Plot twist: the "dark matter" in the universe actually consists of Type III societies harnessing the electromagnetic radiation of their galaxies by a means as-yet unknown to us.
"A fire upon the deep" by Vernor Vinge is an interesting exploration of this. In the book different (and more desirable) physical laws take effect in places of low average matter density, so intelligent civilizations migrate out of their galaxies into the sparsely populated galactic rim.
Well to be honest I found the Tines more interesting and so I'm glad he focused on them. But the zones of thought did strike me as a creative way to both solve the Fermi paradox and have space opera without otherwise breaking the rules of hard sci-fi.
Unfortunately, this idea has been explored and discarded. Thermodynamics requires the emission of detectable EM energy from such shells, just at longer wavelengths. We'd expect to see dark matter emitting in microwave or IR, but we don't.
Well, if you emitted it all in a beam away from the plane of your galaxy, that might make you very stealthy. That would impart thrust on the sphere... which if it wasn't perfectly balanced might cause it to wobble, and then start rotating...
... and now we have a sci-fi reason for quasars. :)
You could direct the waste in two beams perpendicular to the plane of the galaxy, in order to balance net thrust.
I question how stealthy that would really make you, though. If someone was bothering to look for stealthy civilizations, they'd just have to scatter some observatories around their region of the galaxy, then watch. Eventually, your structure would occult a star from the POV of one of those observatories, or they'd pick up your beam scattering in interstellar gasses or dust clouds.
Of course you'd need two beams. If you used a single beam it would be a stellar rocket... which might be fun in different ways. Certainly gives the phrase "interstellar warfare" a different meaning.
I realize this is all space opera, not hard SF. It's still fun.
I'm unconvinced by the Kardashev assumption that energy is the limiting factor for civilisation.
It's more likely that beyond a certain point you have all the energy you can use, and the limiting factor becomes collective intelligence.
I'd guess that in the same way that processors keep getting more efficient, so do civilisations. At the highest levels the energy signature of a civilisation is virtually indistinguishable from the cosmic microwave background - if it's observable at all.
My off-the-cuff response is that energy could be harvested locally in many places, but society as a whole will be bounded by the speed of communication (which might not exceed c). It's possible that too long communication lines will fracture society into separate "islands".
1. Advanced societies have probably solved the aging problem, leading to either extremely long lives or effective immortality. As long as these societies keep reproducing (and they will, unless they deliberately engineer out the urge to procreate, which I consider to be unlikely), they'll need space to spread out. Sure, they could probably pack themselves like sardines into a single solar system, but that only works if they'll be spending 100% of their time in virtual reality, and that would be begging the question.
2. A need for resources. Type III societies can capture 100% of the output of a star, but even this amount of energy might not suffice once society grows large enough. And even at that level it's still probably easier to manipulate matter than it is to convert energy into matter, so it'll be more efficient to harvest planets and asteroids and whatnot for raw building materials, which means leaving the solar system.
3. Even assuming they manage to create virtual reality that is 100% indistinguishable from reality, it's likely that there will still be a lot of beings that will reject the idea of living 100% in virtual reality simply because it's virtual. Even if it's indistinguishable from reality, they'll still know it's not real. So they may visit VR, but will want to actually live in the real world. Or in other words, humans have shown a tendency towards the perverse, and it's not unreasonable to assume aliens will too.
4. Any kind of scientific research still being done at that level will likely require the use of reality instead of VR. VR is a simulation, and even if it's indistinguishable from reality to your senses, it's still presumably not actually simulating reality down to the planck level (because it's part of the universe, it cannot simulate the entire universe at the same fidelity that the universe itself operates at, as that would presumably require more information than the universe contains), and so there's probably a fair amount of research at that level that simply can't work in simulation and requires testing against actual reality.
1. Advanced societies have probably solved the aging problem, leading to either extremely long lives or effective immortality. As long as these societies keep reproducing (and they will, unless they deliberately engineer out the urge to procreate, which I consider to be unlikely), they'll need space to spread out.
If they had as little agency around the issue of population control as you suggest, this makes me question their status as "advanced."
I did not suggest that they have little agency around population control. What I suggested was that aliens will continue to want to have children, and so space will be needed for those children given that the parents won't be dying any time soon.
Beyond that, if you have effectively infinite space and resources, there's no need at all to have even the slightest bit of population control. Population control is only necessary to ensure adequate resources (including space to live) for everybody. But when there's no constraint on resources, there's no reason why anybody shouldn't have as many children as they desire.
I did not suggest that they have little agency around population control. What I suggested was that aliens will continue to want to have children
So you suggested that their civilization as a whole had little agency around population control.
Beyond that, if you have effectively infinite space and resources, there's no need at all to have even the slightest bit of population control.
You're forgetting simple geometry. Space empires can only expand proportional to n^3, while their population could potentially expand proportional to k^n. Also, in a situation where there are multiple star-faring "species," a hegemonic, exponentially expanding entity might well be viewed by others as worse than obnoxious.
You're ignoring constant factors. Space empires will likely expand much faster than dictated by population needs, to the degree that, as it spreads out, it will presumably experience a reduction in population density. Sure, with multiple star-faring empires, there may be a limit to how far in space a given empire can expand, but a Type III society is capable of building all sorts of gigastructures, including ringworlds and dyson spheres, so even a moderate expansion out of a single solar system will provide plenty of room for population expansion. It's also likely that immortal or long-lived species will end up having a relatively low number of children (given effective immortality and complete control over reproductive capability, it seems likely that aliens will choose to have a low number of children over their lifetime and will likely wait much longer before having their first child, which means even a simple doubling in population will take place over a relatively long time).
Given these reasonable assumptions, it seems likely to me that most space-faring civilizations of this level of technology will never experience any kind of pressure on living space. If you've ever read the Culture series (by Iain M. Banks) then you might reasonably expect such a civilization to "Sublime" before running out of space. Or to eventually alter themselves so as to remove the desire to procreate in a deliberate move to "retire" from the galactic stage.
I said "most" because there is of course the possibility that some species comes along that has the urge not just to procreate but to have as many children as possible as fast as possible, and manages to achieve this level of technology without ever altering this behavior. Such a species that is driven to expand its population as fast as possible may then experience restrictions on living space, but such a species would eventually have to enact population control, which could take the form of altering themselves to remove this urge to procreate as fast as possible and therefore will become just like "most space-faring civilizations".
I am a big fan of The Culture. Also, it sounds like you just posited that advanced civilizations would effectively exercise population control, otherwise avoid shortages and avoid the necessity of rapid spatial expansion though technological means.
My belief is that advanced civilizations would naturally end up with what is effectively population control, without any actual active work towards that goal. As birth control becomes easy and prevalent, unwanted pregnancies stop happening. And it seems reasonable to me that, given greatly extended life span / effective immortality, people will naturally choose to wait longer before having children (if they have any at all) and will have relatively few children and/or will have a long duration between children. So this does pretty much amount to population control, without having any actual restriction on any given individual's ability to have children.
So this does pretty much amount to population control
From the POV of an outsider or a different species, would any entity care about the difference between "effectively/pretty much" and what you deem to be "actual" population control?
I doubt it.
So basically, you haven't been disagreeing with me, just splitting hairs on what the words "population control" means. I'm using a more generic criteria: Is the population controlled?
I think I'm drawing the distinction between "active population control" and "passive population control". I define "active population control" as anything where the goal is to control population and active steps are taken in that direction, typically with the effect of reducing freedom of individuals (e.g. a simple control would be "no more than 2 children per couple", which means an individual cannot decide to have 3 children). Whereas "passive population control" is basically where population growth ends up controlled as a side-effect of other changes, generally without any limits on the freedoms of individuals (for example, eliminating unwanted pregnancies would be a form of passive population control; the goal isn't to control the population but rather to eliminate an undesired situation, and no individual's freedom is curtailed, but the overall effect would be fewer children across the entire population).
There's a school of thought that says we're already in a virtual reality.
As I understand it, the argument is basically that, assuming true high-fidelity virtual reality is possible, then it's likely that any society that advances far enough technologically will eventually create a virtual world and populate it (or let it populate itself) with virtual beings that don't know they're in a virtual reality. Given this assumption, if you let the virtual reality run long enough, then the virtual beings inside the virtual reality will eventually end up creating yet another layer of virtual reality. Assuming this is possible at all, it then follows that there could be an effectively infinite number of virtual realities layered inside each other, and under those circumstances, it's extremely unlikely that our reality happens to be the outermost "real" reality but is instead somewhere in the stack of virtual realities.
because the holodecks can only show them what they already know and what they can imagine. the (mostly empty) universe can show them things they were not yet capable of imagining.
My speculation has for a long time been what I call the uniform cooling hypothesis. There are no type III civilizations because such things haven't happened yet.
If the universe is all the same age and if the emergence and evolution of life is tied to the overall thermodynamic evolution of the universe, then everything might be approximately of the same scale and complexity within a certain standard deviation.
If this is true then when we go out there we will meet all the others who have also just developed to that level.
Yes, but if someone is off by just one percentage point, then they're 13 million years ahead. There needs to be something so unlikely about sentient life, that it only arises approximately one at a time in each galaxy, or the Fermi paradox would apply.
This hypothesis works best if we propose an extremely narrow developmental range.
Of course since we have basically no data, we can't actually argue either way beyond vague hand-wavey speculation. You can't calculate standard deviation from a sample size of one.
In general, sub percentage point uniformity is taken as evidence of a very strong synchronization mechanism. The extreme uniformity of the cosmic ray background was taken as evidence of inflation, which is quite an extreme position, if you look at the numbers.
That such a synchronization mechanism should work with such precision over the entire universe seems very unlikely. Filtering would not require synchronization, so that seems much more likely.
The only way I can imagine it being that synchronized is if evolution itself is somehow tightly coupled to cosmic inflation.
Here's the speculation in more detail:
Evolution can be viewed as an information transfer mechanism that learns about the universe and transfers that information into the genome. (This is one interpretation found in evolutionary information theory.) As the universe inflates there is more total information in it, and therefore more information for evolution to learn. At certain points, a kind of information density "critical mass" is reached and phase transitions occur: the emergence of life, complex life, cooperative/multicellular life, higher order intelligence, industrialization and complex society, etc. Since the total amount of information in the universe is (we're speculating) tied directly to the arrow of time, this occurs simultaneously everywhere at approximately the same time.
Again this is hypothesis bordering on speculation since we do not know of any mechanism that directly couples information content to cosmic inflation like this, or even how we would go about measuring such a thing objectively. For instance it's not possible to differentiate between random and encrypted data using Shannon information measures, so what statistic would you use?
Then I'll invoke Occam's Razor. A simple filter explains the situation more cleanly, and doesn't need the addition of a wild-sounding mechanism that affects evolution that's attached to inflation.
Furthermore, if it has such a powerful and pervasive effect on evolution, why haven't we already discovered it in our studies of evolution to date? We live on a planet chock full of evolving life.
I think the Fermi paradox has a hidden assumption, that we are intelligent enough to detect aliens. We couldn't detect that the earth revolves around the sun till quite recent in our (genetic beings on earth) evolution. I say give it a few years, we'll figure out that aliens are too alien right now to us. Computationally speaking, our brains are quite limited, though we have recently gained the ability to share ideas across the internet. Nice hearing from you cousin!
I wonder what ants think of airports? Or what mice believe about tube trains as they scuttle under the platform.
We are separated from mice (or at least somewhat similar animals) by approximately 40m years of evolution, I think that the separation to a Galaxy altering level entity would be much more profound, and frankly we wouldn't understand what it was if it came and tickled us.
We are in no way separated by 40m years of evolution. Our common ancestor 'is'. That mouse you see today has been evolving just as long as you have, but with different priorities.
Technically yes, but practically the mouse reached a more or less standard form millions of years ago, in a local maximum, and we've been developing into all that we are mostly far more recently and represent a far more advanced form with lots of metrics (fitness to local environment is not the be all end all metric -- just the one evolution uses).
Hello - I said "somewhat similar animals" by which I meant very early primates who were a bit like squirrels and mice. I should have made it a bit clearer!
I did get the date wrong - I should have said 65my.
This isn't true for all species, it's (in a way) different depending on species. Your statement assumes that evolution is a constant, time-dependent process; it isn't.
For an example, I point to the horseshoe crab. We're separated by x million years of evolution from the horseshoe crab, because at some point there's a common ancestor. Its ancestor evolved to the horseshoe crab, millions of years ago, and then stopped. Meanwhile, our ancestor continued to evolve into us. The horseshoe crab is a prehistoric animal, a "living fossil". It hasn't evolved significantly in millions of years. This is quite different from mice.
Another example is the coelacanth fish; it was thought to be long-extinct as we have prehistoric fossils of it dating to the dinosaur days. Turns out it's still alive. Another less-extreme example is the shark: it's a little different than its prehistoric ancestors, but not much. I'm sure a biologist could point to a bunch of other species that haven't changed significantly since the days of the dinosaurs.
Mammals like mice have indeed been evolving just as long as we have, but many non-mammalian species have not.
I don't think societies/civilizations are a viable organization scheme on cosmic time scales. What if very advanced civilizations all reorganize themselves into symbiotic aggregations of less-than-wholly-individual entities? Communications between these entities inhabiting virtual reality is so fast that the aggregate seems like a hyper-intelligent hive mind to human-like sentience?
If we take mind upload as a given, then it should also be possible to create "clones" of our minds with ease. This level of technology will have a profound effect on the value society places on individuality.
"all" is usually the key issue with solutions to the Fermi paradox. We can certainly find reasons for any given civilization to go the other way, but it's more difficult to argue that all of them do.
There are very strong reasons to believe that all civilizations (multitudes of independent, individualistic semi-cooperating sentient creatures) are inherently chaotic and therefore unstable. There are loads of arguments as to why they are doomed to fail, or to try to expand exponentially. If we take a cold and realistic eye to technological civilizations, they do seem doomed to self-destruct or "sublime" into something incomprehensible. There aren't many examples in nature of things that are the confluence of two or more super-exponential processes that are long-term stable. (In our case, those would be population, energy use, and technological change.) In fact, I think there are basically none.
I think you take a particularly narrow view of what constitutes a "society". Arguably, current human society is the product of over 10,000 years of continuous development. Yes, there have been numerous changes in structure and power, but our fundamental "human" identity hasn't really changed in that time.
I would also argue that life itself has proven remarkably long-term stable on our planet. Granted, it has not been stable enough to produce a type-III society, but if we remove homo sapiens from the planet for a thought experiment, there exist other species that are developing communication or tool-use skills and might succeed us even on the technological path.
So my view is that, unless we continue to fail spectacularly, life will still continue without us. Even if we do not reach type-III, that does not necessarily preclude Earth from producing a type-III society in the future.
I think you take a particularly narrow view of what constitutes a "society". Arguably, current human society is the product of over 10,000 years of continuous development. Yes, there have been numerous changes in structure and power, but our fundamental "human" identity hasn't really changed in that time.
Sounds like you are the one who has a narrow view of "society," rather. In the abstract, it only need be something like "a multitude of cooperating but competing, independent self-preserving, self-advocating sentient interests." That's fairly abstract while still being a sure recipe for highly non-linear and chaotic effects.
Even if we do not reach type-III, that does not necessarily preclude Earth from producing a type-III society in the future.
But then you're setting up a situation where a series of chaotic and unstable arrangements snuff themselves out or flare-out in a puff of singularity-colored smoke, ending with the appearance of the first stable meta-societal form.
Could be great news- it rules out (within some limitations) most of the really bad paperclip-maximizer scenarios.
At least if society is doomed we'll only doom ourselves, and not the entire Milky Way! One takes what cheer one can get when pondering this sort of subject.
It means it won't take long after we are doomed. Singularity which can bring doom and eternal life comes at almost the same time. I would pick longevity over Singularity any time.
They call economics a "dismal science", but I find such attempts at 'astrophysics' (or whatever this and stuff like the Drake equation are called) even more dismal...
Tons of unknown variables filled-in with vigorous hand waving, ad-hoc and unproven assumptions left and right, etc, and some high school math thrown in for good measure...
I think you're taking a wrong look at this paper. This paper isn't actually about whether or not type 3 societies exist. This paper is about the fact that there appear to be no galactic clusters that show a particularly abnormal, greater, amount of electromagnetic emission than the known standard. Which, actually, I'm pretty dang surprised hasn't been searched for already. Then, in order to be a little whimsical and make sure the paper gets read, (s)he explains where they came up with the idea for this experiment.
Seems to me like a completely rationale thing to measure about the universe. Imagine if the result had come back true?
The "dismal science" thing has nothing to do with scientific standards. It was an expression coined and used by Thomas Carlyle in satirical essay in favor of slavery to refer to political economy because economist's support for emancipation.
As for the origin of the quotation yes -- but it has been used to talk about scientific standards in Economy ever since it was coined -- there are even a couple of books with that exact name on the topic.
This really tells us extremely little about advanced civilizations, beyond that we haven't seen them doing a few variations on a very specific activity—harnessing all the stellar radiation in their galaxy.
There are huge number of assumptions based on that idea. A fundamental one is that a civilization in a relativistic universe would grow to densely inhabit a galaxy. Another is that they would need that much energy. Another is that even if they did have need for that much energy, they'd bother collecting EM radiation from stars.
That third is an interesting one to me. Now, you could muck up the night sky for the entire Milky Way, or you could, with Sufficiently Advanced Technology (tm), annihilate a total of 10 Jupiter-masses a year across the whole galaxy. For your average star system, that's extracting energy from 1.1 billion kg of mass a year, or roughly what NYC's garbage collection services dispose of every two weeks.
Pondering that, I suspect it's the wrong idea to imagine that a very advanced civilization, something we can only understand in the dimmest sense, would be constrained by something as specific as stellar energy emissions.
> Another is that they would need that much energy.
Even if they needed that much energy, the best way to do that [that we know of] is to build a Dyson sphere. With every star shrouded by a Dyson sphere you no longer need to shroud the galaxy.
A more critical assumption is that a type III civilization even cares about masking its presence. If they were even worried about being attacked, the speed of light would mask their progress for a great deal of time and, because of the distances involved, even seeing them once the light reaches you would be a massive accomplishment - most likely you'd have to search for individual stars in another galaxy which are disappearing in unusual ways.
A type II civilization could possibly build a telescope with a large enough aperture but I assume that type II civilizations would be long past their ignorant warring ways.
Dyson's spheres have low long term fuel efficiency. They are better off destroying the stars and burning their fuel in fusion reactors. At least with our current understanding of physics.
Also, a civilization could have dimantled Andromida Galaxy 2 million years ago and can't tell yet. For more distant objects the gap gets rather wide.
Overall I think the main agreement here is that humanity is far too ignorant to even posit how a type III would operate - never mind figure out how to detect them.
Stars use different fuel than reactors. To fuse simple hydrogen, four nuclei have to collide at once. This is so unlikely that it requires a very large mass of fuel to sustain a reaction: at least the size of the Earth, according to one article I saw.
It's entirely possible to burn deuterium in small reactors but there's only about 1/2500 as much deuterium as hydrogen.
(Perhaps some unthinkably advanced civilization could figure out how to get energy from hydrogen fusion in a small reactor, but you did specify "our current understanding of physics.")
As to size, on galactic scales all our current fusion designs are tiny. Scale it up to even just 20 miles on a side and proton proton fusion is doable. For a type III civilization capable of destroying starts that's also tiny. Remember your suggesting dysons spheres as the 'reasonable' option.
Why should an advanced civilization necessarily create the artifact mentioned in the article. The conclusion because we don't see this artifact, so type III societies don't exists seems too strong. Maybe they don't create giant veils around galaxies and instead have virtualized themselves, or can simply convert matter to energy at will. What use would there be in wrapping a giant ball of dust around a galaxy when you can convert matter directly to some other energy/form?
Probably I think "they" are formless and more information based than physical. We aren't even sure if this reality is real or a simulation anyway, so why limit our thinking to advanced civilizations in the world as we know it?
> Whether technological societies remain small and planet-bound like our own, or ultimately span across galaxies is an open question in the Search for Extraterrestrial Intelligence.
Harnessing stellar output might not be that interesting. Power density inside stars kind of sucks (about that of a reptile) and stars have bad failure modes.
You're probably better off disassembling the suckers and storing their matter in a sensible way, rather than have it sit there, burning. Stars are kind of like trash fires; maybe we should be looking for less energy in a type III civ, not shielding.
Just to play devil's advocate -- density isn't everything either.
Plants on Earth play an incredible optimization game. Water is necessary not just for chemical metabolism, but because throwing it away is an essential part of the internal material transport systems of a plant. Evaporation in the leaves creates a relatively lower osmotic pressure in the higher levels of the plant. Between capillary action and the slight but insistent pull to replace evaporated water in the leaves, plants have a pumping mechanism with essentially nil energy input: minerals and nutrients gathered in the roots just ride on up with the tide.
Stars may be a similar story for efficient fusion. Sure, with sufficiently advanced technology, I can make inordinately denser energy sources with less boil-off. But do I want to? Maybe letting the brute physics of a gravity well do the job simply has unbeatable efficiency -- just like evaporation as one end of a pump for plants on Earth is clearly no comparison to any motorized pump for volume, but for cost-effect, nothing else comes close.
>>just like evaporation as one end of a pump for plants on Earth is clearly no comparison to any motorized pump for volume
But what if we need/want volumes? The way we can't (or don't want to) use trees/plants for pumping water in time-efficient manner, we may not (want to) use the gravity brute force based stars as energy sources and we may invent more time-efficient fusion reactors.
A Type III civ is probably going to take the long view. The really long view. And in the long run, efficiency is everything.
Stars are just so wasteful; all that energy going into convection currents, and you have to build this big damned sphere to capture all the energy. Better to lift the damned thing and, at the very least, make a dwarf star out of the larger ones. Now you're talking trillions of years of burning (it's still a trash fire, but at least it's manageable).
If I had super cool tech, I'd use Hawking radiation from small black holes as my means of turning matter into usable energy. Much more compact than a star, and the energy density is also a lot better.
He estimates f_l, the probability of life arising in a habitable planet, as 0.1.
Abiogenesis has never been observed to occur independently of its presumed occurrence when life started on Earth.
Given the current state of scientific knowledge on this topic, the only certain lower bound on this number is the probability of molecules in a suitable "organic soup" arranging themselves into a self-contained bacterium. And that probability is a _very_ small number.
If f_l is _very_ small, then there is no need to be pessimistic about our own long-term survival. We see no advanced alien civilisations, because there is no other life out there of any kind - the rest of the observable universe is sterile.
Even if abiogenesis is common, the transition from simple to complex cells is incredibly uncommon. As far as we can tell it only happened on earth once in 4 billion years.
f_l may be 0.1 but f_i is almost certainly multiple orders of magnitude smaller.
If we expect to see the "brightness of the blackbox caused by the radiation of a Type III Kardashev Civilization", and we inspect galaxies that are maybe millions of light-years away from us, would we not be looking at how did those galaxies look millions of years ago?
That is, maybe there are Type III Kardashev Civilizations and their usage of the energy of their galaxy in fact radiates energy that would be visible to us... except that they've evolved to that point much later that the light we're receiving since it takes millions of years for that light to reach us.
In those millions of years they could very well have reached that technological level, but it will take some more millions of years for that to reach us... by that time mabye that Civilization doesn't exist anymore... Maybe our civilization doesn't exist anymore...
In this case we extract information from the radiation that comes from those galaxies, and the information is too slow to travel such vast distances, since it can't go faster than the speed of light.
In summary, we're looking for ANCIENT Type III civilizations.
> In summary, we're looking for ANCIENT Type III civilizations.
Yes. This is because of the low probability that intelligent life develops somewhere else at even close to the same time as it did on Earth.
Our best understanding is that life has existed on Earth for something like 4 billion years, and complex life has existed for about 500 million. However, complex life capable of building spacecraft (or even radios) has only existed for a few hundred thousand (that is being extremely generous, of course), and only developed that technology in the last ~100 years.
If intelligent life has or will evolve somewhere else in the universe, and progresses anything like it did here, then the odds seem overwhelmingly in favour of one of two scenarios:
- It evolved millions of years ago, and if it has not wiped itself out, is virtually god-like by our standards due to its head start on technological development.
- It has not yet evolved, or at best is the equivalent of primates or the proto-humans of several hundred thousand years ago.
well.. if we don't get off this planet within the next (approx) 4 Billion years.. our species will snuff it as the sun grows to a red giant.
so assuming all life across the universe starts from similar beginnings as us, then this tells us something about what an advanced civilisation needs to be capable of to survive.
Speculation like this is fun, but I think it's little more than intellectual masturbation until we crack fusion energy. Until we understand the energy economy with such technology, and the most efficient way to leverage it, we're not going to understand the most significant factors that we should be considering. And even then, we'll only be starting to get the slightest clue of how Type II and III civilisations might work.
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[ 3.3 ms ] story [ 155 ms ] threadhttps://www.youtube.com/watch?v=XhkwT466ykc
[1] https://en.wikipedia.org/wiki/Dyson_sphere
... and now we have a sci-fi reason for quasars. :)
I question how stealthy that would really make you, though. If someone was bothering to look for stealthy civilizations, they'd just have to scatter some observatories around their region of the galaxy, then watch. Eventually, your structure would occult a star from the POV of one of those observatories, or they'd pick up your beam scattering in interstellar gasses or dust clouds.
I realize this is all space opera, not hard SF. It's still fun.
"There's nothing here, Captain. Nothing at all. So you're saying that they moved an entire star system? In the last solar cycle?"
Good times, good times.
[1] https://news.ycombinator.com/item?id=11588918
It's more likely that beyond a certain point you have all the energy you can use, and the limiting factor becomes collective intelligence.
I'd guess that in the same way that processors keep getting more efficient, so do civilisations. At the highest levels the energy signature of a civilisation is virtually indistinguishable from the cosmic microwave background - if it's observable at all.
Why is this more likely?
It might not be 100% secure but it's not meant to be, either. Just more secure than nothing.
1. Advanced societies have probably solved the aging problem, leading to either extremely long lives or effective immortality. As long as these societies keep reproducing (and they will, unless they deliberately engineer out the urge to procreate, which I consider to be unlikely), they'll need space to spread out. Sure, they could probably pack themselves like sardines into a single solar system, but that only works if they'll be spending 100% of their time in virtual reality, and that would be begging the question.
2. A need for resources. Type III societies can capture 100% of the output of a star, but even this amount of energy might not suffice once society grows large enough. And even at that level it's still probably easier to manipulate matter than it is to convert energy into matter, so it'll be more efficient to harvest planets and asteroids and whatnot for raw building materials, which means leaving the solar system.
3. Even assuming they manage to create virtual reality that is 100% indistinguishable from reality, it's likely that there will still be a lot of beings that will reject the idea of living 100% in virtual reality simply because it's virtual. Even if it's indistinguishable from reality, they'll still know it's not real. So they may visit VR, but will want to actually live in the real world. Or in other words, humans have shown a tendency towards the perverse, and it's not unreasonable to assume aliens will too.
4. Any kind of scientific research still being done at that level will likely require the use of reality instead of VR. VR is a simulation, and even if it's indistinguishable from reality to your senses, it's still presumably not actually simulating reality down to the planck level (because it's part of the universe, it cannot simulate the entire universe at the same fidelity that the universe itself operates at, as that would presumably require more information than the universe contains), and so there's probably a fair amount of research at that level that simply can't work in simulation and requires testing against actual reality.
If they had as little agency around the issue of population control as you suggest, this makes me question their status as "advanced."
Beyond that, if you have effectively infinite space and resources, there's no need at all to have even the slightest bit of population control. Population control is only necessary to ensure adequate resources (including space to live) for everybody. But when there's no constraint on resources, there's no reason why anybody shouldn't have as many children as they desire.
So you suggested that their civilization as a whole had little agency around population control.
Beyond that, if you have effectively infinite space and resources, there's no need at all to have even the slightest bit of population control.
You're forgetting simple geometry. Space empires can only expand proportional to n^3, while their population could potentially expand proportional to k^n. Also, in a situation where there are multiple star-faring "species," a hegemonic, exponentially expanding entity might well be viewed by others as worse than obnoxious.
Given these reasonable assumptions, it seems likely to me that most space-faring civilizations of this level of technology will never experience any kind of pressure on living space. If you've ever read the Culture series (by Iain M. Banks) then you might reasonably expect such a civilization to "Sublime" before running out of space. Or to eventually alter themselves so as to remove the desire to procreate in a deliberate move to "retire" from the galactic stage.
I said "most" because there is of course the possibility that some species comes along that has the urge not just to procreate but to have as many children as possible as fast as possible, and manages to achieve this level of technology without ever altering this behavior. Such a species that is driven to expand its population as fast as possible may then experience restrictions on living space, but such a species would eventually have to enact population control, which could take the form of altering themselves to remove this urge to procreate as fast as possible and therefore will become just like "most space-faring civilizations".
From the POV of an outsider or a different species, would any entity care about the difference between "effectively/pretty much" and what you deem to be "actual" population control?
I doubt it.
So basically, you haven't been disagreeing with me, just splitting hairs on what the words "population control" means. I'm using a more generic criteria: Is the population controlled?
As I understand it, the argument is basically that, assuming true high-fidelity virtual reality is possible, then it's likely that any society that advances far enough technologically will eventually create a virtual world and populate it (or let it populate itself) with virtual beings that don't know they're in a virtual reality. Given this assumption, if you let the virtual reality run long enough, then the virtual beings inside the virtual reality will eventually end up creating yet another layer of virtual reality. Assuming this is possible at all, it then follows that there could be an effectively infinite number of virtual realities layered inside each other, and under those circumstances, it's extremely unlikely that our reality happens to be the outermost "real" reality but is instead somewhere in the stack of virtual realities.
If the universe is all the same age and if the emergence and evolution of life is tied to the overall thermodynamic evolution of the universe, then everything might be approximately of the same scale and complexity within a certain standard deviation.
If this is true then when we go out there we will meet all the others who have also just developed to that level.
Of course since we have basically no data, we can't actually argue either way beyond vague hand-wavey speculation. You can't calculate standard deviation from a sample size of one.
That such a synchronization mechanism should work with such precision over the entire universe seems very unlikely. Filtering would not require synchronization, so that seems much more likely.
Here's the speculation in more detail:
Evolution can be viewed as an information transfer mechanism that learns about the universe and transfers that information into the genome. (This is one interpretation found in evolutionary information theory.) As the universe inflates there is more total information in it, and therefore more information for evolution to learn. At certain points, a kind of information density "critical mass" is reached and phase transitions occur: the emergence of life, complex life, cooperative/multicellular life, higher order intelligence, industrialization and complex society, etc. Since the total amount of information in the universe is (we're speculating) tied directly to the arrow of time, this occurs simultaneously everywhere at approximately the same time.
Again this is hypothesis bordering on speculation since we do not know of any mechanism that directly couples information content to cosmic inflation like this, or even how we would go about measuring such a thing objectively. For instance it's not possible to differentiate between random and encrypted data using Shannon information measures, so what statistic would you use?
Furthermore, if it has such a powerful and pervasive effect on evolution, why haven't we already discovered it in our studies of evolution to date? We live on a planet chock full of evolving life.
We are separated from mice (or at least somewhat similar animals) by approximately 40m years of evolution, I think that the separation to a Galaxy altering level entity would be much more profound, and frankly we wouldn't understand what it was if it came and tickled us.
We are separated from mice by 80million years of evolution -- 40million from the common ancestor, and 40million to the other modern species.
Or simply 40million years of divergent evolution.
I did get the date wrong - I should have said 65my.
Here is a link
http://www.smithsonianmag.com/science-nature/five-early-prim...
For an example, I point to the horseshoe crab. We're separated by x million years of evolution from the horseshoe crab, because at some point there's a common ancestor. Its ancestor evolved to the horseshoe crab, millions of years ago, and then stopped. Meanwhile, our ancestor continued to evolve into us. The horseshoe crab is a prehistoric animal, a "living fossil". It hasn't evolved significantly in millions of years. This is quite different from mice.
Another example is the coelacanth fish; it was thought to be long-extinct as we have prehistoric fossils of it dating to the dinosaur days. Turns out it's still alive. Another less-extreme example is the shark: it's a little different than its prehistoric ancestors, but not much. I'm sure a biologist could point to a bunch of other species that haven't changed significantly since the days of the dinosaurs.
Mammals like mice have indeed been evolving just as long as we have, but many non-mammalian species have not.
If we take mind upload as a given, then it should also be possible to create "clones" of our minds with ease. This level of technology will have a profound effect on the value society places on individuality.
"all" is usually the key issue with solutions to the Fermi paradox. We can certainly find reasons for any given civilization to go the other way, but it's more difficult to argue that all of them do.
I would also argue that life itself has proven remarkably long-term stable on our planet. Granted, it has not been stable enough to produce a type-III society, but if we remove homo sapiens from the planet for a thought experiment, there exist other species that are developing communication or tool-use skills and might succeed us even on the technological path.
So my view is that, unless we continue to fail spectacularly, life will still continue without us. Even if we do not reach type-III, that does not necessarily preclude Earth from producing a type-III society in the future.
Sounds like you are the one who has a narrow view of "society," rather. In the abstract, it only need be something like "a multitude of cooperating but competing, independent self-preserving, self-advocating sentient interests." That's fairly abstract while still being a sure recipe for highly non-linear and chaotic effects.
Even if we do not reach type-III, that does not necessarily preclude Earth from producing a type-III society in the future.
But then you're setting up a situation where a series of chaotic and unstable arrangements snuff themselves out or flare-out in a puff of singularity-colored smoke, ending with the appearance of the first stable meta-societal form.
At least if society is doomed we'll only doom ourselves, and not the entire Milky Way! One takes what cheer one can get when pondering this sort of subject.
Tons of unknown variables filled-in with vigorous hand waving, ad-hoc and unproven assumptions left and right, etc, and some high school math thrown in for good measure...
Seems to me like a completely rationale thing to measure about the universe. Imagine if the result had come back true?
Ah, I see. It's a play on words. "Apparently" is meant as "is visible", not in the sense of "this is true". Astronomer humor.
But I get what you mean.
There are huge number of assumptions based on that idea. A fundamental one is that a civilization in a relativistic universe would grow to densely inhabit a galaxy. Another is that they would need that much energy. Another is that even if they did have need for that much energy, they'd bother collecting EM radiation from stars.
That third is an interesting one to me. Now, you could muck up the night sky for the entire Milky Way, or you could, with Sufficiently Advanced Technology (tm), annihilate a total of 10 Jupiter-masses a year across the whole galaxy. For your average star system, that's extracting energy from 1.1 billion kg of mass a year, or roughly what NYC's garbage collection services dispose of every two weeks.
Pondering that, I suspect it's the wrong idea to imagine that a very advanced civilization, something we can only understand in the dimmest sense, would be constrained by something as specific as stellar energy emissions.
Even if they needed that much energy, the best way to do that [that we know of] is to build a Dyson sphere. With every star shrouded by a Dyson sphere you no longer need to shroud the galaxy.
A more critical assumption is that a type III civilization even cares about masking its presence. If they were even worried about being attacked, the speed of light would mask their progress for a great deal of time and, because of the distances involved, even seeing them once the light reaches you would be a massive accomplishment - most likely you'd have to search for individual stars in another galaxy which are disappearing in unusual ways.
A type II civilization could possibly build a telescope with a large enough aperture but I assume that type II civilizations would be long past their ignorant warring ways.
Also, a civilization could have dimantled Andromida Galaxy 2 million years ago and can't tell yet. For more distant objects the gap gets rather wide.
It's entirely possible to burn deuterium in small reactors but there's only about 1/2500 as much deuterium as hydrogen.
(Perhaps some unthinkably advanced civilization could figure out how to get energy from hydrogen fusion in a small reactor, but you did specify "our current understanding of physics.")
As to size, on galactic scales all our current fusion designs are tiny. Scale it up to even just 20 miles on a side and proton proton fusion is doable. For a type III civilization capable of destroying starts that's also tiny. Remember your suggesting dysons spheres as the 'reasonable' option.
PS: The proton proton chain also produces deuterium as an intermediary. https://en.wikipedia.org/wiki/Proton%E2%80%93proton_chain_re...
In order to qualify as a Type III civilization, you pretty much need to harvest ALL of the energy in a galaxy.
What questions in this field are not open?
You're probably better off disassembling the suckers and storing their matter in a sensible way, rather than have it sit there, burning. Stars are kind of like trash fires; maybe we should be looking for less energy in a type III civ, not shielding.
Plants on Earth play an incredible optimization game. Water is necessary not just for chemical metabolism, but because throwing it away is an essential part of the internal material transport systems of a plant. Evaporation in the leaves creates a relatively lower osmotic pressure in the higher levels of the plant. Between capillary action and the slight but insistent pull to replace evaporated water in the leaves, plants have a pumping mechanism with essentially nil energy input: minerals and nutrients gathered in the roots just ride on up with the tide.
Stars may be a similar story for efficient fusion. Sure, with sufficiently advanced technology, I can make inordinately denser energy sources with less boil-off. But do I want to? Maybe letting the brute physics of a gravity well do the job simply has unbeatable efficiency -- just like evaporation as one end of a pump for plants on Earth is clearly no comparison to any motorized pump for volume, but for cost-effect, nothing else comes close.
But what if we need/want volumes? The way we can't (or don't want to) use trees/plants for pumping water in time-efficient manner, we may not (want to) use the gravity brute force based stars as energy sources and we may invent more time-efficient fusion reactors.
Stars are just so wasteful; all that energy going into convection currents, and you have to build this big damned sphere to capture all the energy. Better to lift the damned thing and, at the very least, make a dwarf star out of the larger ones. Now you're talking trillions of years of burning (it's still a trash fire, but at least it's manageable).
Abiogenesis has never been observed to occur independently of its presumed occurrence when life started on Earth.
Given the current state of scientific knowledge on this topic, the only certain lower bound on this number is the probability of molecules in a suitable "organic soup" arranging themselves into a self-contained bacterium. And that probability is a _very_ small number.
If f_l is _very_ small, then there is no need to be pessimistic about our own long-term survival. We see no advanced alien civilisations, because there is no other life out there of any kind - the rest of the observable universe is sterile.
f_l may be 0.1 but f_i is almost certainly multiple orders of magnitude smaller.
That is, maybe there are Type III Kardashev Civilizations and their usage of the energy of their galaxy in fact radiates energy that would be visible to us... except that they've evolved to that point much later that the light we're receiving since it takes millions of years for that light to reach us.
In those millions of years they could very well have reached that technological level, but it will take some more millions of years for that to reach us... by that time mabye that Civilization doesn't exist anymore... Maybe our civilization doesn't exist anymore...
In this case we extract information from the radiation that comes from those galaxies, and the information is too slow to travel such vast distances, since it can't go faster than the speed of light.
In summary, we're looking for ANCIENT Type III civilizations.
Yes. This is because of the low probability that intelligent life develops somewhere else at even close to the same time as it did on Earth.
Our best understanding is that life has existed on Earth for something like 4 billion years, and complex life has existed for about 500 million. However, complex life capable of building spacecraft (or even radios) has only existed for a few hundred thousand (that is being extremely generous, of course), and only developed that technology in the last ~100 years.
If intelligent life has or will evolve somewhere else in the universe, and progresses anything like it did here, then the odds seem overwhelmingly in favour of one of two scenarios:
- It evolved millions of years ago, and if it has not wiped itself out, is virtually god-like by our standards due to its head start on technological development.
- It has not yet evolved, or at best is the equivalent of primates or the proto-humans of several hundred thousand years ago.
so assuming all life across the universe starts from similar beginnings as us, then this tells us something about what an advanced civilisation needs to be capable of to survive.