How long before our civilization reaches Type I, Type II, Type III civs

[Reaper]

Assuming we don't blow ourselves up first, how long do you think it will take for our civilization to reach a Type I, Type II, or Type III civilization (on the Kardashev Scale)? What type of technological capabilities would you expect such a civ to have, or have solved? What type of issues/problems do you think these civs will run into (anything ranging from technical to political ones...)? And, how do you think we will get our civilization to those milestones?

 

This is intended to be a very open-ended discussion, so don't worry about details. I just want to hear your honest opinions.

[Pangloss]

I'll let you know.

[jimmydasaint]

Very interesting question. IMHO, even before we try to harness energy from the Sun, economically developing civilisations will go to war against each other to harness the dwindling carbon-based energy resources. This power-play will keep us pegged to te first stage. This is a simplistic notion but we can debate this point. I will propose that China will come into conflict with the West at some point in the future.

[bascule]

I don't think it's easily predictable.

[SkepticLance]

The probable answer is never. The classification of civilisations into Type I, II, and III is just one man's idea of what might happen. We have no actual scientific evidence that this classification has the least bit of validity whatever, or even that it is technically possible to tap the entire energy of just one star.

 

My own view is that we will become independent of stellar energy totally. In theory, deuterium can be used as an energy source via nuclear fusion. The amount of deuterium just here on Earth is enough to keep humanity going for billions of years. And the probability is that there is vastly more in space. The rings of Saturn alone must contain many Earth's worth of deuterium.

 

Why would a highly advanced species tie itself to stars at all, when it can load up on the universe's abundant deuterium and travel to anywhere it wants?

[Mr Skeptic]

I kind of agree with SkepticLance. Portable power will be very useful. However, there is no way we would let all the energy of the sun go to waste. It is highly probable that in the far future, we will either utilize most of the energy of the sun, or put it out and mine it for hydrogen for portable power. I think we will use the sun for powering stationary space habitats of some kind (possibly like a dysonsphere). Portable power will be very useful mainly to things that want to move around -- spaceships. Using the sun as a power source is highly advantageous, as there is no loss to maintain the fusion reaction going, nor potentially expensive containment system to maintain.

 

As to when, I have no clue. We still need some time to study, catalogue, and preserve samples of most life on earth (very valuable information for medicine, genetic engineering, etc), before we should even try at becoming a Type I civilization. I'd say not less than 200 years. Also, we would likely bypass the Type I civilization completely, and start working on being a Type II civilization instead. Why mess up our favorite planet, when there is so much more real estate in space, and it might even be cheaper (thinner materials, 24 hour sunlight, no storm damage, no tree-huggers).

[jimmydasaint]

We are making some serious assumptions here about technology and that we will still be around to harness solar energy and deuterium energy. Heck, even right now the West is staring down Iran so that we can monopolise its oil reserves. Although China have the Shanghai Cooperation Organisation as a source of energy at present, eventually it will move from using coal to oil and when that happens.... conflict. IMHO we have roughly 50-100 years to develop alternative technologies to harness energy but most of the renewable sources are too dilute to support the current lifestyle of the West. Just an opinion...

[SkepticLance]

I have always had a bit of a problem with the concept of a Dyson sphere. It has the same drawback as Larry Niven's Ringworld. That is, you cannot physically anchor a structure to a star, since it is just too damn hot. And a ringworld or Dyson sphere does not orbit. It cannot. It sits in space independently of its parent star. Without some means of changing its position dynamically, it is only a matter of time before the star moves through the sphere, creating massive destruction, before moving off into space, leaving the sphere to die.

 

It would be much easier and safer to establish millions or even trillions of habitats in space, orbiting the star. The orbit would keep the habitats safe. And those habitats are potentially mobile. If there is any problem, they can move off and join another star.

[Sisyphus]

Technically, a "Dyson sphere" is just anything which intercepts all or most of the radiation from a star. A "Dyson shell" is the hollow sphere of solid matter, and it's got all kinds of problems relative to other methods. Gravitational instability, as SkepticLance mentions, is one, as is the ridiculous required structural strength, and the fact that you somehow have to build the whole thing at once. The wikipedia article about them goes into some detail, although it doesn't offer a lot of specific numbers.

 

If there ever will be a Dyson sphere (and it shouldn't have to be said that that is one enormous if), I'm guessing it would be "built" over a very long period of time, and consist of an ever-increasing swarm of orbital objects, be they habitats or collectors/reflectors. Type II civilizations aren't built in a day...

[Sayonara]

The probable answer is never. The classification of civilisations into Type I, II, and III is just one man's idea of what might happen. We have no actual scientific evidence that this classification has the least bit of validity whatever, or even that it is technically possible to tap the entire energy of just one star.

Depends if the definition is strict enough to require that the entire energy absolute of the star is harnessed, or just the usable energy which the star emits.

 

My own view is that we will become independent of stellar energy totally. In theory, deuterium can be used as an energy source via nuclear fusion. The amount of deuterium just here on Earth is enough to keep humanity going for billions of years. And the probability is that there is vastly more in space. The rings of Saturn alone must contain many Earth's worth of deuterium.

But "millions of years", in what we must imagine would be a civilisation which is expanding and become technologically, politically, and economically more complex, will rapidly shrink as an inverse function of population size and device power requirements. History shows that tying oneself to a single power source is neither strategically wise nor economically viable.

 

Why would a highly advanced species tie itself to stars at all, when it can load up on the universe's abundant deuterium and travel to anywhere it wants?

Such a species is unlikely to have a singular will. As with any complex civilisation you wish to name, this civilisation will be affected by financial inequity, political boundaries, the vagaries of local and civ-wide trade rules, weird by-laws, border restrictions, taxation, and so on and so forth. A completely homogenous pan-galactic reliance on one source of fuel and one habitation philosophy is magnificently unlikely.

 

And a ringworld or Dyson sphere does not orbit. It cannot. It sits in space independently of its parent star. Without some means of changing its position dynamically, it is only a matter of time before the star moves through the sphere, creating massive destruction, before moving off into space, leaving the sphere to die.

I think there is a danger we might drift off the topic here, as with the last thread which descended into a battle royale over static/mobile habitats. The questions which were specified in the OP relate to civilisations which have ascended or are ascending the Kardashev scale; not civilisations which don't qualify. Those questions are:

 

• What type of technological capabilities would you expect such a civ to have, or have solved?
  
• What type of issues/problems do you think these civs will run into (anything ranging from technical to political ones...)?
  
• And, how do you think we will get our civilization to those milestones?
  

 

To some degree the issue you raised about a ring or sphere not being a true orbital structure falls into the category of the second question. But it's a trivial and contrived objection: clearly an effort to build any such structure would take that problem into account, so it will never physically arise.

 

BTW, the "millions of habitats" idea you describe was Dyson's original "sphere" concept. Popular fiction has given us the idea of the solid sphere, which always causes some confusion. Conventionally we now use the term "Dyson Swarm" to differentiate the original multi-habitat concept. I suggest we adopt that convention in this thread as necessary to avoid confusion.

[SkepticLance]

Sayonara said :

 

"But it's a trivial and contrived objection: clearly an effort to build any such structure would take that problem into account, so it will never physically arise."

 

I could not disagree more. This is the science forum. If we see something implied that is essentially contrary to the laws of physics, then it should be mentioned. And to assume that an advanced civilisation will magically find a way to get around those laws is a complete cop out.

 

If we assume 'Dyson sphere' equals 'Dyson swarm' then we have a solution that does not go counter to the laws of physics. Perhps we should follow that line.

[Sayonara]

I could not disagree more. This is the science forum. If we see something implied that is essentially contrary to the laws of physics, then it should be mentioned. And to assume that an advanced civilisation will magically find a way to get around those laws is a complete cop out.

Well, you are saying one or the other of two things here. Either...

 

1) It's impossible to build a solid Dyson sphere because it cannot be moved to compensate for the star's motion, or

 

2) A civilisation which was sufficiently technologically advanced enough to build such a sphere will somehow have a blind spot to this engineering requirement, despite it being so obvious that our primitive monkey brains can quite easily see it, and would end up crashing into the sun.

 

Since (2) is so ridiculous, I presume you mean to state (1). Is that right?

 

I am not sure why you think that a solid sphere is "contrary to the laws of physics". The fact that something cannot sit in orbit does not require it to go against the laws of physics in order to exist, it just needs to be engineered such that it is capable of -- and these are your own words coming up -- changing its position dynamically.

 

You have got the cart leading the horse on this one.

 

If we assume 'Dyson sphere' equals 'Dyson swarm' then we have a solution that does not go counter to the laws of physics. Perhps we should follow that line.

If you like. I notice that you had absolutely nothing to say on my replies to your deuterium post. You know; the on-topic parts of my earlier reply.

[Reaper]

The probable answer is never. The classification of civilisations into Type I, II, and III is just one man's idea of what might happen. We have no actual scientific evidence that this classification has the least bit of validity whatever, or even that it is technically possible to tap the entire energy of just one star.

 

I think you are referring to a Dyson Sphere, not necessarily a civilization. The Kardashev Scale is nothing more than a framework and is based entirely on how much energy an advanced civilization would need to consume in order to do what it does/could possibly do, sort of thing. Granted, it's not the best scale, but if you have something better we would like to hear it.

 

My own view is that we will become independent of stellar energy totally.

 

I do have objections to that claim. While I don't doubt we will have fusion power sometime in the future, I'm going to have to side with Sayonara here, in that it is probably not the wisest thing to do.

 

Why would a highly advanced species tie itself to stars at all, when it can load up on the universe's abundant deuterium and travel to anywhere it wants?

 

Well, given that stars can provide virtually limitless amounts of energy (well, for as long as the star is alive), that might be one good reason for doing so. Second, being near a star system means that you can also ensure a steady flow of raw material necessary to maintain habitats and civilizations (i.e. iron, water, etc).

 

 

If there ever will be a Dyson sphere (and it shouldn't have to be said that that is one enormous if), I'm guessing it would be "built" over a very long period of time, and consist of an ever-increasing swarm of orbital objects, be they habitats or collectors/reflectors. Type II civilizations aren't built in a day...

 

According to Freeman Dyson, it's gonna be a million year long project . All we have to do is provide our descendants with the proper motivation .

Edited July 6, 2008 by Reaper
multiple post merged

[Sayonara]

I think you are referring to a Dyson Sphere, not necessarily a civilization. The Kardashev Scale is nothing more than a framework and is based entirely on how much energy an advanced civilization would need to consume in order to do what it does/could possibly do, sort of thing. Granted, it's not the best scale, but if you have something better we would like to hear it.

To be fair to Lance, I believe that when he made that comment he was imagining a civilisation which in its entirety is approaching level II on the Kardashev scale. That is how a Dyson structure could be relevant to this discussion.

 

What I don't get is why he thinks that while the enclosed star travels around the core along with all the rest of the matter in the galaxy, the Dyson shell is going to maintain an absolute position in space. But that has nothing to do with this thread, so meh.

Edited July 6, 2008 by Sayonara³

[SkepticLance]

Sayonara said :

 

"Well, you are saying one or the other of two things here. Either...

 

1) It's impossible to build a solid Dyson sphere because it cannot be moved to compensate for the star's motion, or"

 

Actually, I think I overstated a position in my previous post. I should say sorry for that before continuing. Sorry.

 

My comment about the Dyson sphere is that it would be really, really difficult to move it as needed. A Dyson sphere would have to be of a mass that is truly astronomical. At least that of our entire solar system (excluding the sun). To figure out a way of moving that mass, even to the most minor degree, would be essentially not possible based on our current understanding of physics.

 

Indeed, if you were able to push the sphere at one point by, say, a million kilometres, the response elsewhere in the sphere would be largely to stay put while the sphere deformed to a very minor extent. How to move an entire sphere weighing as much or more than our solar system is a problem that has no current solution, unless there is some breakthrough in physics beyond our present understanding.

 

My alternative suggestion - that civilisation will become dependent on space habitats powered by deuterium - has the advantage that it does not require any new and magical physics. In theory, it can be done using an extension of what we already know. The biggest difficulty will be making fusion power practical, and that should be achieved within the next 100 years.

 

The amount of deuterium probably available in the cosmos should be sufficient to outlast the main sequence of suns in our galaxy. That statement is based on 2 assumptions.

1. Water elsewhere also contains about 1% of its hydrogen as deuterium.

2. There is as much water in other solar systems as in our own.

I suspect these assumptions are very valid.

 

In terms of social development, the concept of trillions of habitats permits a wide variety of social set ups. Each habitat might have a million plus people, and would be essentially an independent nation in its own right. While there would be trade, communication, and people swapping between habitats, each could still develop its own way of life, political philosophy, economic system etc. Any time a habitat nation decides its cannot live with its neighbours, it can just strap on its ion drive rockets, load up with reaction mass, and cruise off to another star system.

 

Perhaps humanity's distant future will involve a truly astronomical number of habitats cruising between the galaxy's solar systems, with vast numbers forming Dyson swarms around popular stars.

 

Sayonara said :

 

"What I don't get is why he thinks that while the enclosed star travels around the core along with all the rest of the matter in the galaxy, the Dyson shell is going to maintain an absolute position in space. But that has nothing to do with this thread, so meh."

 

Obviously both star and sphere are going to travel in the same direction at approximately the same velocity. It is the approximately bit that is the kicker. There is no physical connection between star and sphere, and thus they travel independently. We are talking about a structure that is designed to last a million years plus. There will be small differences in direction and velocity that will mean the relative positions will change. Given enough time - disaster!

Edited July 6, 2008 by SkepticLance

[Sayonara]

My comment about the Dyson sphere is that it would be really, really difficult to move it as needed. A Dyson sphere would have to be of a mass that is truly astronomical. At least that of our entire solar system (excluding the sun). To figure out a way of moving that mass, even to the most minor degree, would be essentially not possible based on our current understanding of physics.

But we have to take into account that such a structure would not be designed and built with our current understanding of physics.

 

Indeed, if you were able to push the sphere at one point by, say, a million kilometres, the response elsewhere in the sphere would be largely to stay put while the sphere deformed to a very minor extent.

I tend to agree. The solution, which is obvious to a monkey-brain so a Dyson-builder will probably also think of it, is to provide thrust at more than one point. In any case, since the sphere would be just as subject to the orbit of the galactic core as any other matter you wish to name, only minor adjustments should be necessary.

 

How to move an entire sphere weighing as much or more than our solar system is a problem that has no current solution, unless there is some breakthrough in physics beyond our present understanding.

I would imagine many, many, many such breakthroughs will occur between now and that far distant day when we dare even to contemplate what kind of materials we might best use to begin sketching the system that will allow us to design part of a Dyson structure.

 

My alternative suggestion - that civilisation will become dependent on space habitats powered by deuterium - has the advantage that it does not require any new and magical physics.

Magical physics is not a requirement for technical engineering feats. New physics is not going to be in short supply over the next 500,000,000 years. Fusion power might even be obsolete before your envisaged civilisation emerges!

 

However, the biggest single objection to your deuterium-fuelled galaxy is that territorially expanding populations do not homogenise. They adapt and radiate.

 

Perhaps humanity's distant future will involve a truly astronomical number of habitats cruising between the galaxy's solar systems, with vast numbers forming Dyson swarms around popular stars.

Quite possibly so. Sort of a romantic image, isn't it?

 

Anyway, Dyson shells (solid spheres) and swarms are only relevant to the thread if we are discussing a Kardashev-II civilisation. The deuterium/fusion civilisation does not qualify anywhere on the Kardashev scale, so we are off-topic with that. Let's get ourselves back on track!

Edited July 6, 2008 by Sayonara³

[Reaper]

Obviously both star and sphere are going to travel in the same direction at approximately the same velocity. It is the approximately bit that is the kicker. There is no physical connection between star and sphere, and thus they travel independently. We are talking about a structure that is designed to last a million years plus. There will be small differences in direction and velocity that will mean the relative positions will change. Given enough time - disaster!

 

But the matter around the solar system is also going at the same speed relative to the stars around the galactic core, so any corrections or maneuvering that has to be made will be relatively minor. In fact, it will probably be harder to build it then it will be to actually control it once it's built. So, I'm not sure why you don't like the Dyson swarm/sphere idea.

 

And, you also have to keep in mind that any civilization, no matter how advanced, will always have the same basic wants and needs, of which include security, and I don't think the deuterium/fusion mobile civ will provide much in the way of that...

[SkepticLance]

To Reaper

 

There is no such thing as a minor adjustment to something as massive as a Dyson sphere. Imagine the sun spits out a massive flare (there is no such thing as a 100% stable star) and the force moves the sphere off centre by a few cm per second velocity. Now you have to stop its movement relative to the parent star. How are you going to do that?

 

You suggest I do not like the Dyson sphere/swarm idea? Actually, I am neutral to either option emotionally. However, I like to look at the practical realities, in the light of modern science. Sayonara suggests that physics will change massively. Perhaps. But for the purposes of debate within this forum, it behooves us to stick to what is known. Otherwise we are writing fantasy.

 

From the practical viewpoint, in the light of known physics, I cannot see a Dyson sphere being practically possible. However, a Dyson swarm is eminently possible. I also think it is a more secure way of life. A Dyson sphere is very vulnerable to disaster - both natural such as an exceptionally large stellar flare, or manmade such as an H bomb attack. A Dyson swarm is much less vulnerable to both due to the ability to move habitats and get out of the way of the problem.

 

Anyway, if we regard a Dyson swarm as a Type II civilisation, we should be able to calculate how long it would take. Due to the mobility of habitats, it will happen simultaneously around many suns. Possibly around each and every star in our galaxy. If we assume that a space habitat can travel at 0.1 c, which is possible theoretically based on current physics, then a trip to the opposite end of the galaxy will take 700,000 years. Human reproduction is quite fast enough to over-populate the entire galaxy in less time than that.

 

Thus, the time taken to set up Type II civilisation (Dyson swarms) around all the suns in our galaxy, and using conservative assumptions, will be somewhere between 1 and 10 million years.

 

PS - I realise that this future civilisation is not really a Type II, and in some ways is approaching Type III - but if you assume my model of Dyson swarms and travelling space habitats is real, then it is probable that progress will not go I to II to III, but will do all three kind of simultaneously. In other words, the distinction loses meaning.

Edited July 7, 2008 by SkepticLance

[Sayonara]

There is no such thing as a minor adjustment to something as massive as a Dyson sphere.

"Minor" means that the adjustment is small compared to the diameter of the sphere. It's a matter of relative proportion. It might be a million-kilometre push in one direction, but that is still less than a 0.3% correction.

 

A Dyson sphere is very vulnerable to disaster - both natural such as an exceptionally large stellar flare, or manmade such as an H bomb attack. A Dyson swarm is much less vulnerable to both due to the ability to move habitats and get out of the way of the problem.

 

This is disingenuous at best. Shell or swarm, both have their effective surface at the same distance from the sun as the Earth, so none are any more or less vulnerable. Habitats could not move out of the way of flares, because they would be hit before they had time to respond - this is, of course, assuming a particularly well-aimed flare with a destructive range of at least 1AU, and a completely defenceless habitat (). The advantage of the shell under disaster conditions is that it is a big enough boy to take a serious beating and still be habitable to a human population in the order of 3x10¹⁸.

 

An H-bomb attack might do serious damage to a habitat, but not a sphere. The most powerful nuclear detonation ever triggered by man had a fireball radius of 4.6km, and I imagine a blast radius of about 50km beyond that. That is not even noticeable compared to the inner surface area of a shell, which would be about 600 million times that of the Earth's surface.

 

There are some really good objections to the shell conjecture, but none of these are they. I personally find a swarm much more likely, for all sorts of reasons, but I have to say that the objections you have raised so far are the most trivial. Compressive strength of a point on the shell under an arbitrary number of domes of 1AU radius with the gravity of the sun is a good objection. So is gravitationally neutral inner surface. "I can't imagine the technology responsible for building such a structure ever doing it well" is not an objection.

 

Let's just stick to swarms for type-II civs, it's easier, relevant, and we will agree more.

[SkepticLance]

Sayonara said

 

"Habitats could not move out of the way of flares"

 

Solar flares consist of hot ionised gas rushing out from the sun. They have to cover 150 million kilometers to get to Earth orbit, which takes quite a while. Warning travels at the speed of light, and even with today's technology, we get warning 20 to 48 hours ahead of a flare. In our Dyson swarm civilisation, we can expect even more than that, and a chance for habitats to move out of the way. If that is insufficient time, then there is no reason for the habitats to swarm at 1 AU. They could orbit further out and get more warning. This would even permit more habitats in orbit. It would be easy for an advanced technology to compensate for lower energy flux with more collectors.

 

Sayonara also said

 

"An H-bomb attack might do serious damage to a habitat, but not a sphere. "

 

This statement is based on the missile hypothesis, and is used today by the military as an excuse to spend megabucks on developing anti-missile defenses. If I were a terrorist wanting to explode an H bomb in Washington, I would not deliver it by missile. My delivery vehicle would be a battered old Volkswagon Kombi van.

 

If an H bomb attack were planned against a Dyson sphere, the individuals perpetrating that atrocity would get more impact by dismantling the bomb and reassembling it inside the sphere. It would do serious damage all right. In fact, it is worse than that. A highly advanced technology would likely have anti-matter bombs!

 

Also said by Sayonara

 

""I can't imagine the technology responsible for building such a structure ever doing it well" is not an objection."

 

The problem is that if you carry that view into a science discussion, you end up discussing science fiction, or even fantasy. If something is theoretically impossible today, we cannot simply assume that advanced physics will find a 'magical' way to do it tomorrow. I think it is valid to postulate advanced technologies that are marginally possible in theory only. However, to postulate advanced technologies which are theoreticaly impossible by today's understanding .....well why not postulate a magic wand while you are at it.

[Reaper]

This statement is based on the missile hypothesis, and is used today by the military as an excuse to spend megabucks on developing anti-missile defenses. If I were a terrorist wanting to explode an H bomb in Washington, I would not deliver it by missile. My delivery vehicle would be a battered old Volkswagon Kombi van.

 

If an H bomb attack were planned against a Dyson sphere, the individuals perpetrating that atrocity would get more impact by dismantling the bomb and reassembling it inside the sphere. It would do serious damage all right. In fact, it is worse than that. A highly advanced technology would likely have anti-matter bombs!

 

So, what exactly is the problem here? As Sayonara pointed out earlier, a Dyson Sphere is enormous. Even if we do assume that this hypothetical civilization has found a way to mass produce antimatter bombs, you are still talking about a preposterous amount of antimatter need to actually do any serious damage to the sphere. And that's assuming all of the energy of the blast goes into attacking the structure. Perhaps a brief introduction to "How to Destroy the Earth" will demonstrate just how difficult destroying superstructures will be....

 

Also said by Sayonara

 

""I can't imagine the technology responsible for building such a structure ever doing it well" is not an objection."

 

The problem is that if you carry that view into a science discussion, you end up discussing science fiction, or even fantasy. If something is theoretically impossible today, we cannot simply assume that advanced physics will find a 'magical' way to do it tomorrow. I think it is valid to postulate advanced technologies that are marginally possible in theory only. However, to postulate advanced technologies which are theoreticaly impossible by today's understanding .....well why not postulate a magic wand while you are at it.

 

Perhaps you did not take heed to Clarke's three laws, especially the third one: "Any sufficiently advanced technology is indistinguishable from magic". The point is, IF a Dyson Sphere is technically possible, it sure as hell won't be built with our current understading of science, or engineering; it will be built according to their understanding. You also have to understand that a lot of what we do today was considered impossible just merely 100 years ago. Certainly, much of our technology is based on science that was not known by 19th century scientists. For example, it was once said that mankind would never get to the moon because of the perposterious amount of gunpowder necessary to do so. Needless to say, we did it in 1969, based entirely on science and technology that was unavailable to earlier generations.

 

Anything that a Type II or a Type III civilization can do will most certainly be so much further ahead of us in terms of knowledge of what is possible and what is not. And they will certainly do things that we would consider hugely impossible. Of course, that is the point of the Kardashev scale; since we cannot guess at what "magical" technologies they might possess, we can certainly look at the energy demands of such a civilization, since as the more advanced (technologically, politically, socially, etc) a civ is, the greater their energy demands. HOW they can meet those demands is the point of this thread. There is no reason to expect that it is technically impossible to build a Dyson Sphere at all, maybe impossible to us, but probably not to a civilization like the one you see in Star Wars, or the one in Asimov's Foundation novels, or Larry Niven's Ring World civilization.

 

 

Basically, one of the aims of this thread is to speculate on how long, and in which ways, and how likely, we can go from this society, to being able to build something more like this, or this, or this

Edited July 7, 2008 by Reaper

[SkepticLance]

Sayonara said :

 

"Even if we do assume that this hypothetical civilization has found a way to mass produce antimatter bombs, you are still talking about a preposterous amount of antimatter need to actually do any serious damage to the sphere."

 

The discussion of relative security stems from a comment made earlier by Reaper about that. I was pointing out that a big target is actually less secure than a smaller one, and that mobility is also a defense. However, that is getting sidetracked. I suggest we leave the security question, as it is really unimportant. We all know that, if there is a nasty bastard who want to kill people, there is no 100% security.

 

Re Clarkes Law.

 

Yes, I am familiar with it. You should remember that Clarke was a scifi writer. His laws are also scifi. They are as much science as Asimov's laws of robotics. Which is to say : not at all.

 

We are supposed to be discussing science. I am happy to speculate, which can be a lot of fun. But I think we should limit our speculations to science. That is : we should not assume future sciences that can do what is now impossible, even in theory.

 

 

My original point is that I doubt we will ever build a Dyson sphere. And we do not need to. As has already been pointed out, they are not necessary for Type II civilisations. In fact, if future development follows the Dyson swarm idea, there will be space for even more people than you can fit into a Dyson sphere. The swarm is essentially unlimited in number. The only limit is matter and energy resources. And a mobile habitat can access energy sources other than solar.

[bascule]

The first question I'd ask is: where do you get the mass to construct a Dyson sphere? From the star itself?

[D H]

The first question I'd ask is: where do you get the mass to construct a Dyson sphere? From the star itself?

No. A Level II civilization almost certainly will use Unobtanium.

[Mr Skeptic]

The first question I'd ask is: where do you get the mass to construct a Dyson sphere? From the star itself?

 

Quite possibly. I know I'd make my dyson shere out of carbon, which should be present in the sun.