howardpark/space exploration

Most discussions of extraterrestrial colonization focus on technology, i.e. will we ever have the ability to colonize other planets? To me, the answer seems obvious: The United States (let alone the entire world) has most of the required technology already, and the rest is easily within reach, at least for the colonization of a nearby planet.

The real question is: Will humans ever have a reason to colonize other planets? People who once imagined that there would be mining colonies on the Moon or Mars have by now come to the realization that their assumptions were faulty. Even if the Moon were made of solid gold, the cost of transporting materials to and from this orbiting gold mine would far exceed any profit to be derived from such an enterprise. (Keep in mind that the Law of Supply and Demand would drive the price of gold down--the more gold there was up there, the less it would be worth! Also, an influx of precious commodities without an increase in productive capacity would lead to runaway inflation. This is how New World gold ended up destroying the economies of Spain and Portugal.)

So why would humans ever go to the enormous expense of colonizing other planets? The idea that we would "run out of room" on Planet Earth is as half-baked as the idea that we could profitably mine the Moon. Population scientists predict that the Earth's human population will level off sometime this century between 10 and 11 billion. The reasons for this leveling-off are complex but basically have to do with industrialization and the more secure life expectancies that accompany it. So the situation imagined in Star Trek (original season 3, episode 72: "The Mark of Gideon"), in which an entire planet is covered with living human bodies, is nonsense. (In that episode, the people of Planet Gideon were packed shoulder-to-shoulder at all times. To achieve a similar density on Earth, say 1 person per square meter of dry land, the population would have to reach 149,000,000,000,000, or about 25,000 times more than it is today.)

Another commonly cited rationale for extraterrestrial colonization is the notion that "human beings have always expanded into uninhabited areas." Even if this were true (large areas of our own planet have no permanent human settlements), it doesn't necessarily mean we will expand off-world. Uninhabited areas on Earth are fundamentally different from uninhabited areas on other planets. Besides the obvious physical differences, there is also the fact that our evolution adapted us to conditions that are specific to this particular planet, so patterns of human colonization on Earth imply nothing about human colonization elsewhere.

At first glance, global climate change seems to provide a more reasonable justification for colonizing other planets. But even if humans do nothing to limit their impact on the environment (i.e. we keep spewing carbon to our heart's content), we would at worst end up turning Earth into an "Earth-like" planet, with plenty of water (in the form of vapor), surface temperatures well within our tolerance, and exactly 1.0g gravity. If we were looking for a planet to colonize and found one meeting these criteria, its discoverers would celebrate wildly. So why travel millions of miles and spend trillions of dollars to find Earth-like conditions when we have them right here? To put it bluntly, even if we devastate our planet, it will still be a better place for humans to live than almost any other conceivable place.

Since there seems to be no rational motivation to colonize other planets, how about irrational motivations, such as religious belief? There is obviously no gainsaying faith, so this scenario can't be ruled out. Optimistic atheists may hope that, in a highly scientific/technological society, religion would go the way of the dodo bird, but psychologists have shown that superstition is an irreducible feature of human cognition. Since religious thought is here to stay, this rationale for extraterrestrial colonization at least seems less unlikely than the others.