Hardly an insurmountable hurdle. We've done it once, with old technology. We're talking about new technology. Technology improves at an exponential pace. This is not a solid objection.

Unless you're trying to build something in space, in which case, mining from a planet takes a huge amount of energy to transport into space, due to Earth's gravity well. Better to mine from an asteroid and transport to a desired orbit. The energy required to handle this can be harnessed easily from the sun, either using solar sails or solar collectors and ion propulsion (which we already have a prototype for).

Another alternative, which my argument does *not* rely on, is some form of cheap transport into space, such as a space elevator or a launch loop or a launch ramp or a space gun. There are lots of options. However, that's only sufficient for initial mining, and in relatively small amounts. It will still be very expensive compared to mining an asteroid. Maybe we'll develop an orbital station using Earth-mined resources, but later on, we'll want to send out ships to the asteroids for their resources.

Dyson forest is far easier to accomplish than terraforming. It requires less technology and less up-front investment. The only tech needed is self-replicating biospheres. This is far more plausible than massive atmospheric generation projects which would need a huge energy investment and many years to get anywhere close to a sizeable atmosphere.

In the mean time, you would have to invest in self-replicating biosphere technology *anyway* to maintain bases on planet surfaces to keep the terraforming machinery running.

But we already know we are not 'average'. The Earth is the only planet in the solar system with signs of life. That already stuffs the 'we are average' assumption. If we were average, we would expect life to be everywhere, as it is everywhere on our planet.

I want to re-iterate a common myth. The old saying goes "Absence of proof is not proof of absence." The key word is 'proof'. Not 'evidence'. Unfortunately, a common myth about this saying has transformed it into "Absence of evidence is not evidence of absence." However, that morphed version is wrong.

If you expect to find sand in a box, and you look in the box, and there's no evidence of sand, then the fact that you looked and didn't find anything is evidence that there's no sand in the box. Now, maybe there's a few grains hidden in one of the corners. So, you look closer, but still no evidence of sand. This is still stronger evidence that there's no sand in the box. The closer you look, the stronger the case can be made.

We've looked for life in our solar system. Not everywhere, but in some places that we might expect to find it. No evidence. Clearly, there's no evidence of thriving life, or intelligent life. This is clear evidence that there is no thriving or intelligent life in our solar system.

My argument about not seeing space-faring life is the same way. Such life, if it existed would rapidly fill the galaxy. The galaxy is my box. I'm expecting to find lots of sand in this box, if there is space-faring life besides us. But we look, and we see no sand. No radio signals of any kind, no patches of missing stars (which is what the whole Dyson sphere idea is about; an advanced space-faring life form would tend to grow to absorb most of its star's visible light), no space ships flying about in our own solar system, no visitors, no nothing. Since we might expect to see it, and we don't, this is evidence that there isn't any in our galaxy.

Granted, we don't have the resolution to look very closely, but we can be sure that advanced life has not permeated the entire galaxy. The better we get at looking out there, and if we still don't see anything, the stronger the case can be made that we are indeed alone, at least in this galaxy.

As for the 'we are being experimented on' hypothesis: It's an idea for a sci-fi story, but it's an unfalsifiable hypothesis. You can always imagine that the aliens are even more advanced and even more clever that "Really, they're everywhere, but you just can't detect them in any way." Much like God on that count.

Then clearly, I was not addressing you.

Obviously I'm still not talking about you, then.

Life is just about life, it's not about "better". We'd be spreading life, but not necessarily to benefit anything else. Given the size of the universe, we'd just be moving mass around, really. Despite my rant, I don't have a problem with that. But to expect that we'll all-of-a-sudden turn into something we're not is quaint, but not probable.

I've heard the word "consumerism" used for it, too, but let's be honest: it's an extension of life. Life tries to get away with what it can while it can, and it only stops when it can't get away with it any more. It's just that our energy until recently has been limited, so we find ourselves in a unique period of history where we can do all these things that could aid in our downfall, and technological advancement (in terms of consumer goods) is still our focus.

The only real teacher is limitation.

You mean before the sun fizzles out? That kind of inevitable?

Sustainable is a wonderful word. In your mind, try this experiment: create a human population that uses its resources sustainably. Energy would be limited to available solar: wind, hydroelectric, geothermal, tidal, etc. Food would be limited to that which can be produced using naturally arable land, without the use of Green Revolution technology (i.e. petrochemicals). The population would be limited to the amount of food that could be produced (as food is energy), just as it always has been, and transportation would be considerably different.

To get to there from here, what kind of death toll do you figure would have to occur from starvation? What kind of mass migration out of deserts would be required? What energy source would take us even to the moon, much less farther? Energy is the key to all of that, be it in the form of food, or in the form of fuel. What do we do for energy, how much is available, and how can it be stored? That will determine what we can do, not anything else.

There have been estimates of 100 years, 1000 years, or even 10000 years for Mars to become a habitable biosphere.  There other details such as correct gas percentages.  Do all plants produce the same proportion of waste gases?

Wait... didn't you say this was out at the asteroid belt?  Do you know how much less sunlight there is out there?  Uranus isn't a frozen ball of gas (49K or so) for nothing.

Mars already *has* an atmosphere. It's just thin, and comprised mostly of CO2. Calculating how long it would take to get a good mix of oxygen propagated throughout the planet is simply a matter of figuring-out how much oxygen each plant will produce and getting a good estimate on how much of the planet they will propagate through / how quickly.

No magic / future tech / huge expenses required.

*Shrugs*

True.  I'm not saying that it's impossible, just harder than landing on a planet.

Well I thought about it, and if you do the right things, it will be a LOT easier to haul ore and such.

Space elevators require a transport ribbon (the thing the elevator rides up) to be extremely strong and flexible.  Stronger than steel.  For the initial mining stage other methods would be more economical.

I have no idea what a Dyson sphere is, please explain.  Sorry for my ignorance.

Well I can't argue with you there.  

I will now predict that my first use of the quote feature will be a failure.  

Hmmm... got me there.  I admit I was thinking of the Kuiper belt, not the asteroid belt.  The asteroid belt is past Mars.  Mars has very little atmosphere, and reaches daily high temperatures of around -51F, and has even once reached a balmy -23F, if Wikipedia is to be believed.  If less sunlight is getting filtered by Mars' puny little atmosphere, that suggests that significantly less solar radiation is hitting Mars than Earth, and that's just about where the asteroid belt starts.

And you're going to grow food there, right?

So I suppose you know of magic drilling machines that are going to harness this energy for free?  I'm confused.  Why are you even mentioning this?

You're forgetting the main reason Mars is so cold. Lack of greenhouse effect. Earth has all sorts of greenhouse gases. Mars is limited almost exclusively to CO2. Its atmosphere is just too thin to hold in much heat.

But at an asteroid, you would have an artificially insulated environment. With enough insulation, it only takes a small amount of energy to maintain a decent temperature. Next, what you need is the right wavelengths and quantity of light to support photosynthesis. The wavelengths are fine, and if Kevin is correct about the amount of light at that orbit, then it seems growing plants wouldn't be so hard after all.

Even if the amount of light is weak, you can just deploy bigger collectors and generate the right kind of light to grow plants. Obviously, in this case, you would have to trade off energy for growing plants against energy for mining.

However, my scenario involves setting up an economy of trading energy for material resources. Energy can be transmitted from close-orbit biospheres to distant-orbit biospheres with various kinds of beam transmission. The mining camps would use this energy, and send back material resources with solar sailed transports.

We don't have to manufacture anything. We take simple organisms already adapted to living in harsh conditions (antarctica, for example, where some forms of plants are known to extract water from permafrost), put them on a probe and send it to Mars (fuck, even just incidentally include them on a probe that's headed there anyway).

What's so tough about that?

Reproduction with modification to meet the demands of the pressures ofthe new environment, in theory, will take care of the rest for us as surely as gravity takes care of anchoring our buildings to the Earth.

Honestly, the future can take care of itself. Unless the life extension crowd and/or the post-humanists have anything to say about that, I don't have to live then. If I am alive then, that will be the time to worry about much of this. What matters today is to solve the problems of today.

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One of the first things that we need to deal with is the coming energy crisis. It if fully unrealistic to expect that the petroleum mega-projects of today will still be viable in 30 years time. I can't see how we can bring new energy technologies on line fast enough to be able to avoid new petroleum mega-projects.

So yah, ANWR, the continental shelves and methane hydrates are simply going to have to happen. Those, of course, are CO2 producing technologies and we can't be still relying on them a century from now. At least not unless we deal with carbon sequestration but the science on that is not on a solid foundations yet.

While those are going on, we also need to beef up out nuclear capacity and the electrical transmission system. One interesting idea that is still in the laboratory stage is the development of “super cable”, basically superconducting cable for longer distance runs with liquid hydrogen as the cryo-fluid. Then we have both electricity for our houses and hydrogen for cars and trucks coming into out cities.

Along with that, I would love to see us put the real work needed to develop renewable power technologies for those places when it would be appropriate to deploy them. Solar Power in the dessert, wind power on mountain tops, geothermal in valleys and other ideas. Just don't expect more out of them than they can reasonably provide.

Renewable power simply cannot be the cure to all of our ills. It can however be a low cost form of power that can provide some percentage of our basic energy needs. Perhaps 10 to 20 percent of that in some places.

Actually, a friend of mine from another forum has a very interesting project going on. He found some start-up company that thinks that it can build solar cells on a level sufficient for industrial deployment and the venture capital to start the company. He did a deal with them where he gets some percentage of the first production runs for free to set up demonstration projects. He is using that to create solar farms for military bases in Arizona and New Mexico. The last time that I heard from him on the matter, he had his first base running on about 25% solar power.

Many more projects like that in different areas of renewable energy should get the ball rolling for the rest of us to start thinking about how such things could be usefully deployed.

Then, apparently, if ITER works the way they think (an experimental fusion reactor in France that should be capable of producing as much power as it consumes and will be operational quite soon), then in the 30-50 year time frame, we maybe able to use fusion here on Earth.

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As far as space travel is concerned, again, let's take small steps and see what they can add up to.

For example, SpacEx,Virgin Galactic and a few other companies are working on bringing the costs down quite a bit. I would imagine that there simply must be a cost floor for standard rocketry but NASA, the Russians and so on are doing huge, inefficient bureaucratic space programs. So apparently, there is quite a bit of money being spent that really is not needed.

Then too, there is the Ansari foundation which is working to provide silly prizes to encourage those who have the resources to think about space flight. Scaled Composites spent a good deal more than they got from the first X prize and they have only reached the flight capabilities of about the first couple of Project Mercury launches. Yet, they spent a good deal less (in inflation adjusted dollars) than NASA spent for similar results.

Then too, the cost reductions are already at the point where one of the teams working on X prizes is being led by John Carmack, the video game developer. Sure, he is one of the rock stars of the video game world and as rich as Croseus from his work but even so, that should indicate where we are at as a species getting ready to think about space in a larger context.

Heck but the Ansari foundation has a section of their web site set aside for anyone who feels like dropping by to write in suggestions for future X prizes.

The prize that I suggested was the development of rocket engines that could be used not to get into space but rather for commercial semi-ballistic travel. Basically, the system would be a conventional aircraft up to about 30,000 feet and then become a ballistic missile from there. Using even reasonably conservative inputs, speeds in excess of 5,000 mi/hour are easy. That would make the world a much smaller place.

Then too, it has potential to get us into space. There is a concept of a transfer orbit, which basically is so elliptical that such a station would dip into the atmosphere every time. Not so deep as to have to worry about skin heating but close enough that a smaller craft from a semi-ballistic jet could perform a conventional rendezvous. A transfer station would need frequent re-boosting to keep it in orbit but that would be a pittance of a cost compared to putting it up in the first place.

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All of the above is based on existing science and technology and the capital requirements range from tens of millions to hundreds of millions of dollars. The time frame is spread out over about 50 years. So we certainly can do it. Or some of it, or something else that I have missed.

As I noted above, the futurists from 50 years ago turned out to be quite wrong and I don't think that they have any monopoly on wrong guesses. Even so, I hold some cautious optimism that it is at least possible.

A good one?  You're the one who just got onto me for predicting anything a thousand years out, and as I survey the world for the last 1000 years, I notice that not even countries can be counted on to look remotely similar, much less corporations or government agencies.  And yet... somebody's going to spend trillions of dollars to send a spaceship out with absolutely no hope of realizing any gain for a thousand years.

I think it's a very good argument.

I'm interested in people.  I'm fascinated and aggravated by how much people want to believe this claptrap.  The arguments themselves are inane.

I hope I have clarified your misunderstanding of my argument.

Because it's clear people care about the fate of future generations a thousand years from now.  Right.

No, it's ludicrous to think the craft would ever be launched.

Show me a ten trillion dollar time capsule, please.

You mean those pyramids that their sons could look at and say, "LOOK WHAT MY FATHER DID!"  Yeah... no material gain  at all.

Seriously Natural, get your head around this, ok?  You know about the hypothesis of R (degree of relatedness) being the primary measure of altruism.  We do things for our kids and our grandkids, and occasionally nieces and nephews, but for the most part, the only people we will really make sacrifices for are our children.  Name me the last human project that was designed to have absolutely no gain for anyone for (let's make it easy) a hundred years.

Ahem...

You've been reading something written by the White Man, methinks.  No serious anthropologist has found anything approaching a noble savage, and that includes the Iroquois.

I don't know you well enough to guess, but for most people, it's a combination of a couple of things.  People have a vague anxiety about the future of the earth because their cave-man brains simply can't imagine a thousand years.  The only two ways to deal with it are to dismiss it out of hand or treat it as we would something a lot closer.  That's why you get a lot of talk about environmentalism and very little action.  People feel somewhat guilty for dismissing it out of hand but they can't help being creatures of this moment.

Science nerds, I imagine, just want to see neato ray guns and transporters.  I'm an evolution geek, so I'd like to see what humans evolve into if we survive, or what the earth would look like in ten thousand years, but I really don't care either way if humanity survives.  Call me callous, but I am not a humanist.  I don't think humans have any inherent value above that which we ascribe to ourselves, and giving yourself medals is just nuts.  I believe that's why it's easier for me to look at the facts about human nature and see that neato spaceships might be neat to think about, but they're next to impossible for humans to practically achieve.  I mean, hell.  We don't even really care about going to the moon anymore.  Yeah, Mars is awesome, and the Shrub tried to drum up excitement about a manned mission.  (LOOK AT THE MONKEY!  LOOK AT THE MONKEY!  911!  TERRORISTS!)  But the fact is, only scientists are interested, and they aren't known for having ten trillion dollars to blow.  And that's just Mars.

Horse shit.

If you had that much money and blew it all on a rocket, you'd be publicly hanged, buried, dug up, drawn and quartered, buried, dug up and cremated, and your ashes would be sent on a rocket to the sun.  Think of how many billions of lives you could change right now!  Ok... I grant that maybe a few people with ten trillion dollars to blow might blow it all on one place, but sending a rocket to another star takes thousands of people, and lots and lots of red tape.

Notice how all of your arguments rely on things like "If the world was made of cream cheese and apple jelly" and mine are "Since people are the way they are"?

(Cough)  Yeah.  Nothing like summer on Ios.

Because everybody who did all those things was alive at the time.  People don't do shit they don't get to gloat over, and even Rocket Man's own descendents a thousand years from now will probably be debating whether or not he really existed, or whether Jesuhammed or Aliens sent the message from the stars.

Nor will I.  Might as well argue about whether a tenth level Paladin could kill a young white dragon.

I read that.  I thought it so ludicrous that it was self refuting, so I didn't bother.  I've dealt with it before, though.  You know enough biology to know how incredibly stupid this idea is.

Inventing technologies again?  You are happy to jump in with me when I'm bashing a theist about not understanding consciousness, and then you turn around and suggest that not only do you understand it, you understand it well enough to know that we're going to create it in machines and then assemble it from scratch in the depths of space.

Right.  There are few AI guys I know who would like to know your secrets.

No.  I never said all the physics was implausible.  I wrote all that to clarify that I meant collectively, not individually.  I feel confident there is a scientific solution to at least one of the ten thousand problems with deep space colonization, whether it's done by sending people or sending magical people makers.

No, it's more like "Since all the solutions involve imagined technology, and all of the possible scenarios defy human nature, I still think it's never going to happen."

I can't help but notice that the only person here with the actual physics knowledge to address this agrees with me.

But our biology and mental makeup is essentially unchanged. We still have the same emotions, drives, etc. When we read Plato, we see where he was mistaken, but we understand his motivations. It is, after all, motivations that are the key to whether or not future people will send out a mission.

I notice you snipped out all the other relevant examples, and cherry picked the only two you could make a stab at refuting. I'm rather disappointed you're using such tactics.

You have *not* refuted the resource argument that I've made, and so appealing to a 'ten trillion dollar' time capsule is not a refutation. It assumes that the resources will be scarce compared to the entire resources being harnessed.

But any ballpark figure reveals that the energy available in space is mind-bogglingly enormous, and the investment required from a well-populated solar system to send out a mission is mind-bogglingly tiny in comparison.

And the same "Look what my father did" can be used to support sending out the first mission to Alpha Centauri. The launch itself is an accomplishment that people can be proud of. All you have to do is put in enough redundancy to give the mission a decent chance of success, and you have your bragging rights.

Voyager 1 and 2. The benefit is miniscule to humanity. If you want, we can attach some scientific instruments to the mission and it can relay some data back about its travel, revealing secrets of the interstellar environment.

There's your expensive time capsule. We've already done it.

So, you're letting your personal apathy colour your view of other people. A lot of people *do* care if humanity survives.

I'm not a humanist either. But I'm not apathetic.

In my view, it is not 'humans' per se that is valuable, it's intelligence. We just happen to be the most intelligent species on the planet at this time. And of course, the value is not inherent.

You're talking about apathy. People are not born apathetic. They have their enthusiasm beat out of them, largely by the education system, followed by corporate consumerism. Apathy is not something we are stuck with either. It is possible, as I've proven to myself in the past 4 years or so, to regain hope and enthusiasm and wonder.

People, in the US especially, have had their hopes beaten out of them. Bush is a prime example. Huge approval ratings at the beginning, followed by the lowest ratings of any president ever. And you guys elected him twice! WTF.

But anyway, this is just proving my point. When you lack a vision of the future, the future looks glum. When you lack intelligence (not you, but the general populace), you lack the ability to envision the future. You also lack the ability to make good choices about the future (like not figuring out that Bush was an idiot until after electing him twice), and so the future ends up being shitty.

It's no wonder to me that it's the scientists who are enthused about space. They can envision it. They (e.g. people at NASA) have worked out the theory, and they see it is at least plausible. Carl Sagan absolutely saw the possibilities, and was very enthusiastic about changing things down here so we could do wonderous things up there. Do you think he was just blowing smoke up people's asses? No. He was trying to inspire them. Trying to communicate his vision. Trying to show them the real possibilities.

Why are we down on Mars? Because we've had Bushes and Clintons for the past 20 years. Because we've let science education go to shit. Because we've lost our vision. Because we've dumbed ourselves down.

But it was *40* years ago that we got to the Moon. *That* was expensive. *That* was pushing the envelope of technology. If we had the vision we had 40 years ago, Mars would be a piece of cake. Just get off our asses and do it. Even in this shitty economy, it could be done (a tiny fraction of the military budget, for example).

Your argument is an Argument from Complacency. An Argument from Apathy. An Argument from Beaten Down Imagination.

"People everywhere and for all time will be as uninspired as I am, therefore it's not possible."

People everywhere are *not* uninspired. There are *always* people willing to dream and hope for the future. And with that, I'll resurrect the examples you snipped out:

Why did the 300 fight off the Persians? Glory.

Why do people put money in trust funds for their kids education? Hope.

Why do they leave inheritances behind? Legacy.

Here's a few more:

Why do rich people start scholarships for kids that are not related to them, and they'll never meet?

Why did Nobel start his Prize such that it would continue long after his death?

Why do people (like Copernicus) have their most treasured books published *after* their death?

Just because *you* cannot imagine yourself being motivated to do things like this, doesn't mean nobody is.

Resource argument. You still haven't addressed the obvious fact that in a populated solar system, the fraction of resources required would be tiny.

The biggest speculation I make is in self-replicating biospheres, which is hardly implausible, considering advances in manufacturing, robotics, and biotech.

And people are not the way you think they are. You're projecting. You're looking at the world through shit-stained glasses. Wipe that shit-bias off your glasses.

That's not a counter-argument.

The 300 died in their fight. The rich benefactor leaves the scholarship in his will, *after* he's dead. Nobel is no longer alive. Copernicus had his book published after his death.

I'm sure there will be a big celebration and lots of gloating when the first humans send the first colonization mission to AC. They don't have to wait 1000 years to party. See, they have this thing called 'vision of the future', which 'inspires' them. I wonder if you've ever heard of these things?

Easily. And that's not a counter-argument.

I know enough about biotech to know that we're well on our way (e.g. artificial wombs, animal cloning, robotic manufacturing, etc.), and there's no theoretical barriers to stop us.

I've already stated numerous times that my argument doesn't depend on machine consciousness. I do however think it's plausible to speculate about, and so I think it's worth mentioning.

I understand it enough to know that it is a purely physical, informational process, which could, in plausible theory, be implemented on a different substrate than biological neural tissue. Read On Intelligence by Jeff Hawkins, or search YouTube for some of his lectures. We are getting closer and closer all the time.

Kurzweil presents a good case that the hardware will be able to support it if we can develop the software. Hawkins makes a good first stab at plausible software. Brain scanning resolution in both space and time is improving exponentially, such that we will soon be able to map out the functions of individual neurons, giving us the hope of developing a working theory of human cognition from 'cell' to 'mind'.

DG is a biologist, not a physicist, and he hasn't addressed the argument regarding populating the solar system, which is key. I too have taken physics at the university level. I'm more inclined to trust the real astrophysicists, such as the people at NASA, and *they* already have three or more plausible interstellar scenarios, according to *their* standards.

The only major technology my proposal requires is self-replicating biospheres. All the other stuff, handling radiation, propulsion, etc., will all be worked out naturally as the solar system becomes populated. It's like, once you have a working internal combustion engine, and people start making cars, all the things like wheels, shocks, chassis, drive, air bags, etc. will all be worked out through trial and error. Once you've got automobile technology working on Earth, it's relatively easy to pick and choose innovations to design a Lunar or Mars rover based on automobiles.

No, this is not part of my argument. I've always said 'assuming we don't blow ourselves up first'.

The original post was about whether or not there's extraterrestrial life out there. I made the argument that even if there is life, there is no space-faring life in our galaxy besides us. The argument I made there was about how once you get space-faring, you quickly get to self-replicating biospheres, which colonize a solar-system, and from there it's a short step towards colonizing a whole galaxy. Based on this argument, and the lack of a galaxy filled with ETs, we can draw a pretty high probability that there are no space-faring ETs out there.

That has now morphed into a defense of *human* capability of populating the solar system and colonizing the first star. But I've always, throughout this discussion, maintained the necessary assumption 'assuming we don't blow ourselves up first', which means, 'assuming we survive long enough to develop self-replicating biospheres'.

So, here's my argument in a nutsehll:

Assuming: We survive on Earth long enough to develop self-replicating biospheres in space.

P1: There is a huge amount of energy and material resources available in space.

P2: Self-replicating biospheres will undergo evolution in the form of replication with variation over many generations.

P3: Self-replicating entities tend to fill up all available niches from which they can draw energy and material resources.

P4: If we could send out an interstellar colonization mission with comparatively low resource cost, we would.

C1: The solar-system will rapidly fill up with a variety of biospheres, harnessing a huge amount of energy.

C2: Based on this pool of energy and technology, it will be relatively easy to develop an interstellar craft that re-creates a self-replicating biosphere at another star, beginning the process again.

C3: The cost of such a mission, as compared to the total amount of energy harnessed by a populous solar-system, would be comparatively low.

C4: Since we could, we will.

Again, the conclusion depends on the assumption, as I've always stated in this discussion. If you want to say the assumption is unlikely, that's a different debate. That's a debate about changing social conditions down here. But it's only a debate to the point that we survive long enough to develop self-replicating biospheres in space. Once we've got those, the assumption is no longer needed; Earth could blow up the next day and we'd still reach Conclusion #4.

The only part that I see as tricky is the technological feasibility of self-replicating biospheres. I think the trends in biotech and manufacturing are sufficient to draw the conclusion that it's plausible without invoking any magic.

My argument doesn't rely on that, as I've stated from the beginning. I only mention it because it is plausible to me and to others, such as Kurzweil.

My argument doesn't rely on such nano-tech either. More likely the nanotech would be related to materials, such as the nano-tech we already have today. Really, nano-tech is not a significant component of the argument. The closest you could argue is biotech such as artificial wombs, automated genetic engineering, etc.

Who said *anything* about isolation? The solar system would be *full* of people. There will be tons of communication with people on Earth and in other biospheres. And the biospheres themselves will probably house 50-150 people, if not more. Like I said, such issues will be worked out once the first biosphere replicator begins the process of technological evolution.

There will be all sorts of different kinds of biospheres. There may be some that are large, and in stationary orbits, holding up to 300 people or more. They could be solar-collector stations. There could be some that hold 10 or fewer people for short trips, shuttling material resources around from place to place. There could be an Earth-bound orbital station holding thousands of people. Biospheres may rendezvous with others, swapping people, transporting people from one location to another.

In any case, there will not be any isolation from human culture. We already have a world-wide internet, and you know personally that you draw a significant amount of human interaction from it. There can easily be a solar-system wide internet. While people are beaming energy from place to place, they can easily beam information along with it. While there may be some minutes' delay (up to 10 hours at Pluto's orbital distance), we already know how to deal with latency in our communication, via email, YouTube videos, webpages, wikis, etc.

So, we'll be tied into Solar culture, able to watch movies, listen to music, etc., and we'll have small to medium sized groups for one-on-one contacts, intimate relationships, etc. The only 'isolation' will be the kind of isolation human tribes have experienced and handled well for hundreds of thousands of years.

We have a pretty good idea that optimal tribal size is about 150-300 people. If we can achieve biospheres approaching those populations, we will be able to handle psychological problems easily.

As for the mission to Alpha Centauri, that's easy. Just grow more than one human at a time. After the first generation, who will be raised by didactic robots and computers, and will have human interaction with the other kids, then all future generations can be raised by human parents as usual. They will have full access to Solar culture via their own local copy of the internet. And at Alpha Centauri distances, they can participate in the Solar internet at a time lag of 4-8 years. Meanwhile, they will be developing their own stellar civilization with their own local internet.

Again, these technologies will be developed during solar-system population, and packaged up for the interstellar mission. No need to postulate a huge up-front investment.

It won't be the inhabitants of Earth, it will be all the inhabitants of the whole solar system, which may well exceed the population of Earth.

And it won't be 'scrounging'. The Sun puts out 4x10^26 Watts. If we only harness 0.000005% of that, it will be 1,000,000 times as much energy as humanity's current entire energy consumption (which is approx 2x10^13 Watts).

There is a *shitload* of energy in space. This is not a question of energy resources. If there is energy and material to be harvested by self-replicating biospheres, they will replicate. That's all that matters.

The amount of energy required to send 1000 tonnes at 0.01c (including deceleration) is only on the order of 1x10^19 Joules. Let's make it a round 1x10^20 Joules. Assuming the solar system harnesses 0.000005% of the sun's energy, and we tax this energy economy a mere 0.01%, it would take a grand total of..... 13 hours to generate the required energy for the trip.

All it takes is self-replicating biospheres, and the solar system fills up over time, and nature does the rest.

How long would it take the solar system to fill up? Let's say your biosphere can harness on average 1 MegaWatt, and takes 20 years to reproduce. To get to 0.000005% of the sun's output, you would need 20 trillion biospheres. With a reproduction time of 20 years, that would take 883 years.

Give or take. These are very conservative estimates. Will it really take 20 years to replicate a biosphere? Probably less. Will they only be able to collect 1 MW? Probably more. Do we really need to harness 0.000005% of the sun's output? Probably less. Is the Solar culture only willing to be taxed 0.01%? Probably more. Do we need to have the time so short as 13 hours? Probably longer.

Will it really take 883 years? Probably less.

I repeat. There's a shitload of energy out there. All we need are self-replicating biospheres, and the rest is just a matter of time.

We can already freeze sperm, eggs, and embryos. No need to make humans from scratch. We are already working on artificial wombs. We already know a lot about emotional, psychological, and cultural needs of kids as they grow. We can develop technologies to raise babies no problem. There is nothing magical about this. We don't need nanotech.

It will be our cultural descendant, for sure. Biologically, if we really needed to, we could transmit a DNA sequence to the arriving craft, and have them grow whoever's children we want. But I think the cultural connection is enough.

They will absolutely have meaningful communication with Solar culture. There will just be a 4-8 year lag due to the speed of light. Humans have dealt with this kind of situation in the past, when it took years to send messages from one empire to another. This is no different.

We will share technologies. They will explore the new system and send us back information about it. We will bring them up to date on what has happened in the intervening 1000 years. It will be a very real connection.

They will be our Daughter Star.

Wrong to be a skeptic? Never. Lacking vision? That's curable. Bad counter-arguments? Yes.

Oops, sorry. Wasn't aware of that. I took advanced courses for physics, chemistry, and biology in first year, expecting to go into standard sciences, but switched to Computer Science in my second year. So, while I don't have a degree, I've got a pretty solid foundation in the main sciences. Also studied psychology and sociology, as part of my degree (Human Computer Interaction). Jack of all trades, master of one.

natural, you may be one of the reasons I have hope for the future. Enough people like you, and we'll be fine. It's too bad there aren't enough people like you. I'll explain.

Of course it does. More rapidly now than ever. But the behaviour of consuming everything in our path is a real hurdle. We're wired to consume everything we can. It only makes sense that we would. I desperately hope you're right, and we can work together on this. Failing that, I hope we go through our energy resources quickly enough that we can't bring total extinction to the seas, and toxicity to the air and soil.

Well of course.

Absolutely. We just need to get everyone on board with the plan, and change the electrical grid system from a centrally powered system to a distributed system. If we could do that, it would solve a ton of problems right off the bat.

Hey now - you don't need to go all nanotech. All you have to do is re-vamp the mindset. If people got used to things like solar-collector-powered refrigeration, we could set up the world with cheap air conditioning. No problem.

I'm hoping that in 20-40 years, we will have exhausted our cheapest oil and gas reserves, and will be forced to abandon mechanized warfare. That could do it.

Booo! More research reveals that liquid hydrogen is terrible as a fuel. The best way to store hydrogen is in nickel-cadmium canisters. But even that sucks. Flywheels, my man. High-speed flywheels. Even NASA likes them. Reducing the transmission of power would also a big win. As would removing the tendency to convert energy from one form to another all the time (like electric to kinetic and back).

I love it! (K, now I'm not really being sarcastic, I'm enjoying your optimistic enthusiasm.) Those are both extremely tall orders, but I agree that education is of inestimable benefit. Eliminating poverty is a very difficult thing to aim for, but no reason to not try.

Is it any wonder we get all the immigration?

Absolutely. I'm with you 100%.

I don't either. In fact, it's the focus of much of my life's work.

Right, but that's not a limit. I'm saying we are limited in our power to blow ourselves up by the energy we have access to. The amount of energy we have access to is always our limit. It's always the limit of all biological entities.

That's why I have great hope. If we can't afford the oil any more (in energy gain versus energy spent) then we will be limited in our destructive capacity. I believe that this will happen soon, and our environment will be able to recover from our then newly-impossible over-consumption.

There are too many technical problems to overcome inregards to miniturizing a nuclear power souce. The biggest problem being, removing heat, if you don't remove the heat, you melt down. I've seen alot of the old research accidents they had when trying to make nuclear engines for jets and vehicles. It seems more often than not the most efficent/safe way to produce it as a souce of energy is just as a steam plant.

So about the aliens
Sorry I'm not even going to try to spell extra terrestrials
Well.
Maybe I did. But. That's not important
My reasoning behind my belief of their
Existence is that if however we were made happened
Here. Why couldn't it happen again somewhere else?
If by some SLIM chance there is a god.
Wouldn't he...it. Want to make this again?
Or maybe the big bang caused us (my personal belief)
And maybe it shot living particles some other direction
As well?
Just my thoughts

No you aren't mistaken, that's how the whole system works, heat transfer. The problem arrises with how fast you generate heat vs how fast you remove it. Air is a very poor heat removal method, which is what what a car or plane would use ultimately for a heat removal source. I'm just trying to state from what I remember reading up on past mistakes and experiments with nuclear power use for vehicles/planes. The ones I remember reading about melted down.

I think that nuclear power isn't the way for air or land transportation.

{edit}I'll probably have to go back and read some stuff, it's been about 9 years since I was in the field.

Actually, Russia and America have both already successfully tested nuclear-powered aircraft.

The only thing of concern for the engineers was actually radiation shielding (not heat).

Neato.

 Since this thread is dying, I just want to thank you all for having this debate.  It was a lot of fun for me and it's the first debate I've ever participated in, and of course I got royally schooled by a many of you.  Thanks.  :D

1. Extraterrestrial life.

Life stems from self-replicated chemical reactions. So it's a common feature in the universe. Life and "carbon life" is everywhere at mild conditions. Because of evolution life is very diverse. So, it's difficult for us to accept that some alien entity is, say, intelligent. I think forms of intelligence are more diverse that forms of life.

2. A Multiverse?

Let 'all that exist is the universe'. So 'other' universes don't exist by the definition. In other words if a multiverse consists of separate universes, which aren't linked by space-time paths, then all other universes don't exist physically because they cannot be detected. They cannot affect us. So a multiverse is an unsupported believe. If they ARE linked then they compound the universe.