Fiero88Formula wrote...
I know most of you have already beat and beat on this topic like crazy.
However, most of you are pointing out social, religious, and economical reasons by which space colonization would be acceptable. There's however an actual physical problem that space colonization presents to the human race, and it has been studied extensively by scientists.
Some scientists believe that extensive settlement on a terrestrial sphere other than earth could potentially reshape human genetics. You're likely not going to find this on wiki or similar sources. One study that has been done - and what is often cited to press away the nay-sayers that speak of the moon landing never happening - is that Neil Armstrong and Buzz Aldrin have what is known as a symptom called "dark matter brain". It's basically because they were positioned on the moon for some time that they developed some sort of restructuring of their brains. I don't exactly know why it's the brain explicitly, but it has something to do with the fact that your brain is the primary receiver of all the signals from your body. Armstrong and Aldrin were extensively tested when they returned from their trip, and some years later were found to have some indentions in their brain matter. If I remember correctly, scientists hypothesize that the reason it occurs is because of different gravitational pulls upon the body. While in space there is essentially no or little gravity, when your on a planet you are subjected to a different gravitational force than what you are accustomed to and what shaped your body.
Basically what this means is that humans could not stay on any spherical body in the solar system for an extended period of time - they would have to be constantly rotated and travel back and forth between Earth and where ever. This would mean that space travel would be at an incredible cost.
Apparently, the only belief around this 'dark matter brain' theory is hypothesized to be water - thus another reason why it doesn't affect us as much here on Earth. Scientists believe that whatever type of structure would be built on another spherical body would require it to be surrounded by water to help block the 'dark matter brain' syndrome.
Do note I cannot verify how true any of that is that I just said. I had a co-worker about four years ago show me an article in a science journal that had been done on it, and I did my own little research for a bit and that's pretty much the gist of it. I know there's the deal with the Russian space station where cosmonauts were stationed there for some time but they were rotated out at regular intervals.
I'm sorry but what you've written is utter bullshit.
There is no such thing as "black matter brain". (Back than black matter wasn't in the know how yet as it is a mathematically predicted - and not yet proven - phenomenon that tries to solve the problem of integrating general relativity into quantum physics).
You could have written about a myriad things that actually could change the colonists, like the effect gravity has on phenotypical expression of the genome (people would be taller or smaller, we don't know yet which will happen since no creatures were yet raised in lower gravity) or its physiological effects (some of our endocrine systems could be screwed up) or its psychological effects (people raised in lower gravity could suffer from lower IQ). Remember that I talk about people born and raised in lower gravity. Our astronauts didn't suffer from any of this.
All of this is possible, but our understanding currently doesn't make any of them likely. People even on Earth are brought up in very different environments and we can already do a lot to fix things that are the result of the environment.
However while lower gravity has a potential to influence all of the above we're yet to see evidence that would indicate drastic problems.
Add in more hidden and sinister stuff like how the microbes we must inevitably carry with us will react to the new environments. Like how our biochemistry depends on this microbes and their chemistry in turn depends on the specific composition of their environment. All of which we must religiously replicate wherever we go as well as shield them from unexpected dangers (like higher solar radiation).
In the end I believe it will take mature genetic engineering to tailor humans to whatever place we go to, as it will be the only self-sustaining solution as well as the one solution that won't require tons of money in the long run.
Extended stay in microgravity - that's freefall! In space you still *do* have gravity, it just doesn't affect you - can results in muscle loss and weakened bones and heart conditions. I'm talking about half to one year. A couple of weeks or months won't produce severe problems. Extended stay in microgravity will require artificial gravity (like a spinning station that uses centrifugal force to simulate gravity) to amend these health problems.
What it comes down to are "mere" economic factors and the embarrassing detail that we can't yet make - or even operate! - a self sustaining life support system. To have any prolonged stay in anywhere the Solar System other than Earth we would have to ship supplies to it for quite a while until we got the hang of it...
...and those supplies would cost a lot as they'd need to be raised into orbit and from there transported to wherever. Even the lift into orbit demands exorbitant prices by our current economy.
With advances in our space lift capability we will be able to operate small stations near Earth (the ISS is pretty much the prototype of this, but right now it demands the resources of not one, but three superpowers). It won't be cheap, and it will be a really gradual, slow development (Say 3-5% per year).
Don't expect any sizable population until we're into the late 2200'.