Space Colonies

[ryan]

Should we build colonies in space first and then build them on other planets; why or why not?

How important do you think it is for space colonies to become a reality?

What reasons are there for why we should be making space colonies a reality as soon as possible?

What reasons are there for why we shouldn't be making space colonies a reality as soon as possible?

 

[Loren Pechtel]

In space. I see little reason to colonize other planets beyond mining and scientific bases.

 

[James Brown]

What would be the reason for non-planet-based space colonies?

 

[ryan]

What would be the reason for non-planet-based space colonies?

No earthquakes, hurricanes, tornadoes, flooding (natural), unwanted weather, lightning, and any other unwanted surprises. A colony completely built from scratch would seem to give us the most control over it.

The colony could be mobile in case there are dangerous asteroids, nearby unstable stars etc. Plus, it could go where the needed resources are.

They could also customize it so that the structure itself could serve multiple purposes. It would seem easier to build it on Earth instead of trying to build the same stuff with the resources that may of may not be optimal for doing so on another planet.

 

[Bronzeage]

What would be the reason for non-planet-based space colonies?

No earthquakes, hurricanes, tornadoes, flooding (natural), unwanted weather, lightning, and any other unwanted surprises. A colony completely built from scratch would seem to give us the most control over it.

The colony could be mobile in case there are dangerous asteroids, nearby unstable stars etc. Plus, it could go where the needed resources are.

They could also customize it so that the structure itself could serve multiple purposes. It would seem easier to build it on Earth instead of trying to build the same stuff with the resources that may of may not be optimal for doing so on another planet.

There needs to be a better reason to build a colony than tradition. In the history of the world, the reason for colonization has always been economics. Even though lip service is paid to the desire for political freedom, the basis of all colonies(the successful ones, for certain) it their economic return for the mother country. This return must exceed all the costs of administration and maintenance of the colony.

Space exploration for the purpose of broadening man's knowledge of the universe is a great reason for going to the Moon or Mars, but one will notice, once the Moon was explored we haven't gone back. The reason is simple. There's nothing to do there that can't be done cheaper on Earth. Once you've seen one crater, you've seen them all.

This is without consideration of the technical problems of living in a weightless environment. Weightlessness may come to be seen as analogous to radiation exposure. A person can be exposed to a little radiation with no ill effects. Sustained exposure causes permanent damage. We are now seeing the effects of long term low gravity on the human body. People who commit themselves to live in space may commit themselves to die in space, because as little as six months in zero gravity may make it very difficult for them to return to Earth and live a normal life. This is a very serious matter for long distance space flight. The projected time for a trip to Mars is about 7 months.

This maybe just a matter of technology. We may develop spacecraft which can create the stress of gravity on the human body. It is telling to remember, this is a problem even Gene Roddenberry never even tried to solve. Starfleet personnel walk the halls of the Enterprise with their feet on the floor. The special effects required to make actors float around the set were cost prohibitive. Roddenberry, the technophile, never found a theoretical basis for normal Earth gravity on the Enterprise, so the issue was simply ignored.

Once the physical problems of living without gravity are solved, we will need to find someway to pay for the whole thing. We need to remember a few stark facts that all life on Earth is dependent upon life on Earth. Even the fuel I put in my car was once a living organism. This is the source of wealth on our planet. In space, we either find organic substances, or bring them with us. The non-organic substances on this planet are used mostly for building materials in places where there aren't enough trees to harvest for timber. There has never been a shortage of rock on planet Earth, and that is just about all we find once we leave Earth's gravity.

 

[ryan]

No earthquakes, hurricanes, tornadoes, flooding (natural), unwanted weather, lightning, and any other unwanted surprises. A colony completely built from scratch would seem to give us the most control over it.

The colony could be mobile in case there are dangerous asteroids, nearby unstable stars etc. Plus, it could go where the needed resources are.

They could also customize it so that the structure itself could serve multiple purposes. It would seem easier to build it on Earth instead of trying to build the same stuff with the resources that may of may not be optimal for doing so on another planet.

There needs to be a better reason to build a colony than tradition. In the history of the world, the reason for colonization has always been economics. Even though lip service is paid to the desire for political freedom, the basis of all colonies(the successful ones, for certain) it their economic return for the mother country. This return must exceed all the costs of administration and maintenance of the colony.

Space exploration for the purpose of broadening man's knowledge of the universe is a great reason for going to the Moon or Mars, but one will notice, once the Moon was explored we haven't gone back. The reason is simple. There's nothing to do there that can't be done cheaper on Earth. Once you've seen one crater, you've seen them all.

There are at least three motivations for space colonies that I am certain are greater than finding routes to buy spices.

One is biotechnology. Biotechnology is ever increasing lifespans. We may have to leave this planet in 100 years from overpopulation. It might come down to people who want to live past, say, 150 must do so in space. It's a long time away, but we might be ready for it if we start now.

Two is resource depletion. We may have to bring in metals from asteroids and other planets. James Cameron claims that there are asteroids within the asteroid belt that are worth trillions of dollars each. Again, a major resource depletion is a long time away, but we can be ready by starting now.

Three is escaping the destruction of Earth. The health of the entire human race is on borrowed time. Our continuing industrial presence will present problems and catastrophes that will be impossible to predict. In other words, disease, weather patterns, pollution, war etc. all must continue to change unexpectedly as we continue with this massively uncontrolled experiment on Earth. Irreversible devestation can happen any day now, and it can happen quick, so we must start pushing for colonial planning and development. It can start as tourism, exploration, asteroid mining etc.

This is without consideration of the technical problems of living in a weightless environment. Weightlessness may come to be seen as analogous to radiation exposure. A person can be exposed to a little radiation with no ill effects. Sustained exposure causes permanent damage. We are now seeing the effects of long term low gravity on the human body. People who commit themselves to live in space may commit themselves to die in space, because as little as six months in zero gravity may make it very difficult for them to return to Earth and live a normal life. This is a very serious matter for long distance space flight. The projected time for a trip to Mars is about 7 months.

This maybe just a matter of technology. We may develop spacecraft which can create the stress of gravity on the human body. It is telling to remember, this is a problem even Gene Roddenberry never even tried to solve. Starfleet personnel walk the halls of the Enterprise with their feet on the floor. The special effects required to make actors float around the set were cost prohibitive. Roddenberry, the technophile, never found a theoretical basis for normal Earth gravity on the Enterprise, so the issue was simply ignored.

Artificial gravity is easily made. There just needs to be rotation a(rad) = v^2/r = 9.81.

Once the physical problems of living without gravity are solved, we will need to find someway to pay for the whole thing. We need to remember a few stark facts that all life on Earth is dependent upon life on Earth. Even the fuel I put in my car was once a living organism. This is the source of wealth on our planet. In space, we either find organic substances, or bring them with us. The non-organic substances on this planet are used mostly for building materials in places where there aren't enough trees to harvest for timber. There has never been a shortage of rock on planet Earth, and that is just about all we find once we leave Earth's gravity.

The source of energy for all life (except chemosynthetic organisms at the bottom of oceans) get their energy from the Sun. We get more power from the Sun in space per unit area than we do on Earth.

 

[Perspicuo]

Once space bases become fun and economical, who wouldn't?

We know one day astronomical disaster is bound to reach Earth, even if we succeed in stopping our ravaging of the home planet. There's wisdom in not putting all your eggs in the same basket.

 

[Keith&Co.]

There are at least three motivations for space colonies that I am certain are greater than finding routes to buy spices.

One is biotechnology. Biotechnology is ever increasing lifespans.

And because ryan is terrified of dying, ryan wants a space station to make him immortal.
You just need to show that orbiting space colonies make this immortality cheaper to acquire than research ing at the bottom of a gravity well.

We may have to leave this planet in 100 years from overpopulation. It might come down to people who want to live past, say, 150 must do so in space.

It might come down to? Are there any details making this at all likely, that ONLY space colony people can live an extra 100 years?

Two is resource depletion. We may have to bring in metals from asteroids and other planets.

Wouldn't it be cheaper to invest in long-term space ships than a colony? I mean, why would a colony be better? We'd have to invest a lot of resources into making a space colony, which would either hasten Earth's resource depletion, or divert resources we need on Earth to the colony.
Not a positive gain, either way.

James Cameron claims

In my early schooling, if we defended a statement with 'i saw it on TV' we got beaten. You're quoting a guy that makes movies as, what, an expert?

Three is escaping the destruction of Earth.

Or we could channel the resources into preventing the destruction of Earth.
Probably get more payback from that, wouldn't you say? We'd still have the environment we evolved to be in, rather than have to build one from scratch.

Irreversible devestation can happen any day now, and it can happen quick, so we must start pushing for colonial planning and development.

The sky may be falling, so let's climb up above the sky?
This is a good reason to divert resources from problems down here on Earth? For fantasy problems that might come to be on Earth?

Artificial gravity is easily made. There just needs to be rotation a(rad) = v^2/r = 9.81.

That just makes your colony more expensive. It requires more resources, which would divert more away from you resource depletion plan...

 

[Bronzeage]

...
The source of energy for all life (except chemosynthetic organisms at the bottom of oceans) get their energy from the Sun. We get more power from the Sun in space per unit area than we do on Earth.

The Sun shines on the Moon and Mars, and they are both big rocks. There must be something more to this life thing than sunshine.

Overpopulation and depletion of resources are science fiction plot devices, not economic realities. In order to establish space colonies, either in open space or on planet surfaces, we will have to use surplus wealth to invest in the infrastructure which makes this possible. Everything shot into space is something which can't be used on Earth. For every person who accompanies the payload, there will be millions born the day of liftoff.

Space exploration is like living on an island and tearing down your front porch to build a ship. This makes sense if you don't need the porch, or can afford to build another one. If you are really desperate to get off the island, you might tear down the entire house. One of the advantages of life on Earth is that despite short term local shortages, there is more stuff on Earth than we need to survive. If we move into space, it will be very difficult to duplicate those conditions. The aforementioned Gene Roddenberry solved that problem by imagining a machine that makes stuff out of available atoms as if they were legos.

The idea of life in space is fun to think about, but we have plenty of economic models to demonstrate the reality of it. How many years in a row would a man plant a garden, if every harvest produce less food than the seeds he planted? There has to be a foreseeable return in order to keep up the effort.

 

[dystopian]

What would be the reason for non-planet-based space colonies?

Efficiency. It takes considerable energy to escape a planet's gravity well; a problem that doesn't exist with space habitats.

 

[ryan]

And because ryan is terrified of dying, ryan wants a space station to make him immortal.
You just need to show that orbiting space colonies make this immortality cheaper to acquire than research ing at the bottom of a gravity well.

The point I was trying to make is that biotechnology may cause overpopulation. A solution is to have the option to populate elsewhere.

We may have to leave this planet in 100 years from overpopulation. It might come down to people who want to live past, say, 150 must do so in space.

It might come down to? Are there any details making this at all likely, that ONLY space colony people can live an extra 100 years?

Well if multiple generations are overlapping and the Earth is overpopulated, then ...

Two is resource depletion. We may have to bring in metals from asteroids and other planets.

Wouldn't it be cheaper to invest in long-term space ships than a colony? I mean, why would a colony be better? We'd have to invest a lot of resources into making a space colony, which would either hasten Earth's resource depletion, or divert resources we need on Earth to the colony.
Not a positive gain, either way.

Do you really think that we will automate the entire process when we don't even do so on Earth? If we could, then why don't we automate everything on Earth too? We should all be on permanent vacations then.

James Cameron claims

In my early schooling, if we defended a statement with 'i saw it on TV' we got beaten. You're quoting a guy that makes movies as, what, an expert?

Well, because James Cameron is only a voice for professionals such as NASA employees at the Planetary Resources firm, http://www.planetaryresources.com/team/ then I guess I have to reluctantly agree.

Three is escaping the destruction of Earth.

Or we could channel the resources into preventing the destruction of Earth.

We could, but will we. [And no I did not forget the question mark in the last sentence.]

We'd still have the environment we evolved to be in, rather than have to build one from scratch.

Look at the air pollution in China; I think that we can both agree that we are not in the same environment that we evolved in.

Irreversible devestation can happen any day now, and it can happen quick, so we must start pushing for colonial planning and development.

The sky may be falling, so let's climb up above the sky?

Your solution seems to hold up the sky.

We can do only so much to a steam engine, but it may never do what we need it to do. At some point there needs to be a new design.

This is a good reason to divert resources from problems down here on Earth?

I have no idea how you can use that as an argument. Please see,http://www.planetaryresources.com/2014/06/fuelspace/ .

For fantasy problems that might come to be on Earth?

I don't understand your question.

Artificial gravity is easily made. There just needs to be rotation a(rad) = v^2/r = 9.81.

That just makes your colony more expensive. It requires more resources, which would divert more away from you resource depletion plan...

There must be ways in getting around a constant input of energy if one uses the conservation of momentum creatively enough.

 

[dystopian]

Or we could channel the resources into preventing the destruction of Earth.
Probably get more payback from that, wouldn't you say? We'd still have the environment we evolved to be in, rather than have to build one from scratch.

Untenable long term. A stray gamma burst could wipe us all out and there'd be nothing we could do to stop it. I don't necessarily share Ryan's alarmism (nor some of his more esoteric arguments); but long term we really don't have any choice but to spread our species into space if we want to survive. That's not alarmism that 's just statistical inevitability. Putting all our eggs into one vulnerable little basket is not the smartest thing to do. Incidentally, it's not as if humans are currently inhabiting the environment we evolved to be in; we've spread across the globe into environments that are not optimal to our survival. Space is just a little more extreme in that regard.

The sky may be falling, so let's climb up above the sky?
This is a good reason to divert resources from problems down here on Earth? For fantasy problems that might come to be on Earth?

This is a non-argument that's often brought up in this sort of discussion. It presupposes that space flight is diverting resources that'd be better spent solving problems here on earth; when in fact space development would *add* resources that can then be used to solve the problems on earth. It also presupposes that if we didn't develop space that we'd then actually focus on our terrestrial problems, which seems highly unlikely the way we're acting right now. Finally, it also presupposes that we can't somehow try to fix our problems here while at the same time also developing space; which just isn't true.

That just makes your colony more expensive. It requires more resources, which would divert more away from you resource depletion plan...

Actually, it doesn't really do that; not when you already have an existing space-based infrastructure. Such a design WOULD be more complex than the ISS and would require a lot more lift capacity to construct if you start everything out on earth, but assuming you have orbital construction capabilities and gather the resources from the lunar surface or near earth asteroids, rotating a station to provide gravity wouldn't be all that expensive, and would certainly make things like medical maintenance of the occupants much cheaper. The start-up cost of developing space is high, yes, but after you've done that things get considerably cheaper.

 

[Keith&Co.]

The point I was trying to make is that biotechnology may cause overpopulation. A solution is to have the option to populate elsewhere.

Or it may solve all our problems. And we won't need a solution. If you're going to throw science fiction into the mix, we can support any output we want, along wiht any output we don't want. They're all equally resonable once you start saying 'may one day be that' something happens....

We may have to leave this planet in 100 years from overpopulation. It might come down to people who want to live past, say, 150 must do so in space.

It might come down to? Are there any details making this at all likely, that ONLY space colony people can live an extra 100 years?

Well if multiple generations are overlapping and the Earth is overpopulated, then ...

So.... That's a no.

Do you really think that we will automate the entire process when we don't even do so on Earth?

I didn't say automate. i said build spaceships, not space colonies. Go out, find an asteroid, bring it into orbit, scavenge. Build a space elevator and make it a day job.

James Cameron claims

In my early schooling, if we defended a statement with 'i saw it on TV' we got beaten. You're quoting a guy that makes movies as, what, an expert?

Well, because James Cameron is only a voice for professionals such as NASA employees at the Planetary Resources firm, http://www.planetaryresources.com/team/ then I guess I have to reluctantly agree.

Wow. A private business has a celebrity endorsement. They can't possibly be anything but fully correct and complete in any press release they make, trying to draw investments, so that they can profit from exploring space... Which, come to think of it, is exactly what bronzeage said, wasn't it? You need to make it economically feasible to profit from the venture.
MAAAAAAAAAAAAAYBE you could quote someone who doesn't have a vested interest in your opponent's side of the argument?

Your solution seems to hold up the sky.

And that makes my fantasy less useful than your fantasy...why? Look, you've got a basic summer movie plot going, or maybe a mid-season replacement series premise. Clearly, you're selecting from the possible 'what ifs' to come to the plot device you find most attractive.
And you're just flat dismissing objections that don't support the screenplay you want to write.

As usual.

There must be ways in getting around a constant input of energy if one uses the conservation of momentum creatively enough.

Which would still require making a more complicated space colony, which would require resources, which would mean that the colony is not replacing depleted resources. You self-refute your own plot device.
Like MST3K, but not as funny.

 

[Keith&Co.]

Untenable long term. A stray gamma burst could wipe us all out and there'd be nothing we could do to stop it.

Well, in context, ryan's throwing out so much 'maybe' and 'could be' and imaginary advances in science and technology, to push his argument, it's just as easy to say we'll invent a gamma burst shield and cover the Earth.
Of course, for the movie, there has to be conflict, so for most of the two hours, the shield can only cover one continent at a time and they fight over who gets the umbrella until in the last 14 minutes the hero figures an orbit to put the umbrella into that covers the whole planet ,yay ,happy ending.

 

[Keith&Co.]

This is a non-argument that's often brought up in this sort of discussion. It presupposes that space flight is diverting resources that'd be better spent solving problems here on earth; when in fact space development would *add* resources that can then be used to solve the problems on earth. It also presupposes that if we didn't develop space that we'd then actually focus on our terrestrial problems, which seems highly unlikely the way we're acting right now.

Oh, yeah. Stipulated. I'm fully in favor of space exploration, space colonization, developing space resources and all that.
But i'm more in favor of a rational approach, and ryan's hand-waiving of difficulties deserves to be dope-slapped. And it doesn't matter if it's a good argument or a bad one, he'll just insist it's not a problem and go on.
And he's saying that going out to space MUST be the way to solve problems down here. Mostly, i think he just wants ryan to get away from problems down here.

 

[Loren Pechtel]

What would be the reason for non-planet-based space colonies?

Planets are dangerous places.

Out in space the only threats are radiation (which is easily stopped by surrounding your colony with 6' of mining slag) and impacts. Your radiation shield will stop the small stuff, you can detect the big stuff far enough out to take action. Furthermore, planets suck in impactors--they hit far harder and somewhat more frequently on a planet than in space. Even if something too big to stop in time comes along you're still better off in space--a direct hit takes you out whether you are in space or on a planet but a near miss does nothing but make for brown underwear in space but still takes you out on a planet.

 

[Loren Pechtel]

There needs to be a better reason to build a colony than tradition.

That has nothing to do with space vs planets.

Space exploration for the purpose of broadening man's knowledge of the universe is a great reason for going to the Moon or Mars, but one will notice, once the Moon was explored we haven't gone back. The reason is simple. There's nothing to do there that can't be done cheaper on Earth. Once you've seen one crater, you've seen them all.

We have gone back, just with robots rather than humans.

There are three things I can think of off the top of my head that are much better done on the moon:

1) Obtaining raw materials for space-based construction. A linear motor can easily throw them off the moon--while nobody has built one powerful enough that's just a matter of not having a need. The engineering is understood, just make one longer. While we could build the tosser here on Earth the flight through the atmosphere is quite another matter.

2) Radio astronomers would love the lunar farside, at least until we start doing a lot of development there.

3) Once you're to the point of major engineering projects on the moon: Build a linear motor wrapped around the lunar equator. It's doubled up so anything on it can ride on (actually levitated above) tracks above as well as tracks below. A spacecraft goes around the track as many times as desired and then is ejected. If you'll accept 5gs on the track the ejection velocity is high enough to put you on a transfer orbit for any point in the solar system, including interstellar space. If you don't mind some hellish aerobraking it means no worrying about launch windows for the nearby planets with atmospheres.

This is without consideration of the technical problems of living in a weightless environment. Weightlessness may come to be seen as analogous to radiation exposure. A person can be exposed to a little radiation with no ill effects. Sustained exposure causes permanent damage. We are now seeing the effects of long term low gravity on the human body. People who commit themselves to live in space may commit themselves to die in space, because as little as six months in zero gravity may make it very difficult for them to return to Earth and live a normal life. This is a very serious matter for long distance space flight. The projected time for a trip to Mars is about 7 months.

1) I've never seen a colony design that was weightless. We are talking structures large enough that spin gravity is fine for humans. (Note, however, that the large open spaces sometimes depicted do not work. You can't permit too great an open vertical space without causing major air movement problems.)

2) Spin gravity can even be used by spaceships, albeit precluding the use of shadow shielding for solar flare protection. They don't need to be huge, just split them into two pieces connected by a cable. You can use electromagnetic shielding, though. (Mount an electron beam accelerator on the spacecraft, IIRC a few hundred megavolts is enough for most shielding, you need gigavolts to stop all the cosmic rays. The objective is building up a positive charge on the spacecraft. Positively charged particles will be slowed by this, negatively charged ones accelerated. The total infalling energy is the same but you replace the protons and alphas with electrons--and electrons are *MUCH* easier to stop.)

Once the physical problems of living without gravity are solved, we will need to find someway to pay for the whole thing. We need to remember a few stark facts that all life on Earth is dependent upon life on Earth. Even the fuel I put in my car was once a living organism. This is the source of wealth on our planet. In space, we either find organic substances, or bring them with us. The non-organic substances on this planet are used mostly for building materials in places where there aren't enough trees to harvest for timber. There has never been a shortage of rock on planet Earth, and that is just about all we find once we leave Earth's gravity.

At first we will have to bring the carbon and nitrogen, perhaps the hydrogen. (That's why they are so interested in finding water on the moon--hydrogen.) Some heavy metals will also be needed. You only need enough to bootstrap to the asteroid belt, though--everything we want can be found there, mostly all broken out for us already. The only problem is the distances--but note that while such trips will be slow they aren't expensive.

 

[Loren Pechtel]

There needs to be a better reason to build a colony than tradition. In the history of the world, the reason for colonization has always been economics. Even though lip service is paid to the desire for political freedom, the basis of all colonies(the successful ones, for certain) it their economic return for the mother country. This return must exceed all the costs of administration and maintenance of the colony.

Space exploration for the purpose of broadening man's knowledge of the universe is a great reason for going to the Moon or Mars, but one will notice, once the Moon was explored we haven't gone back. The reason is simple. There's nothing to do there that can't be done cheaper on Earth. Once you've seen one crater, you've seen them all.

There are at least three motivations for space colonies that I am certain are greater than finding routes to buy spices.

One is biotechnology. Biotechnology is ever increasing lifespans. We may have to leave this planet in 100 years from overpopulation. It might come down to people who want to live past, say, 150 must do so in space. It's a long time away, but we might be ready for it if we start now.

Agreed--in time I expect we will see longevity only permitted with emigration. And I don't think it's that far down the road, either.

Two is resource depletion. We may have to bring in metals from asteroids and other planets. James Cameron claims that there are asteroids within the asteroid belt that are worth trillions of dollars each. Again, a major resource depletion is a long time away, but we can be ready by starting now.

Check the depletion times for some of the important stuff. It's not a long time away.

A simple one: Consider all the hype about fuel cell cars. With current technology we could replace all the US cars with fuel cell cars. Once.

Three is escaping the destruction of Earth. The health of the entire human race is on borrowed time. Our continuing industrial presence will present problems and catastrophes that will be impossible to predict. In other words, disease, weather patterns, pollution, war etc. all must continue to change unexpectedly as we continue with this massively uncontrolled experiment on Earth. Irreversible devestation can happen any day now, and it can happen quick, so we must start pushing for colonial planning and development. It can start as tourism, exploration, asteroid mining etc.

Yup. In the old days a killer disease would burn itself out pretty quickly. Everyone dies or is immune, end of disease. As people moved around more the ability of killer diseases to survive went way up--it took a worldwide effort to nail smallpox. Now look at what happened with SARS--it wasn't contagious enough to be catastrophic but even then once it found it's way to a modern city it scattered around the world in days. Picture a more contagious version of SARS--society probably would have collapsed and we wouldn't be here.

 

[ryan]

Or it may solve all our problems. And we won't need a solution. If you're going to throw science fiction into the mix, we can support any output we want, along wiht any output we don't want. They're all equally resonable once you start saying 'may one day be that' something happens....

Increasing lifespans with biotechnology is science fiction now?! I think we have been doing this before science fiction was even coined.

Well if multiple generations are overlapping and the Earth is overpopulated, then ...

So.... That's a no.

You have lost me, again.

Do you really think that we will automate the entire process when we don't even do so on Earth?

I didn't say automate. i said build spaceships, not space colonies. Go out, find an asteroid, bring it into orbit, scavenge. Build a space elevator and make it a day job.

Sure that might be how it starts, but I can't imagine people not staying out there, especially away from this ticking time bomb [alarm].

Well, because James Cameron is only a voice for professionals such as NASA employees at the Planetary Resources firm, http://www.planetaryresources.com/team/ then I guess I have to reluctantly agree.

Wow. A private business has a celebrity endorsement. They can't possibly be anything but fully correct and complete in any press release they make, trying to draw investments, so that they can profit from exploring space... Which, come to think of it, is exactly what bronzeage said, wasn't it? You need to make it economically feasible to profit from the venture.
MAAAAAAAAAAAAAYBE you could quote someone who doesn't have a vested interest in your opponent's side of the argument?

What the hell are you talking about? I am adding reasons to economic motivation. I think that keeping people alive is more important than economy because you need people to even have an economy.

I didn't mean to dismiss what Bronzeage said; I was adding motivations that I thought were even more important than economy.

Your solution seems to hold up the sky.

And that makes my fantasy less useful than your fantasy...why? Look, you've got a basic summer movie plot going, or maybe a mid-season replacement series premise. Clearly, you're selecting from the possible 'what ifs' to come to the plot device you find most attractive.
And you're just flat dismissing objections that don't support the screenplay you want to write.

The Earth seems to involve more variables. I am a strong believer in bottom-up design, and I do not understand how someone wouldn't be.

There must be ways in getting around a constant input of energy if one uses the conservation of momentum creatively enough.

Which would still require making a more complicated space colony, which would require resources, which would mean that the colony is not replacing depleted resources. You self-refute your own plot device.
Like MST3K, but not as funny.

???

 

[ryan]

Yup. In the old days a killer disease would burn itself out pretty quickly. Everyone dies or is immune, end of disease. As people moved around more the ability of killer diseases to survive went way up--it took a worldwide effort to nail smallpox. Now look at what happened with SARS--it wasn't contagious enough to be catastrophic but even then once it found it's way to a modern city it scattered around the world in days. Picture a more contagious version of SARS--society probably would have collapsed and we wouldn't be here.

Sadly, it is probably going to take a cataclysmic disaster unlike anything ever known for us to really take action on leaving the planet; if we come out of it, then the motivation will certainly be there.