One of the problems with interplanetary colonization is that Earth-like worlds are fairly rare (though possibly not as rare as we once thought). In our own solar system, the only other world that comes anywhere close (Mars) is a radiation-blasted desert with only the barest hint of an atmosphere and a surface temperature colder than Antarctica. To get around this problem, you can do one of two things: build an artificial enclosed environment to house the colony, or change the world itself to make it more Earthlike–in other words, terraform it.
The actual science of terraforming is far too complex (not to mention way over my head) to do it justice in this post. Instead, I’ll just point you to the Terraforming Wikipedia page as a starting point and focus on how the concept is used as a story trope.
According to tvtropes and Wikipedia, the term came from a 1942 novella by Jack Williamson titled “Collision Orbit.” The concept of changing the environment of an entire planet actually goes back much further, with H.G. Wells subverting the trope in War of the Worlds (instead of humans terraforming other worlds, the hostile Martians try to xenoform Earth to make it habitable for them). Before the U.S. and U.S.S.R. put probes on the surface of Mars and Venus, it was fairly common for writers to speculate that those planets were able to support human life, at least on a basic, rudimentary level. Once the science showed that that isn’t actually the case, terraforming as a story trope really began to take off.
Today, this trope occurs commonly across all ranges of the Mohs scale. Soft sci-fi stories (such as Firefly) use it as an excuse to have planets that look and feel like Earth. Hard sci-fi stories (such as Red Mars, Green Mars, and Blue Mars) use it as a fundamental premise, or to pose questions like “what is the ultimate destiny of human evolution?” or “how important is it to our species’ survival that we spread out beyond Earth?” Although it’s not something that we as a species have (yet) done, our present science seems to place it well within the range of the plausible, and that means that makes it fair game for any kind of science fiction.
In order to be believable, however, any significant terraforming project requires two things: resources and time. LOTS of time. We’re talking on the order of centuries and millenia here. Because of that, stories that use this trope generally fall into the following categories:
- The terraforming happened a long time ago and is part of the world’s ancient (or near ancient) history.
- The terraforming is on-going and directly impacts almost every element of the world’s culture and setting.
- The terraforming has failed in some way, which may (or may not) make it a key element in the story conflict.
As with generation ships, the scope of this trope spans more than just the interests of a single character–it deals with the ultimate destiny of entire cultures and civilizations. In hard sci-fi stories, the planet that’s being terraformed may actually become more of a character in itself than the individual people who are terraforming it. Unless they have some form of immortality, they have little hope of ever seeing the ultimate end of it.
Of course, that almost makes the project more of a religion to the colonists than a science, with all sorts of interesting philosophical and story implications.
Why is this trope so widespread in science fiction? I can think of a few potential reasons. First, it hits on some of the key issues that lie at the very heart of the genre, such as the ultimate destiny of humanity and the ethical issues surrounding our ability to play God through the wonders of science. Also, it captures the imagination in a way that few other tropes can equal. Because the scope of any terraforming project is so vast, the implications touch on almost every key element of the story, including setting, character, and conflict.
But on an even more fundamental level, it hits on one of the key elements of any fantasy magic system: limitations. We can’t live on an alien world because the conditions are too hostile, but we can’t just wave our hands to make it Earth-like either. We have to undergo a painstaking, laborious process that could unravel at any point and throw everything we’ve worked for into chaos. We have to dedicate our whole lives to the project for dozens of generations before it will ever pay off. There are no shortcuts–none that won’t strain our readers’ suspension of disbelief, anyway. But if it all works out, then we will have created a new Earth–and how is that not magic?
Needless to say, I’m a big fan of this trope. I’ve used it in just about every science fiction story I’ve written, though I probably play with it the most in Star Wanderers. The main character of that story comes from a world where a terraformation project failed, having severe religious implications that drive the whole series. Sacrifice is largely set in orbit around a world that is midway through the terraforming process. Elswhere in the Gaia Nova universe, people build domes just as often to keep humanity from screwing over a terraformed world as they do to provide room to live on one that isn’t. After all this, though, I feel like I’ve only begun to scratch the surface of this trope. You can definitely expect to see it in my work in the future.
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