars would have say it would take generations to get there. It's true that sci fi writers don't have to stick to realism. But our travel situation in the Solar System is quite different from interstellar travel. Relatively well-understood things like fusion-reactor driven spaceships or anti-matter driven ships or even good fission drives (and more) would effectively open up the Solar System to regular and easy travel, especially for everything inside, say, the orbit of Jupiter. Or even as far out as Saturn. (Uranus, Neptune, and Pluto and beyond likely will always be long hauls...)
So since travel to Mercury, Venus, the moon, Mars, the asteroids, and Jupiter's moons is not unrealistic at all, it becomes pretty clear that transforming all of these places so that human beings could live there constitutes a really good idea. Even though transforming an entire planet or moon to make it Earthlike is likely to take hundreds of years at best.
This focus on terraforming forms the backdrop of the Medieval Mars stories I've been recently working on. Though terraforming would also be in the backdrop for other story ideas I've had (such as the Kaiser's Interplanetary Cold War). (The world map of my fictional terraformed Medieval Mars is below:)
Terraforming in short makes sense. Therefore science fiction can't really afford to ignore it. Science fiction writers who read this post should be thinking about it. :)
For my next post, I'll look at the HOW of terraforming. How is it an uninhabited world could be made livable? Until then...