[Thunderbird]

Originally Posted by Moontanman

No matter how green we are humans will eventually destroy the earth's ecosystems and humans will become extinct. The Earth is finite, the human race is not. the only way the human race and the Earth's ecosystem can survive is for humans to move into space. Any culture that is not advancing is declining, there is no way to maintain a static society. Colonies are a way to obtain natural resources with out destroying the Earth's ecosystems, materials that cannot be made o the earth can be made in space (metal foam is one of the potentially most useful things we could make in space, huge crystals, zero gee bearings, the list is quite long.) To make these things will require people living in space. It would be far too expensive to maintain small factories from the Earth. Finally how can you put a price on the insurance value of not having all your eggs in one basket should a planetary disaster occur? Humans got to where they are by advancing, expanding to the next level, the next level is space. No matter what we do the Earth will become uninhabitable sooner or later. I love the Earth, I want to do all I can to make it a better place but no matter how hard I or everyone else tries it will eventually die. We can either Terra form other planets which will eventually die just like the earth or we can start making small versions of the Earth in the form of space colonies. If we do we will never run out of resources or space and we will have the opportunity to occupy the entire galaxy and leave all the planets to evolve in their own way. Not only will we survive but the genome of the Earth will survive as well. We will take as many animals and plants with us as we can. the more complex we make our artificial ecosystems the better they will be for us. Does any of this make sense to you?

No.
If any of this was a viable natural evolutionary stage, from a terrestrial existence to life migrating across the galaxy, it would be obvious by now. For one thing this perfect little sphere of ours would have been snapped up long ago as prime beach front property. Since it wasn't, and since we appear to be alone in our solar system. [I do not see a space high way near by] It appeared all the neighbors know a bit more than we do on the best way to survive and evolve. Namely its not about moving because you've dirtied your house, but to get your house in order.

[Moontanman]

Originally Posted by Thunderbird

No.
If any of this was a viable natural evolutionary stage, from a terrestrial existence to life migrating across the galaxy, it would be obvious by now. For one thing this perfect little sphere of ours would have been snapped up long ago as prime beach front property. Since it wasn't, and since we appear to be alone in our solar system. [I do not see a space high way near by] It appeared all the neighbors know a bit more than we do on the best way to survive and evolve. Namely its not about moving because you've dirtied your house, but to get your house in order.

T-Bird why do you ignore my points and try to make it seem like i am making others? Do you really think that because the Earth hasn't been occupied by aliens it means they are all staying on their home worlds going down with the ship?

Colonizing another planet is problematical at best, even if the local ecosystem didn't poison you outright it's unlikely you could live on any plants or animals that lived there. Disease and allergens would probably keep you from exactly living the good life if the local life forms were compatible. Then you have the moral problem of interfering with another ecosystem. Leaving these things aside I'll say it again, the ecosystem of the Earth is DOOMED! The Earth will only become less and less inhabitable as time goes on, even if we aren't here this will be true. Our presence only hurries the process along. then you have the possibility of a planetary disaster, a major asteroid strike will happen, planetary scale volcanic eruptions (super volcanoes, major lava eruptions IE the Siberian traps) or even man made catastrophes like global warming will eventually wipe out or make the continued existence of the human race unlikely to say the least. If nothing else space colonies would be like an insurance policy against those things. Just because no one has showed up to take the Earth away from us doesn't mean space colonization isn't the next step (not inevitable, we could just die out) we need to take. Space colonies are just the next intelligent step. It is very possible we are the only civilization in the milky way galaxy or at least the only one for thousands of light years. We cannot help but dirty our nest, we cannot clean it up enough to keep it from being dirty. The are simply way too many people and mandatory birth control is OK for all those other people but not for us, unfortunately there are no other people, everyone is part of the problem. Setting our house right is at best a temporary solution, we still need to pursue that course but ultimately we will just be fighting a loosing battle. Do you really want to live on a world where all the animal life has been killed off by habitat destruction and all you have is hordes of people living in squalor? Or do you want to kill off 90% of humanity so the ecosystem can limp along a little longer? Give me a really viable alternative that will allow humans to live a life worth living on the Earth forever. There isn't one, even the sun will not cooperate, it will extinguish life on the Earth eventually if we can avoid all the short term disasters.

[Pyrotex]

Hmmm... perhaps we should narrow our focus to that class of global disasters that we are likely to face in the next 100 to 200 years. I vote we exclude the Sun going nova.

[Moontanman]

Originally Posted by Pyrotex

Hmmm... perhaps we should narrow our focus to that class of global disasters that we are likely to face in the next 100 to 200 years. I vote we exclude the Sun going nova.

Well Nova wasn't what I had in mind but plenty of other problems will have the opportunity to get us way before the sun expands to the point we can't survive. The real point is to exploit the resources available in space and to expand the human race beyond the earth. It will be hundreds if not thousands of years before we move to the next star but it's never too soon to start things moving in that direction. I wouldn't be surprised if in the process of developing the technologies necessary to make the move into space we discover things to help us out on the Earth. Aneutronic fusion is one really big possibility that cannot be ignored. Aneutronic fuel is common in the regolith of airless space bodies but rare on the Earth. We don't know what we will accomplish with we are trying to accomplish space development. Insurance is always a good thing when you need it.

[modest]

Originally Posted by CraigD

Rather than attempting to armor a giant spacecraft, you could follow Bill’s advice about “just moving on with life [aboard a spacecraft]”, and make its skin as thin as structurally practical while providing adequate radiation shielding, accepting that an occasional meteor will cleanly penetrate it.

I doubt either will be necessary (although both could be intelligently used). We can currently shoot down incoming missiles traveling at mach-whatever with a single radar dish and a gatling gun. In a few hundred years it’s hard to imagine we couldn’t track a problem (small as sand) and destroy it with clockwork precision. Radars work very well in space at any frequency. Lasers too I guess... Or, some offensive projectile on projectile action - uh, that is to say, it would be easier to shoot a bit of incoming meteor with a bullet in the absence of air resistance.

Anyway, just caught up on this thread and thought I'd offer that

-modest

[Moontanman]

Originally Posted by modest

I doubt either will be necessary (although both could be intelligently used). We can currently shoot down incoming missiles traveling at mach-whatever with a single radar dish and a gatling gun. In a few hundred years it’s hard to imagine we couldn’t track a problem (small as sand) and destroy it with clockwork precision. Radars work very well in space at any frequency. Lasers too I guess... Or, some offensive projectile on projectile action - uh, that is to say, it would be easier to shoot a bit of incoming meteor with a bullet in the absence of air resistance.

Anyway, just caught up on this thread and thought I'd offer that

-modest

Great idea, I have been reading about lasers that are in the prototype phase that are small enough to put in a Humvee and can shoot down incoming artillery shells. Even fighter planes will have solid state lasers to fight each other and incoming missiles. it's not to difficult to imagine lasers being used to vaporise small meteors and even moves larger ones off course. It would be good to see military tech used for peaceful purposes.

[CraigD]

Originally Posted by modest

We can currently shoot down incoming missiles traveling at mach-whatever with a single radar dish and a gatling gun. In a few hundred years it’s hard to imagine we couldn’t track a problem (small as sand) and destroy it with clockwork precision. Radars work very well in space at any frequency. Lasers too I guess... Or, some offensive projectile on projectile action - uh, that is to say, it would be easier to shoot a bit of incoming meteor with a bullet in the absence of air resistance.

I agree – though modest’s assessment of current close-in weapon systems capabilities is, I think, a bit overoptimistic, given that none have yet been successful in actual combat, and frequently have failed in controlled tests. These systems are, nonetheless, impressive: ones like the US’s Phalanx radar-aimed gun not only track their target via RADAR, but track their own projectiles, correcting their aim to assure a hit!

I think CIWS make sense for future spacecraft, especially the giant habitats under discussion in this thread, though less as a defense against natural hazard, than in the usual role as a defense against man-made attack. Although it’s comforting to assume that warfare, symmetrical and asymmetrical, will soon cease to exists, it’s not a scientifically supported assumption. Despite dramatic increases in civil, medical, and information technology in most recent human history, and admirable efforts to avert it through legal, governmental, spiritual and/or psychological means, acts of warfare continue to occur. Many of the best – which to a large extent means most economical and promptly constructable - space habitat designs are very resilient against natural impactors, but vulnerable to total catastrophic destruction by much less costly and technically sophisticated weapons. While a habitat wall can be engineered so that an ordinary meteoroid can penetrate with minimal and easily repairable damage, a fairly low-tech explosive warhead-tipped missile appears nearly impossible to handle in this manner. An active defense system – a CIWS by any other name - is called for.

Having established the need for defensive weapons, the engineering of them is an interesting, and in my experience, under-explored subject. My guess is that, given the potential for incoming bodies to have velocities many times greater than the fastest missiles and projectiles operable in Earth’s atmosphere (over 100000 m/s vs. about 100), and the potential for radar stealth, an effective defense system would have to be a “defense in depth cloud” of networked sensors, launchers, and self-guided missiles. I suspect that destructive long-range lasers will not be suitable for this application.

[Moontanman]

We already have theater laser missile defense that works quite well, one working prototype mounted in a 747 is deadly accurate. solid stat lasers that can shoot down artillery and defend aircraft as small as fighter planes are in the prototype phase. True the anti ballistic missile defense is somewhat less than accurate but the smaller scale defense lasers are already out there and very good at what they do.

[Boerseun]

I think the argument raised in a few posts in this thread regarding the exponential rise in human numbers as an argument in favour of expanding our presence to space is erroneous.

First of all, it has been shown throughout the world that as a given population's level of wealth and advancement rises, birth figures drop. Also, it has been estimated that our population would top round about 10 billion, reach a plateau, and then taper off.

I also think the argument that humanity will eventually destroy Earth, is faulty. Sure - we would destroy species left, right and center; but that doesn't mean it's bad for us. After all, when it comes to human survival, species have only two functions on Earth: To be delicious, and to fit well. We might eventually pave every square centimeter on Earth, and the only rainforests left might be purely tourist attractions, but we will survive.

As far as the eventual destruction of humankind goes, a big enough rock might do us in. But I think it will be much more profitable and practical in the long run to expand our data inventory of asteroids, and a mapping of their orbits, and coming up with plans and means of deflecting or destroying them when they seem to cross our path and crash into Earth. If asteroid deflection/destruction technology is not in our means yet, it's surely just over the horison.

I'm not shooting orbital colonies down - they might very well be cool and awesome. I'm just of the opinion that if we do get around to building them, we will build them purely because of that - the coolness and awesomeness factor. They will not make a dent in Earth's population figures, at all. They also will not make a sure guarantee for the species' survival in case of a big rock slamming into the Earth, because whether we build colonies or not, asteroid deflection/destruction technology will still be vigorously pursued on Earth because of the high population figures there.

If the Earth is destroyed, and you have a handful of colonies somewhere in the Solar System as the only survivors, you have a species supremely adapted to an environment that doesn't exist anymore. I fail to see the point. We should pursue machine intelligence, and be done with it. They will be our offspring, and they will not require "colonies". They will be perfectly capable of surviving under an extremely wide range of conditions.

Machine intelligence is the natural next step in evolution. And yes, I did say "natural". Humans, are after all a species just like any other. Our technology, our pollution, our greatness and our weaknesses, are all products of Nature. If our brains (given us by mother Nature) let us come up with a self-replicating machine which can store data and be intelligent by current standards, why would that be unnatural?

We want to build colonies for us, because we naturally assume that we are the end product of evolution. We have to save humankind by whatever means possible. Imagine if all Australopithecines reasoned that way.

We have to get rid of our chauvinisms. And building colonies to protect a species which is simply as transient as any other evolution came up with over the last 3 billion-odd years is just one of them.

Humans are, however, the first species to be in a position to transcend flesh and blood. And that should be pursued with all means available, before the next rock hits us.

And I'm not talking the "transplant-your-brain-into-a-machine" tripe, I'm talking the creation of an independent, intelligent machine which can be said to be an individual intelligent being on own merits, not having someone's "brain" in it to guide it.

That is what we should be doing. And that will be our legacy in the Galaxy. Billions of years down the line, after the sun's death, millions of machines will be roaming the galaxy, singing humanity's praises. They are also the only imaginary way of crossing the vast chasms between galaxies.

Oh well... off-topic to the n'th degree. I apologize. Maybe I should blog about this.

[TheBigDog]

I think it is fair to say that taking on projects that will require global resources and construction efforts that may span thousands of years is evolution from our current state. The assumption that we can do this in a single generation or within the lifetime of a person needs to be examined.

Bill