[modest]

Originally Posted by CraigD

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!

It was the Phalanx I was talking about. One of the few things in this world I have inside information on My buddy who just got out of the navy was a phalanx operator.

Originally Posted by CraigD

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),

I think our fastest missiles are a bit quicker than a Cessna and 100 k/s would be one ridiculously fast meteor. But, your point is well taken.

-modest

[Moontanman]

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.

Expanding into space would not lower the numbers of humans on the Earth, if I gave the impression that this was the idea of colonization i apologize. We are reproducing much faster than any conceivable transport off the earth could keep up with.

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.

We already have far too many people on the Earth. the only reason the number of people we have can be supported is that the majority live in poverty. I'm not sure i am comfortable living on an Earth with no room fro anything but people. To allow animals to have their own parts of the earth and support humans at a reasonable level we would have to cut the numbers of humans we already have

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 rain forests left might be purely tourist attractions, but we will survive.

The whole idea behind save the Earth is to save the wild areas and the animals that live in them. I think it would be sad to live on a planet where the only animals and wild ecosystems were in zoos and parks.

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

.

It might be possible to deflect an asteroid of reasonable size that we already know about. Rouge asteroids and large comets are the real danger. A large asteroid coming unexpectedly at a high rate of speed would be impossible to stop or deflect. Then you also have things like super volcanoes and continent wide lava flows, not to mention widespread out gassing of methane cathrates from the sea bed. These methane deposits are probably the most dangerous part of global warming. If even a small percentage of these deposits were released due to warming sea temperatures it would be devastating to the earth's ecology. The worst mass extinction of complex life was thought to be due to this process. the longer humanity keeps it's eggs in one basket the more likely that basket will be upset.

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.

There are purely economical reasons to have colonies, zero gee manufacturing, non polluting resources, aneutronic fuel, orbiting power plants. there are reasons other than the simple cool factor.

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 If the Earth is destroyed, and you have a handful of surviving under an extremely wide range of conditions.

The survival and flourishing of living humans is what i see as important. machine intelligences are not human and are not part of this discussion, at least for me.

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?

This is a mater of opinion, i don't see machines as anything but our tools. machines would not be human nor would they have human motivations or maybe even any motivations all. If nothing else i think it's important to save and maybe even spread the genome of the Earth. machines do not count as life forms for this porpoise.

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.

I think humans can evolve further but not if we stay on the earth. eventually there will be many species of hominids again. isolation in space colonies and by distance will assure this.

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.

Yes we are transient but we can still evolve biologically, there is no pinnacle of evolution.

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.

Only flesh and blood is capable of having human motivations, machines would not necessarily have any motivations at all. yes i am a human or flesh and blood chauvinist. what is the point of having machines if we are not around?

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.

I would much rather humans be there to prove those praises by actions, a galaxy full of machines seems pointless and sad.

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

It would make a good blog and everyone is entitled to their wishes

[Thunderbird]

Moonman, Even if all your dooms day senerio's came true it would be much cheaper, easer, safer, logical,sustainable, just to build these structures on, or in the earth.

[Moontanman]

Originally Posted by Thunderbird

Moonman, Even if all your dooms day senerio's came true it would be much cheaper, easer, safer, logical,sustainable, just to build these structures on, or in the earth.

How so? Where could you put a a hundred square miles of land on the Earth were it would be isolated from the environment for a thousand years and be invulerable to the very things that made it nesesarry?

[Thunderbird]

Originally Posted by Moontanman

How so? Where could you put a a hundred square miles of land on the Earth were it would be isolated from the environment for a thousand years and be invulerable to the very things that made it nesesarry?

There is no more hostile environment than space, not to mention isolated from all the things needed to survive. If you had to build contained systems they would be much easer to build on earth.

[Moontanman]

Originally Posted by Thunderbird

There is no more hostile environment than space, not to mention isolated from all the things needed to survive. If you had to build contained systems they would be much easer to build on earth.

Yes space is hostile, but not the space inclosed by the colony. All the things you need to suvive are already in the colony or within easy reach. Think of it as living in an isolated U shaped valley that simply curves up and around on it's self. The isolation is a good thing, you can not only move it to avoid big problems but unlike an isolated area on the Earth, problems outside your colony cannot bring you down. There is no way a self contained area on the Earth could be prepared before time to be in an area that wouldn't be affected by what ever bad thing had engulfed the rest of the Earth.

[Thunderbird]

Originally Posted by Moontanman

Yes space is hostile, but not the space inclosed by the colony. All the things you need to suvive are already in the colony or within easy reach.

easy reach on earth, if your on earth,
Imagine building then sending out a fleet of space craft to land on mine and retrive just water, not to mention all the 1000s of things that cannot be gotten in space. The logistics compared to doing the same thing on earth would be a thousand times harder. Even if the earth failed to support life in the biosphere it still would be a treasure trove of the basic's needed to support an encloser on earth.

Originally Posted by Moontanman

Think of it as living in an isolated U shaped valley that simply curves up and around on it's self. The isolation is a good thing, you can not only move it to avoid big problems but unlike an isolated area on the Earth, problems outside your colony cannot bring you down. There is no way a self contained area on the Earth could be prepared before time to be in an area that wouldn't be affected by what ever bad thing had engulfed the rest of the Earth.

Isolation is a very bad thing in this case there are to many things that can go wrong, and in a finite space those many things would also be contained in the finite space. Murphy's law cannot dissapate, it will dissamate all things in the finite space. You cannot bottle a biosphere it will quickly decay. There are to many interconnections in an envornment, its a global system.

[Moontanman]

easy reach on earth, if your on earth,
Imagine building then sending out a fleet of space craft to land on mine and retrive just water, not to mention all the 1000s of things that cannot be gotten in space. The logistics compared to doing the same thing on earth would be a thousand times harder. Even if the earth failed to support life in the biosphere it still would be a treasure trove of the basic's needed to support an encloser on earth

.

A colony would not need the earth for anything except people and eventually not even that. These colonies would be built from materials at hand not from imported "dirt" from the Earth. there is nothing that cannot be obtained from space. Water, hydrocarbons, "dirt" what would you need from the Earth that couldn't be obtained from nearby asteroidal objects?

Isolation is a very bad thing in this case there are to many things that can go wrong, and in a finite space those many things would also be contained in the finite space. Murphy's law cannot dissapate, it will dissamate all things in the finite space. You cannot bottle a biosphere it will quickly decay. There are to many interconnections in an envornment, its a global system.

You talk as though there will only be one tiny colony always on the verge of disaster. there will be hundreds, thousands, maybe, eventually, even millions of these colonies. They will be absolutely big enough to be stable environmentally, needing only the occasional addition of things lost to space. You cannot seem to wrap your mind around this concept. a space colony will not be like the tiny greenhouse in the desert experiment, they will be thousands of times bigger and the people inside will be able to bring in outside materials and to tweak any of the environmental parameters to suit.

[Moontanman]

Space colonies would not only allow groups of humans to avoid natural disasters they would also allow groups of humans to evolve societies separate from the whims of Earth based tyrannies. No doubt tyrannies would develop in some of the space colonies as well but other types of societies would develop too. Trade with the Earth would be important in the beginning but eventually the colonies themselves would establish their own economy based on trade between each colony and even based on the building of new colonies. Places like the Lagrange points of Jupiter could support the building of thousands of colonies and the materials to support their continued well being. Something as simple and easy to make as metal foam could cause a new industrial age on the earth. So could things like zero gee bearings or pure very large crystals. Such things would make the colonies very important to the earth and allow the colonies to flourish. It's difficult to predict what would be important in the future but industrial products from space will no doubt be important to the earth as well as to the colonies.

[Pyrotex]

Always look for basic assumptions. Then look again.
MoontanMan has logic on HIS side if we must depend on "rockets" to expell reaction mass to lift the megatons we will need per colony.
ThunderBird has logic on HIS side if we don't.
The alternatives?
1. space elevators. Not just 1, but hundreds strung along our equator, each lifting 10 to 100 tons per week.
2. lift the materials from the Moon, which has only 1/6 the gravity. Better yet, use rail guns to "shoot" the raw materials into Lunar orbit.
3. teleportation. No, NOT Star Trek style stuff, but at the atomic level. It just may be possible to teleport simple small atoms at near-zero Kelvins. If we can teleport cryogenic hydrogen and oxygen atoms (rocket fuel!), then you can easily use rockets to orbit the Queen Mary stuffed with all the cargo she will hold. Hell, you can orbit entire prefabricated sections of your colony.