What is out of this world coming to? Stephen Hawking has brought us a remarkably better understanding of deep space over the years. But I feel that his recurring opinion about the necessity to populate the Moon and Mars is preposterous. He had previously proposed this same standpoint almost five years ago, just a month after the September 11th disaster. What's my big beef about all this? I can't see colonies in space easily becoming self-sustaining. It makes for good science fiction, but is incredibly impractical.
We have such a unique and rich assortment of biodiversity here on this beautiful balanced blue planet that has so far proven impossible for humans to duplicate artificially. For instance, let's analyze the largest attempt so far: the 200 million dollar Biosphere 2 project done in Arizona. Conducting such an experiment on Earth means much lower cost compared with launching a microcosm out in space, but aside from proximity what about the other distinct advantages that Biosphere 2 had? Because it was on Earth it had proper temperatures, pre-filtered sunlight, a natural amount of gravity, and a shielding of harmful radiation. That's quite a bit of a head-start. Still that capsule failed both times the experiment was attempted. We have no laurels to rest on in our attempts to create a self-sustaining habitat for thousands. So much miraculous adaptation has already occurred to get us to this point in the Earth's history... Adaptation that we are incapable of replicating over the (relatively) extremely short timeframe of the decades it would take to construct a new habitat on a desolate moon or planet. Those places have incredibly more variables to deal with.
If we do succeed in briefly getting an outpost set up somewhere then there will need to be lots of tweaking in order to try to get it right. Lots of initial dependence from earth on oxygen, water, solar films, or who knows what. Just like unexpectedly the 6 year old concrete at Biosphere was still taking in too much CO2 during the first trial run from 1991 to 1993, we will have similar upsets in any man-made ecosystem. Stuff that tips the scales way too far to easily compensate.
Why do I bring this up now? The Swedes are actually thinking of making an attempt. Even though I'm impressed with the engineering of the Volvo I currently drive and Saab's success with aircraft, what history do the Swedes really have with any space program? They will be hard-pressed to engineer and manufacture an environment on the moon to sustain human life!
The moon or Mars as a vacation destination? Maybe. As a long-term habitat? No. Bottom line: we might as well dig in our heels and enjoy Earth for the abundant environment it provides, and not try to change some God-forsaken rock hanging in another part of the solar system to fill that role. Earth is large enough to have changed slowly enough so that all current species are very well-adapted to it. It also offers gobs of resources that will still persist even through all three major doomsday scenarios that Hawking fears: extreme nuclear disaster, rapid global warming, or the outbreak of a rogue superbug.
I'd like to wrap this post pondering the history of Mars. From evidence recently obtained from the Spririt and Opportunity rovers, apparently Mars used to have a substantial ocean. There is probability that its atmosphere was similar to what Earth's is today, and I find it likely that it once harbored at least simple forms of life back when our sun was a much younger star. Back then I expect it would have been possible to hack together a habitat for humans. But its hydrogen-based atmosphere has slowly evaporated into space, and trying to bend the rules of nature to lodge a shelter in that wasteland for such fragile creatures as humans is just not feasible.