I don’t quite understand why some people are getting all worked up about the news of a possibly human-hospitable planet 20.4 light years away in Gliese 581.
First, we have a human hospitable planet right here that we’ve barely even begun to use. In a post last September, I outlined how the Earth could easily hold 100 billion people, if not more, by colonizing the deserts and highlands. I didn’t even talk about the oceans, polar regions, underground, or low Earth orbit. To those desperate to get off the planet post haste, I ask: where’s your creativity? Do you realize that we could hollow out regions the size of cities underground, reroute sunlight from the surface down into them, and have a perfectly nice living environment, with none of the inconveniences of outer space such as: lack of organic chemicals, ice cold temperature, ionizing cosmic rays, lack of gravity, lack of water, deadly vacuum, etc? If living underground isn’t your cup of tea, then there is the possibility of ocean colonies, powered by the temperature differential from the deep ocean and the surface, or polar domed colonies, or airship-supplied mountain colonies, or… really, the sky’s the limit, and by sky, I mean space habitats at an altitude of 200km.
Second, even if we did need to leave the Earth, there is a tremendous amount of raw materials for space colonies right next door in the form of carbonaceous asteroids, which make up about 75% of known asteroids. The asteroid belt contains about a million asteroids of 1km diameter, and a great big planetoid (Ceres) about 1000km in diameter, all there for the taking. Some of these asteroids wouldn’t even need to be reprocessed entirely, but could be turned into viable colonies simply by hollowing them out, pumping them full of oxygen, and getting them spinning. The rock is a natural cosmic ray shield. Through exploitation of the resources of our Solar System in this way, we could create colonies for billions of billions of people, if not more.
Third, I submit that we should think carefully before sending off colonists to far-away places without ensuring that they’re capable of protecting the fundamental freedoms of their citizens, and not degenerating into the primitive tribes that humans seem automatically programmed to create in the absence of a checks-and-balances infrastructure. How are we going to make sure that they don’t accidentally create a Blight that the home system is then helpless to deal with? With the matter-energy resources of an entire star system, it would be a Class 1 hassle for us to come up with defenses against a malevolent entity of that category. Even the possibility of such difficulties may make it undesirable for us to expand too fast too soon.