Most people get baked, wonder if we're alone in the universe, and take a nap. Astrophysicists get baked, wonder if we're alone in the universe, and publish papers like this.
Jokes aside, is there really any practical value in this sort of research, or is it the kind of thing that we do because it's interesting and kinda cool? Don't get me wrong, I think it's valuable for that alone, but...
> is there really any practical value in this sort of research
In many ways it is too early to do this research, so it is a kind of art (as is a lot of research, imho). As long as only a few people do it, it's cool and useful so we can be aware of our potential future.
On the other hand, since we have no credible evidence of extraterrestrials, it would be surprising to find a civilisation so advanced to build a Dyson sphere. If they can build Dyson spheres, wouldn't they already be all over the place?
Ok, I suppose I should actually go read the paper now...
Being able to build Dyson spheres does not make them capable of going faster than the speed of light, so any civilization capable of building a Dyson sphere would probably still be clustered around a couple stars and that's it.
Would such a civilization spread to more than one star is actually also a question, or would they control their population rationally stay on their Dyson sphere and only start to move when the star had less than 100,000 years left to go.
Only some Dyson sphere variants, like Shkadov thrusters, are primarily conceived as ways to move around. Which personally seems to me less likely, is a civilization, as well as the ability to construct these objects, also going to have a species level interest in going exploring?
> "Being able to build Dyson spheres does not make them capable of going faster than the speed of light, so any civilization capable of building a Dyson sphere would probably still be clustered around a couple stars and that's it."
Check your math: this galaxy is ~10^5 light-years in size and ~10^10 years in age.
what does that have to do with anything I said? Yes, I guess they would be everywhere if their civilization was able to make Dyson spheres 1 year after the creation of the galaxy, also if they decided to
1. Not control their population for some reason.
2. Had some sort of interest in exploring.
3. Implicit also in the speed of light thing, would find it really interesting to send a portion of their population to the next available and suitable star which might be enough light years away to make communication impractical. I mean for our civilization there is some level of argument that says it would be a ridiculous idea to move to a new solar system and we have an intellectual exploratory streak in our species.
I mean we are currently not at the level of being able to do a Dyson sphere, it took us 4.543 billion years (age of earth) to get to the part that somebody could conceive of it. There is also some discussion as to whether or not our civilization is going to last, so given that and the other things I said it seems unlikely to me that any Dyson sphere civilization would actually build more than one, but maybe some build two because binary stars or some other weird circumstance which makes it worthwhile to do.
on edit: if we get to Dyson sphere building capabilities which seems really unlikely, will we build more than one? How many more?
The point is that you don't need to go faster than the speed of light. There's more than enough time to cover the entire galaxy in a relatively short period of time at sublight speeds. A few million years is sufficient.
yeah, sure, enough time to GO everywhere but not enough time to BE everywhere, which is a different thing entirely, even if all the other things I brought up as to why the aliens weren't everywhere were not things to take into consideration.
So again, still haven't heard any argument why an alien civilization achieving the ability to build Dyson spheres, even if they did so far enough in the past that they would then have adequate time to traverse the galaxy afterwards, would then have to be everywhere?
I'm not sure I understand your argument. There is sufficient time, with waves of colonisation to spread across the galaxy many times over. This can include pauses of thousands of years between colonisation waves. Some of those colonies could also build Dyson spheres. You would end up with them scattered all over the galaxy. Even if the colonies dies out subsequently, the spheres would still be detectable.
>I'm not sure I understand your argument. There is sufficient time, with waves of colonisation to spread across the galaxy many times over.
yes, there is, if the achievement of Dyson sphere building happened long enough in the past for there to have been sufficient time. 50,000 years ago even, no. The length of human civilization is 6000 years approximately, what if this civilization much, much older than ours 6000 years ago just started building it's first Dyson sphere. For some reason the assumption is that it was far enough in the past that they COULD be everywhere if they wanted to.
But then the phrasing is not that they could be everywhere but rather they would be everywhere, hence no civilization has built Dyson spheres. A lot of this theory that the aliens will go about building lots and lots of Dyson spheres seems based on the assumption that they will be a lot like us, but actually I don't even think we would ever build more than one. If we built a Dyson sphere it would be because we were at the point we needed the energy and we had the technology to do it of course, and we had a political system that could harness everyone to do it. But once we had the Dyson sphere I am not sure we would ever be at the position were we would need another one. Since people tend to have fewer kids the higher their standard of living it may be that with the standard of living of Dyson sphere civ that our population would be at replacement level, that is to say we would never need to move from one Dyson sphere until the sun was just about used up.
So again, sure there is sufficient time with waves of colonization (started far enough in the past) - but waves of colonization assumes a species that has a colonization urge and perhaps one that has a colonization urge greater than that of humanity. That's a pretty big if, considering all the other big ifs in the whole building a Dyson sphere scenario.
I'm not sure anyone is arguing that aliens who can build Dyson spheres HAVE to be everywhere. They could, as you say, just build one or two and live there. Or a species that colonises could build them as it goes.
They may not be moving around to explore so much as to keep their solar system safe.
Galactic orbits are far more chaotic than the sedate stable orbits within the solar system - stars closely approach each other on a somewhat regular basis.
No Dyson spheres, but there are black holes all over the place. Some people think those would make great computing devices, many of their origins are not well explained as super nova remnants, and they efficiently harness energy from companion stars. They have all the properties of Dyson spheres but they actually exist. Maybe with advanced enough physics, intelligent civilizations learn to manufacture and harness black holes, neutron stars, and other dense objects for societal benefit.
This is the first time I've heard of this. Wow, yes! A blackhole is far more efficient at consuming energy than a Dyson Sphere... the hard part though is kickstarting the process I guess
> No Dyson spheres, but there are black holes all over the place. Some people think those would make great computing devices
They’re crappy computing devices. Even if you figured out how to program one — and that’s an “if” that would make Sagittarius A* look like a neutrino — there’s no way to read the information out except Hawking Radiation, and that would take 10^70 years.
> If they can build Dyson spheres, wouldn't they already be all over the place?
I figure they'd have to be.
They'd need more than a solar system's worth of raw resources to build the sphere. They may need more than a solar system's worth of resources just to build the tools and craft to be able to build the sphere. They're going to need an insane amount of production facilities for various components, and that's going to take a massive amount of resources. That's going to require exploring quite a bit of a galaxy.
> they calculated that any galactic empire would have spread outwards from its home planet at about 0.25% of the speed of light. The result is that after 50m years it would extend over 130,000 light years, with zealous colonisers moving in a relatively uniform cloud and more reticent ones protruding from a central blob. Since the Milky Way is estimated to be 100,000-120,000 light years across, outposts would be sprinkled throughout the galaxy, even if the home planet were, like Earth, located on the periphery.
It’s actually so fast that advanced civilizations would have had time to colonize the galaxy and go extinct many times over without us noticing.
Or maybe their spheres were built so long ago they’ve already collapsed and been consumed by the stars again.
It’s a great mystery and interesting thought experiment though.
Our ancestors from 50M years ago are all extinct. So a civilisation spreading through the galaxy would have evolved in all kinds of different ways. It's not obvious to me that these diverse evolutionary strands would all still be interested in Dyson spheres, or space travel, or even astronomy.
There's a belief that's hard to shake off, that the properties humans have that we think most important represent some kind of evolutionary pinnacle. Typically, those properties are language, and a large brain for processing language. But if language and a large brain are really such great evolutionary advantages, why are humans the only creatures on Earth that have evolved those properties? Possibly language and a large brain are an evolutionary backwater.
At 0.25% of the speed of light, it would take us 1,600 years to reach Proxima Centauri; but it might take a lot longer to reach a star with habitable planets. We'd definitely need generation ships. After (say) a million years, we'd presumably have evolved to adapt to life on generation ships. It's not obvious to me that such adaptations would leave us fit to inhabit a planet. And perhaps adaptation to life on a generation ship means adapting to eating your fellow passengers.
Given the history of humanity, I find it hard to believe that the population of a generation ship could survive as long as 100 years without war breaking out on-board. We've had large brains and language for about 50,000 years, as far as I can tell; we've been warring the whole time. Maybe large brains and language pre-dispose us to war? If that's right, then it seems unlikely that intelligent life would ever spread far from it's planet of origin.
I'm very sceptical of the idea that any "civilisation" could ever spread far from its home planet. There are two things that we refeer to as a civilisation: a culture, and a species. Culture changes very quickly - over a single lifetime. But on a scale of millions of years, speciation is also pretty quick. So I can't see how any kind of homogenous civilisation or species could spread through a galaxy. They would have diversified before the train even reached its first stop.
So I don't have any insurance against being kidnapped by aliens.
Indeed, any culture that actually lasted long enough to get to the next star would have become, in the interval, comfortable with not being near any star, and could roam freely, doing nothing that could attract our attention.
True, unless their lifespans are high enough that a trip to a nearby star is only a fraction of their existence (or they travel cryogenically and aren’t conscious during transit).
> why are humans the only creatures on Earth that have evolved those properties? Possibly language and a large brain are an evolutionary backwater.
Nearly every animal has language, for cooperation, competition, raising their young or to find a mate. Bees, whales, primates, birds, etc. all communicate strategically with some type of language.
> Given the history of humanity, I find it hard to believe that the population of a generation ship could survive as long as 100 years without war breaking out on-board. We've had large brains and language for about 50,000 years, as far as I can tell; we've been warring the whole time.
It’s possible to find many countries who have not fought wars in the past 100 years. If you look more narrowly it’s possible to find communities unaffected by local war in hundreds or maybe even thousands of years (in other words, they fought a war but did so by traveling great distances, not fighting each other).
A ship would be much more like a tiny, isolated island colony rather than the geopolitical tensions that dominate the news.
Finally, wars rarely result in the extinction of both sides. Even if there was a large scale conflict it would likely be resolved prior to social collapse. There would be little incentive to kill so many of your fellow crew to the point where you’re putting every survivor at risk.
>> why are humans the only creatures on Earth that have evolved those properties? Possibly language and a large brain are an evolutionary backwater.
> Nearly every animal has language, for cooperation, competition, raising their young or to find a mate. Bees, whales, primates, birds, etc. all communicate strategically with some type of language.
There is currently only one species on Earth capable of even imagining the things being discussed here. On the other hand, it seems there may well have been more, but the others are now extinct.
One of these issues only we are discussing is the evolutionary viability of those abilities, and the fact we can do so suggests that it is, to some extent, up to us whether or not they will be.
Yes, I elided that bit, in the aim of brevity. I think there is a difference between human language and animal languages, in that human language is "creative" - we can freely create new utterances with new meanings, and expect to be understood. We know this of human language, but I would be very interested to learn of evidence of it in other species (chimps come close).
It's just struck me that a civilisation propagating through space can be envisaged a bit like light-cones, as in GR, except that the velocity factor isn't c, it's b (the maximum speed at which beings can move), which kinda depends on the beings.
But I think the cones thing is still interesting; it means that for any given maximum travel speed, there must be other civilisations that can never know anything about you, nor you about them.
> Our ancestors from 50M years ago are all extinct. So a civilisation spreading through the galaxy would have evolved in all kinds of different ways. It's not obvious to me that these diverse evolutionary strands would all still be interested in Dyson spheres, or space travel, or even astronomy.
There is no need for all, or even most, of the civilizational variants to retain those characteristics. As long as some variants do, civilization would continue its inexorable interstellar spread, it would just end up being lumpy rather than a relatively even wavefront.
Indeed, survivorship bias would seemingly tend to conserve the required characteristics and possibly start constraining the ways in which civilizational offshoots can vary. And it isn't hard to imagine stay-at-home variants succumbing to the influence of later arriving spreader variants to become spreaders once more.
It depends on how you define practical value. Immediately capitalizable? Probably not outside of Hollywood. Building a theoretical underpinning for the future of our species? I hope so.
Research is ALWAYS limited to what the person performing it considered practical. Getting a paper published is as practical as most researchers need to get. (Some do more.) If they don't publish, they soon don't get to do research anymore, and have to start doing what somebody else considers practical.
You missed the word I wrote "should". Funding agencies want to fund only "practical" research. But studying the migratory patterns of a single species of butterfly should be funded as much as the latest biotech fad that supposedly is of "practical value".
Searching for Dyson spheres is not too different from searching for other hypothetical astronomical objects. Maybe it is a low-stakes analysis you could put some students on, so they learn something. Data collection, statistical methods, paper writing is all identical to "traditional" searches. I come from particle physics, and we did quite a few searches for very weird particles that, I admit, didn't believe in. But it was quick to retool the search for more plausible models.
Also I think science works the way that you use your fantasy to come up with outlandish things, and then try to rule them out with logic.
Dyson sphere would emit significant amount of infrared light but no visible light. Original Freeman Dyson's paper from 1960 was titled "Search for Artificial Stellar Sources of Infrared Radiation" https://sci-hub.ee/10.1126/science.131.3414.1667
Was there any practical value in Columbus discovering America? If the Aztecs had instead sailed to Europe or Africa and discovered them, would that have been of any practical value to them?
It's difficult to imagine a discovery that would have more practical import than the discovery of an extraterrestrial civilization.
I believe the person you are replying to is saying “discover” relatively rather than Euro-centrically, as they mention a hypothetical Aztecs “discovering” Europe and Africa.
A discovery doesn't have to imply that no living being knew about said thing/ place. It can imply only that the person or the group of people the person is from learns about this new thing. At some point in time nobody in Europe had definite proof of how to get to America. You can call "europeans learning how to get to America" something else other than "discovered America", but what phrasing should one use instead?
To make the point, literally nothing can be classified as "discovered" under your rules because any alien civilization may know about everything we'll ever find or figure out, and if they know about it we can't have discovered it.
Columbus was a murderer and people in America before he got there deserved way better but this type of nitpicking correction is just noise if you don't even say what is a more appropriate phrase.
Are you saying that, even if extraterrestrial civilizations existed, looking for Dyson spheres wouldn't reveal them? Or are you saying that they don't exist, so nothing will reveal them? In either case, why?
Looking for Dyson spheres wouldn't reveal them, because any extraterrestrial civilization sophisticated enough to make one wouldn't need it or want it.
> Was there any practical value in Columbus discovering America?
Why, yes, of course - even in the immediate short term the ships returned from expeditions with gold and slaves; and from the very start the exploration voyages were planned and funded solely as a practical endeavor for trade and looting, not as an intellectual curiosity.
It's a low cost, low probability way to look for advanced civilizations. Chances are low that you'll find anything, but hey the data's already here and we have powerful computers so let's run some calculations. And occasionally you find weird and interesting anomalies that push science forward: https://www.space.com/alien-megastructure-mysteriously-dimmi...
Dyson spheres are just inane.... sorry but they don't make sense.
Any advanced form of civilization that can build one, probably figured how to do fusion efficiently locally and doesn't have to build these insanely inefficient energy harversters.
Keep in mind that the sun is very inefficient at energy release.
Dyson sphere prediction is like predictions in the 1800s how we would have coal and steam powered airships to travel around.
The reality is that steam via coal fire is too inefficient. Coal is just too heavy. Jet fuel is much more efficient/energy dense and not need to build giant airships.
Same with any advanced civilization. Dyson spheres just don't make sense, but they sure make good sci-fi movies/stories for the gullible.
The ingredients for fusion reactors (deuterium, tritium and helium-3) are rare, not fully reacted intermediate byproducts of the proton-proton cycle that powers the sun.
The likeliest case for a Dyson Sphere civilization would be some sort of solar powered Gray Goo von Neumann replicator.
The ingredients for the most primitive, low-tech, hayseed fusion reactors are sort of rare. But anybody with any sophistication at all has no need for such primitive processes. They fuse plentiful regular hydrogen, helium, and, not to be wasteful, whatever they get from fusing those, too.
"do fusion efficiently locally" - with what? The vast majority of available fuel is in the stars.
Dyson spheres are different than planet size civilization. For planet size civilization, with population in the order of billions/trillions ppl, local fusion is probably good enough. But for populations a billion times bigger, so billions of billions of ppl, you need dyson spheres, or alternatively, a way to destroy stars and get the raw hydrogen - probably harder to do.
Hint: Jupiter is made mostly out of hydrogen. Saturn too. Uranus and Neptune, if those get used up. Also plenty of helium, maybe even more useful.
Also: the Pacific, Atlantic, Indian, and Arctic oceans are made of water, which has hydrogen in it. Also all of the Antarctic and Greenland ice, the Great Lakes, Caspian Sea, Lake Baikal, and Lake Victoria.
Why wouldn't they do fusion locally but also build a Dyson sphere? Doing only the former produces less energy than doing both the former and the latter.
The view that they wouldn't do both is premised on the assumption that they won't need or want that much energy, combined with the assumption that the problem of disposing of the waste heat makes the extra energy not worthwhile.
The word "need" is misplaced. It's not about need. It's about whether the upside of the additional energy is bigger than the downside of having to build the thing out. You're making an assumption that that upside is too small relative to that downside.
You assume that energy would still be considered a limiting resource. When you have overabundant energy, your choices are driven by other concerns. With plentiful energy, materials are cheap, dismantling moons and minor planets. The actually valuable commodity becomes cold, because high-energy processes produce waste heat that must be radiated away, so you move out to the Kuiper belt.
If you were using that much energy you would have the much bigger problem of disposing of all the waste heat afterward. You could not do that close to a star.
Not necessarily as some stars are wasteful (use energy to fuse bigger atoms) or have material in the core it can't fuse. If you are just concerned with energy output per mass you can do better artificially in theory
It's worth noting "Dyson Sphere" is a product of sci-fi literature. Freeman Dyson himself only described an "artificial biosphere" in some paper he published, sci-fi authors mistook him literally (or were just being creative). He wasn't even describing anything resembling a physical sphere surrounding a star.
He speaks to the subject in this excellent interview playlist, link is to the specific Dyson Sphere part:
Presumably if your super-advanced civilization needed more energy than could be fused from all the matter in a planet, you would have to get it from a star.
Presumably if you are a super-advanced civilation, you would get power from what would appear to us mere primates as essentially thin air, in a fashion we can't even fathom.
"Any sufficiently advanced technology is indistinguishable from magic."
I'm right here with you, love the haters too that downvote you. The real takeaway is simply this: we don't (and can't) KNOW what type of energy advanced civilizations will have (and we might not even be able to understand it if we saw it!), and collective scientific time is much better spent on things that we DO know, like searching for bio markers similar to earth.
I'm not clear what is meant by "inefficient at energy release". Does that mean that the in the process of energy release, some of the energy is converted into heat? I.e., more energy?
I once got the chance to ask freeman dyson what he recommended educationally, for children, to produce more freeman dysons.
He didn’t hesitate. He said we need to teach children genetic engineering to children in such a way that they could approach it playfully. Only then would we have a chance of developing warm blooded plants which would be essential for colonizing the asteroid belt.
"The first species to emerge from a Noah’s Ark egg will be warm-blooded plants designed to collect energy from sunlight and keep themselves warm in a cold environment. “Plants could be engineered to grow greenhouses the way turtles grow shells” The greenhouse would consist of a thick skin providing thermal insulation, with small windows to admit sunlight. Outside the skin would be an array of simple lenses, focusing sunlight through the windows into the interior. Groups of greenhouses could grow together to form extended habitats for other species of plants and animals. In that way, “We will be the machines getting life to grow all over the universe.”
you don't. you make solar panels, which are more efficient than plants at converting solar energy to electrical current, and then use it to run a space heater. Don't genetically engineer what you can engineer in silicon.
Assuming perfect efficiency in capturing whatever sunlight they get, perfect conversion to chemical storage (i.e. sugars, or any other fancy molecule with energy-intensive bonds) and a perfect conversion from that to heat. Would there be enough energy to keep the plant warm? Against a temperature difference of 40ºC+?
Ok, but then (and my curiosity is sincere) why would you need a plant to "stay warm" at 57°C. Because of the night? But that could be solved with some sort of passive solution that buffers the temperature along the day, not neccessarily producing its own heat.
Would night have to happen? In lots of orbits couldn't the plant keep the window facing the sun continuously? I assume in general staying warm is a plus for making reactions (like photosynthesis) easier and faster, so better for building a big living colony.
If it's an asteroid what is night even like? It seems like it'd be a lot less extreme than a planet.
I could imagine a plant that walks along the surface to stay in the sunlight.
Maybe lay down roots all over the asteroid to do the refining and have long tethered leaves always in the sun.
If the leaf stalks can grow at the same rate as the asteroid rotation, just keep growing and wrapping the asteroid until you're left with nicely spooled refined materials.
I don't think a hot blooded plant is practical or necessary, but there is enough energy that it could be possible.
I am obsessed with Venus and I have thought a lot about acidophilic prairies floating on the Venus atmosphere. They would be indistinguishable from land if you are standing on top of them, you can build your Hobbit house there. It is an amazing concept!
You will have to deal with the insane thermal flux too. Even where the atmosphere is Earth-like in temperature, you will have a very hot radiator below you and frozen space above. (If you were in low Venus orbit, and could "stick your head out" of the spacecraft, Venus would feel as warm on your face as the noon sun on Earth. On the night side. That's how hot the planet is.) So for anything larger than algae, even in the convective atmosphere, you're going to have a side that's burning hot and a side that's freezing.
That doesn't mean soil for any kind of organism is as hard. There are many of them that don't need all that complexity even on our world that doesn't strongly select for it.
I don't see why we need warm-blooded plants. I had spinach growing in my garden in 2020. Usually I pull up anything in the garden and till it but in fall 2020 I didn't. Spring 2021 and there was the spinach green as emerald. All through -20C, freezing rain, snow, just all around cold weather it was fine. edit: forgot to add frost in the ground probably down 60cm or 75cm so it's also affecting roots. Spinach is cold loving but I though it was amazing. Even more impressive than grass on a lawn which often is fescue, rye, bluegrass.
Edit: we've already asked you this, and you've unfortunately been doing it repeatedly. Could you please not? If you'd make substantive points thoughtfully, that would be much better.
My favorite line of reasoning about eugenics[0]: let's just accept that eugenics is a good thing; so good, in fact, we can go back in time and give a past society the ability to decide on the physical and mental attributes of their future, our present. Who would you pick? Would you go back 50, 100, 200, 500 years to gift this power?
If you're uncomfortable with people several hundred years ago making decisions about your genetics, why should people several hundred years from now be comfortable with you making decisions about theirs?
I think one should be honest: Most people are more comfortable with making decisions for others, than with others making decisions for you. It's obvious! I think the ethical, "symmetric" stance is somewhat disingenuous.
Similarly, I do not want the government to have certain powers. But I would happily award myself these powers if I were in charge, to be honest. I would never campaign for that, of course.
This brings me to my argument against eugenics: I think in the current world, it would have horrible effects. It would increase inequality, and create suffering. But that is not a neccessity. In another society, some elements of eugenics could be useful (to be clear: I'm not talking about deciding who can procreate and not, but for example preventing heritable diseases). The thing is, we can't agree on what this better society would look like. I of course believe that would be when I was in charge, but you'd probably disagree :-).
The problem with eugenics is the coercive nature of it. People practice their own eugenics all the time - it's what we do when we engage in mate selection.
Genetic engineering of offspring is a very different postulate to eugenics though - eugenics is trying to control people's reproductive choice towards an outcome desired by an external party, whereas genetic engineering would be parents trying to get desirable traits for their offspring.
Technically I already did this when I had my first child: me and my wife got genetically tested for possible hereditary overlaps, as well as got as many screenings as were available when the child was developing.
If those tests had shown risk factors, we would have picked IVF or other options to specifically knock out those traits from being passed on. If the technology to select a bunch of genes in my child that favored intelligence, or lower risks of lifestyle disease were available, you bet I would've paid a fair amount of money to get that done too.
We would breed them to be comfortable with our having made decisions about their genetics.
Where by "we" I mean the plutocrats who make decisions about how each of us lives now, the Peter Thiels, the Vladimir Putins, the Xis, the Bill Gateses, the Kochs, the Morgans, the Stanleys, the Goldmans and the Sachses.
If there's anything I've learned from software engineering, it's that ideas seem like good ideas until they're implemented. Something seems like a good gene to select for until 3 generations later where someone else has to deal with it.
The other thing that fascinates me is navel oranges. They're delicious, but they're sterile and come with defects (the navel). We're perfectly happy to deal with those defects because the benefits outweigh it. I wonder what defects come from radiation resistant supermen.
Software engineering teaches us to identify defects and fix them, which is all fine and proper when you fully understand the root cause and the impact of the fix. But eugenic "fixing" of genetic "bugs" is more akin to deleting a whole module because you think it caused an error message. Maybe the error message goes away, but maybe you'll find out later that module was doing something useful after all.
I think it is that way, the output of genes is determined by what they do together, they all affect each other's function. This is possible because they evolved together and that is why they together are resilient against changes in the environment.. It is not like a program where flipping a single bit can crash the whole program.
What kind of eugenics are you proposing? I know that the notion of eugenics has got a bad rap but I'm a bit concerned with your wording because it seems to indicate that you have in mind the kind of eugenics that gives the whole notion a bad rap.
When you say 'we could do some eugenics' do you mean the kind of top down, centrally planned by absurd edict shit that we saw from central Europe in the early 20th century that was influenced by North American culture that lingered well into the mid 20th century?[0]
Or do you mean the kind of self empowered eugenics of the late 20th century where women found themselves with newfound means to decide their reproduce destiny for themselves?
What are your thoughts on the burgeoning 21st century development where currently upperclass people are finding themselves in the economically viable position to select and potentially modify embryos for implantation?
How do you think that we as a society should bridge the gap between where we are now with eugenics and where we could be, and how does that tie into where you think we could go as a species either interplanetary or beyond?
Neither. I just thought it opens an interesting question: What happens in the long run if some parts of the world embrace eugenics and gene therapy (in whatever form), while others do not, e.g. under ethical grounds or simply different priorities.
Further class segmentation and ultimately speciation once populations have grown so far apart that they can no longer procreate.
I can't recall the title of an Australian gov't commissioned paper on the subject but this was ultimately the conclusion.
The paper also pointed out that domestic attempts to regulate these acts would ultimately be futile because people were already traveling abroad (specifically Italy) to seek out reproductive/eugenic services that were not legal in Australia.
My expectation would be a similar result in humans to what we observe in all the non-humans we’ve been selectively breeding for eons.
Vulnerable monocultures; hyper-optimisation for a specific trait (or many breeds each optimised for a different trait); morphology significantly different to the wild form, with fashion preferences leading to fundamental health issues that can only be fixed by altering the fashion (GSD hip dysplasia, pug squashed noses).
People who have to buy RoundUp from Monsanto to keep breathing or to have kids etc.
There is no limit to how bad this could go.
And like pretty much any knowledge or technique, it will be developed and used, and so the only ways to head off the horror outcome is a combination of arbitrary legal declarations to just make some things illegal or at least pointless (not profitable), and open source, putting the same powers in the hands of individuals.
It seems to me that human potential can be better realised in many ways, and eugenics is the way with probably the worst return on investment.
For a start, we could try giving as many kids as possible in the world a decent crack at doing something important. Obviously this is very difficult and complicated. But then so is eugenics.
Eugenics isn't really that complicated. We've been doing it for millennia by selective breeding plants and animals. Direct genetic manipulation isn't the only form of eugenics.
Is it really more complicated than weeding out aggression from wolves? Or the breeding that actually made corn edible? I don't think you realize how much we've changed the world by deliberate gradual changes like this across many generations.
It's totally feasible to see 10 point average IQ increases within a couple of generations if we actually did this systematically.
I’ve been doing a lot of reading on megastructures, giant black hole powered computers, Von Neumann probes, and all the other super advanced technologies, and then thinking about the Fermi paradox, and I can’t shake the feeling these are just gussied up magic by effectively godlike entities. They’re completely impractical and take some pretty big hand waving to make them sound plausible.
We’re running out of excuses. We’re either alone, or we’re effectively alone ie everyone else is forever undetectable. Meaning they’re more primitive, or stuck in some subterranean ocean or something. Either way, we’re the Ancients sci-fi stories ale we ya talk about.
> We’re either alone, or we’re effectively alone ie everyone else is forever undetectable.
Native tribes could be forgiven for assuming they were alone until explorers and conquistadors arrived.
It’s possible that a civilization millions (or billions) of years ahead of us in biology, energy, philosophy, etc. is just beyond our comprehension at this moment to even know what to look for, where or how.
Plus, we already try to make things hard to find like stealth fighters. Perhaps it’s a good idea for survival in the universe to be difficult to find.
You mean the books where magical aliens warp the fundamental constants of the universe to eliminate physical dimensions?
Even if you skip past that to the underlying dark forest idea, it’s an argument based on pure faith with zero evidence to support it. You need an all power malevolent society that works on a time scale of thousands if not millions of years, and then nit only eliminates another society for “reasons”, but also then also perfectly covers up its own existence, because there may be some other bigger bad out there. It’s about as convincing as the unicorn that’s always right behind you, but everyone ignores because unicorns are super dangerous.
Space is big. Like, really big. The galaxy could have a million civilizations more powerful than you could imagine, and there is no reason why we would necessarily be able to see any of them.
That assumes we would even be able to recognize one if we could see it.
How are all powerful, but hidden entities, that live far away, but can kill us all in an instant, any different from the evidence for the invisible magical sky daddy?
Even if I wanted to be generous, “really big” and “no reason why we would necessarily be able to see any of them” is indistinguishable from my statement of being “effectively alone”.
But why would they leave the same artifacts over and over again? Seems like a pretty boring existence for a "god". We've got blackholes, magnetars, pulsars, binary stars... and... that's about it... Seems much more likely these structures are the end result of some fixed set of physical rules than insane gods trapsing around the universe.
Also agreeing with one of the comments above about how mind bogglingly massive space is, we've been effectively "listening" to space for only about 100 years, which creates an effective "listening sphere" of 4.188×10E6 light years^3, or 0.000524% of the milkyway's EIGHT TRILLION cubic lightyears in size (even if we could listen to all directions simultaneously, which we can't!)
I mean, we've been listening to the Wow! area for 50 years now, which also hampers the kind of electromagnetic 'sweep' we could possible be doing in the meanwhile.
My overall opinion is that it's just simple not been enough time of listening.
Actually this idea seems quite interesting, it would be cool to do the calculus to figure out our effective "increase" in contact intersection as each consective second, minute, hour, day, and year goes by as we "listen" to space. Infinite overlapping spheres in an infinite 3D space... hmmmm
What artifacts are they leaving? Literally nothing has EVER been detected.
The reasons why they listen to the hydrogen line is because it’s the most easiest to detect. However, the 50 year timeframe isn’t really a problem. The entire sky has been measured multiple times in this 50 years, and nothing has been found. Unless you believe the signals passed 51 years ago, then the silence is deafening.
Could stars blacked out by Dyson spheres or other technology that completely harnesses their energy be an explanation for dark matter? Or would this matter not be so "dark" due to the heat signature?
I think most if not every galaxy has dark matter so if it’s Dyson spheres that would mean that nearly every galaxy was colonized with Dyson spheres in the same way (except ours because we don’t have evidence of a galaxy-wide civilization).
Indeed, Dyson spheres would need to release some amount of waste heat, due to the laws of thermodynamics. If there were too many of them that heat would be visible (at least to infrared telescopes,) so we know that’s not the explanation for dark matter. Same with dust and other non-luminescent matter- it’s all way more visible than dark matter has to be, somehow.
Literally every last thing in the whole universe that can radiate heat is at least as warm as the cosmic background radiation. You cannot shed any heat at all unless you are warmer than the background radiation, because you would be absorbing as much heat from it as you radiate. If you were colder, you would necessarily be absorbing more.
what would prevent an intelligent civilization from covering all other stars in dyson spheres?
and the dark matter is everywhere (almost, there're galaxies without it) which would mean that most of the universe has intelligent life but then why there's no other signals? something should've leaked/pointed at it
Any sort of Dyson-spherish thing would radiate in infrared, and not be dark at all. A long time ago somebody went looking for these infrared emitters, and found billions (and billions) of them in our galaxy alone. Turns out low-grade infrared-emitting stars and star-like things are more common than dirt. There is no way to tell them apart from a hypothetical Dyson thingy, even if there were any actual reason ever to build one of those. (Which, hint, there isn't.)
"The observational signatures of such “Dyson spheres” include waste-heat from the absorbing sphere, obscured direct star light (resulting in both an apparently underluminous star and potential temporal variations in brightness) and the effects of feedback on the properties of the star from the surrounding sphere."
So there are ways to distinguish probable Dyson spheres from the majority of these natural infrared sources.
That would depend on somebody, anybody seeing any reason to build so much as one of them.
You might imagine a playful civilization building one next-system-over to fool planet-bound hicks who actually still believe they are a good idea. The hicks restructure their whole civilization to be able to mount a trip to visit it, and when they arrive find it is all just a mock-up.
Sure, there are good and interesting arguments as to whether anyone would bother, but that's orthogonal to whether we can distinguish them from natural sources.
EDIT: but I like your idea, sounds like it would be a fun short story!
Dyson, a very smart man, saw a reason to build them. Now there may have been some revelations since his time that have made it obvious that they are not a good idea, but clearly that information has not spread widely. Care to enlighten us?
Dyson was writing at a time before people were thinking about controlled fusion as a way to generate power. Furthermore, he projected not building, but growing a biosphere spread out around a star. The notion of constructing a thing to try to gather and convert all of a star's radiation is a radical corruption of his idea.
Finally, he posited this development in the near term, while humanity remains far short of any capability that could actually be called advanced, with nothing better to hand than genetic engineering and dumb rockets.
Let's presume that the universe is full of Dyson Spheres, and the gravity they produce is what we call "Dark Matter". Well, Dyson Spheres must be built, right? So earlier in time, there would be fewer of them, and later in time there would be more of them.
When we look into the sky, we look back in time. So if this were the case, when we look backwards in time we should see more brightness and less dark matter effects, while closer in time we should see less brightness and more dark matter effects.
We do not see those patterns. Dark matter is consistent over time, as far as we can tell, and brightness from stars remains what we would expect.
Maybe this is a stupid question, but is there actually enough raw material in the solar system to cover the surface of our star and build the necessary machinery to keep it in place, collect its energy, etc.?
You don't put it on the surface of the star; you orbit at a distance far enough away to maintain a reasonable temperature. Current solar panels are about 300 grams per square meter, but there are much opaquer materials than silicon, so you can probably get down to a hundredth of that. A sphere at the radius of Earth's orbit would be 2.8e23 square meters and thus at 300 grams per square meter 8.4e22 kg. Earth's moon masses 7.3e22 kg, while Jupiter masses 1.90e27 kg. So there's at least five orders of magnitude more raw material than you need.
If you happened to live in a planetary system without adequate gas giants, you could probably find some way to scoop mass off the surface of your star or capture it from coronal mass ejections, then use fusion to transmute it into the materials you need. Even Sun is 1.90e30 kg, and it's rather small as stars go.
There's plenty. The vast majority of the 'shell' would be solar concentrators - basically aluminium foil or something like it. You can make a LOT of that by dismantling a few asteroids, never mind a planet or two.
Isaac Arthur's youtube channel goes into this in some depth (and is generally excellent, IMO). Here's an episode on Dyson Spheres:
It's probably very difficult structurally to build an actual sphere, since the poles would not have any orbital velocity and the whole sphere would want to flatten. Unless there is a way to do some kind of anti-gravity that humans just haven't discovered (which is a possibility that seems plausible).
But there is also the Dyson swarm, which is like a starlink constellation orbiting a star and designed to collect as much energy as possible.
Anyway I don't know the answer to your question, but if we ignore structural problems with a sphere we could imagine a material a few atoms thick, like a giant carbon nanotube structure. Then one wonders how much material there is in Jupiter as an approximation of total matter in the solar system. I will leave the calculation as an exercise to the reader. ;)
I believe Dyson spheres don't rotate, so they just have to be able to handle the stress of the central sun pulling uniformly on the surface.
Per the Ringworld not being stable, I think the same math applies to the sphere as well as the Ring, so the sphere will need attitude jets to maintain position with respect to the central sun.
Dyson swarms seem drastically easier to construct. We could build one example of that habitat fairly soon!
Ahh a non-rotating sphere makes sense! If it is light enough then solar pressure could help keep it up too, and it could have openings to adjust pressure which would serve as attitude jets. Hmmm this does seem possible after all, thanks for the tips!
The only conclusion we should make right now is that the Dyson Sphere doesn't exist and we're the only intelligent life in the Universe, which makes it all more terrifying.
evolution seems to be a constant fight for energy, this can be even expanded broadly: the universe is all about gathering energy. So not sure that someone would be fine with a constant limited energy supply. Plus those supplies eventually run out
Perhaps civilizations with eternally increasing energy demands inevitably encounter a great filter of their own making, while civilizations that learn to live with more modest energy requirements live on in peace and silence.
agreed, but where do you get a lot of energy from? stars are the only answer seems like right now, nothing else produces/radiates energy in the universe in quantities needed
Correct it’s not even hard to imagine in our lifetimes humanity will have a solid footing to reject the cost/benefit of Dyson Spheres based on existing alternatives.
Dyson spheres (actually not spheres, in any sense, originally) were a clever idea, but it seems terribly parochial, not to say gooberish, to assume that anybody sophisticated enough to build such a thing would want one.
More specifically, anybody sophisticated enough would dismantle their local gas giant and ice planets and convert them directly to energy, and leave the local daystar entirely out of the transaction.
An advanced civilization will exist almost exclusively in the far outer reaches of a solar system, where the daystar provides nothing more than gravitation to keep the Kuiper belt organized. The most valuable resource for this advanced civilization will not be energy, which is cheap, or materials, which are cheaper, but cold. The abundunt cold out in the Kuiper Belt is essential to not being vaporized by the waste heat of the high energy processes more or less advanced civilizations cannot resist indulging in.
ah, I see, take a gas giant and put into fission through whatever process you want. Still seems like a lot of energy to go through until you can do fission while the star is right here
We already have infrared telescopes. There are literally billions of infrared sources already known in the immediate neighborhood. I promise you none of them are Dyson spheres.
Always have to comment on the meme Dyson spheres posts with the following: has anyone ever thought, for one second, that a civilization capable of building these massive energy systems would actually be capable of generating energy in other different ways that we can't even imagine? This whole "Type I, II, III" civilization crap is stupid because it is based off one paper, of one guy, who had a creative idea. Props to him for the creativity, but millions of scientists every day have possibly creative ideas about space fairing civilizations. Its like sci-fi novels creeped into real science. Literally ape brain to just "wrap a star and capture its energy!"
I think most people "like" the idea because it's so tangible. But that doesn't make it any more or less likely that it actually exists or makes sense.
I think it's not only about energy generation but what would massive civilization without dyson spheres imply:
1. sidestepping thermodynamic laws - to allow massive energy use without detectable waste heat
and/or
2. sidestepping time lags - so that the system does not need to be bunched as closely together as possible to allow for efficient communication and flows of material
Dyson Spheres are fundamentally unphysical. The stability constraint on a complete sphere turns out to be less of a problem than it might seem, but there are still huge issues with stresses - Sphere Quakes.
And before you can build a full Sphere you have to build a partial Sphere. Which is where stability will really kill you.
Dyson Swarms might be more practical, but you still have a computability problem because you have an insanely huge number of objects in orbit and you somehow have to keep them from colliding with each other.
Not so much a three body problem as an n body problem. With a built-in light lag delay of (at least) minutes.
I'm not sure if anyone has modelled that, but it would be hilarious if the computing and station-keeping power requirements turned out to be a significant proportion of the available energy,
But you did not exhaust all the options. What about spherical constellation of energy gathering sails that stay mostly in place? Can autonomously maintain their position with help of solar wind.
> spherical constellation of energy gathering sails that stay mostly in place?
Wait, what? You can't have a spherical constellation of unconnected stuff that mostly stays in place, that's not how orbits work. You can have a single orbital ring, but a sphere consisting of many circular orbits would have these orbits intersect with very large relative movement. If you're thinking about non-rotating constellation where the gravitational pull is balanced by solar wind, the problem is that they have gravitational interaction with each other and the planets so it's inherently unstable, they would "want to clump up" and as soon as they do, the balance is disrupted as the same mass has less solar pressure and it starts to fall into the sun.
To me it sounds like "flight heavier than air is impossible!!!!".
Why would a device that has 1kW/m2 at its disposal at all times, be fundamentally unable to counteract gravitational interactions? We are not talking about planetary gravity wells here but much weaker ones.
It’s probably just that colonizing the entire galaxy is really hard and no society ever has an economic need to. Populations don’t expand exponentially forever, the recent explosion is an effect of the industrial revolution, and any species that gets a certain size breaks up into subspecies and starts competing with each other.
There could very well be individual dyson swarms out there and we haven’t seen them or haven’t realized that’s what they are. But building them around every star in the galaxy is something I’ll never understand why it’s taken as a given.
Frequently; that comes up in basically every Issac Arthur video on the topic.
Unless such a civilisation can dump the waste heat as something other than infrared light or send that waste to somewhere other than the visible universe, it’s still extremely visible.
The odds that anybody smart enough to be able to build such a thing would not be smart enough to recognize what a bad idea it is, is closer to zero than any mere human can conceive of.
People smarter than you, like Freeman Dyson, have thought otherwise. More generally, a human putting long odds on what anybody much smarter than mere humans would do is self-evidently a way to lose bets. Can you imagine a dolphin or a crow successfully predicting the outcome of the US's withdrawal from Afghanistan?
Any crow, dolphin, or half-wit would have predicted US failure in Afghanistan. Donald Rumsfeld was Secretary of the US DoD at the time of the invasion. There is no public evidence that he predicted failure.
Freeman Dyson never proposed building anything even vaguely like what is called a Dyson Sphere, and was famously irritated at having it attributed to him.
> Dyson had also proposed that the search for extraterrestrial intelligence (SETI) programs should “search for sources of infrared radiation” to “accompany the recently initiated search for interstellar radio communications.”
I remember some discussion of this point in his autobiography. He wasn't talking about the Star Trek version, but certainly the intercept-all-the-sunlight constructions we're talking about.
Anyway, intercept-much-of-the-sunlight. It would be seriously impractical to arrange to intercept radiation leaving a star at high latitudes. And, being made of trillions of independently-orbiting tree-like things, there would be as many small gaps where native starlight would squeak out.
Not mere trillions, on the order of 10²¹ if we're talking about trees similar in size to existing trees. The latitude is irrelevant, because the rotation of the star has an insignificant effect on the orbits of objects at distances hundreds of times its radius. Yes, there would be many small gaps. That doesn't significantly affect the utility of the artifact.
All of this is obvious to anyone who does the math.
There is no reason to assume that trees in a weightless environment would be limited to sizes seen under 1G acceleration. Metabolism would need to be very different, too, because evaporation is not available to drive transport.
Obviously the rotation of the star has no effect. But the need to move between habitats precludes substantial differences in orbital plane (look up orbital plane maneuver, these take exceptionally large delta-V), keeping things close to the ecliptic.
Doing the math produces a picture very different from what you imagine.
If Alice is going from Arcadia Habitat to Zenith Observatory, and Bob is going the other way, and they're of equal mass, it's a momentum exchange. In a developed solar system the transport network could make a lot of hay out of this principle.
Even if the cities do cluster in one plane, that doesn't imply the power stations will.
Probably if you believe that dolphins and crows understand human politics and battlefield tactics, and you believe trivially falsifiable things about Freeman Dyson (https://en.wikipedia.org/wiki/Freeman_Dyson#Dyson_sphere), there is not yet any point in talking to you about subjects like this. Maybe in five years.
Based on our understanding of science. But 200 years ago the idea of having a conversation with someone 1000 miles away seemed quite impossible. Is it so hard to imagine that out of the possibly hundreds of millions of civilizations in the Milky Way, someone has found a way to extract energy from the universe in a way which seems physically impossible to us?
I’m always very open to the idea that there could be a lot of physics we don’t understand yet. We could be at 0.1% of an understanding of the basic laws of the universe. I’m not saying I think that is likely or unlikely, but I do think it is possible.
> But 200 years ago the idea of having a conversation with someone 1000 miles away seemed quite impossible
In 1822 the Chappe optical telegraph had been in use since the Revolution, and the electric telegraph was ~20 years away. You'd have had to be singularly unimaginative not to envision an eventual extension to instantaneous voice.
Ah, I guess I was referring specifically to radio transmission. You could say 400 years ago if that matters. A distant civilization could be 1 million years ahead of us.
Eh, it's typical retrofuturism type stuff, extending current technologies quantitatively rather than trying to predict categorical changes in available tech.
Also the issues of dyson spheres aren't that bad. they could for instance channel the heat loss energy in a narrow beam out of the galactic plane so at least they'd be hard to spot by other galactic observers.
OK, let's talk about energy generation for a minute. If we assume there exists some completely new physics, then... that could be anything. Advanced civilizations could take on any form. We can speculate all day about magic and elves too.
If we don't assume any new physics and / or thermodynamics, then that constrains the discussion a lot. We have two basic ways of generating a lot of power, fission and fusion.
Fission uses fissile materials, which are relatively rare, not just on Earth, but in the Universe at large. There's plenty enough for us at our current energy generation needs, but not nearly enough for a galaxy spanning civilization. That leaves us with fusion.
Fusion reactors, as currently conceived use Helium-3 or something like that. There's enough of that around the solar system to power a civilization for a long time, even though the mass of oddball elements like Helium-3 make up a very tiny fraction of the total mass of the solar system (which is mostly the Sun with a smidgen of Jupiter).
Most of the solar system's mass is plain hydrogen: one proton and one electron.
Is it possible to fuse most / all of this mass in the solar system? Yes. We won't go into the details, but trying to fuse regular hydrogen (regular protons) together is highly impractical outside of the core of a star. Preferably a red dwarf type star which can more completely burn its fuel than our own Sun will, and live a lot longer to boot (a trillion years vs. ~10 billion for the Sun).
So now we're talking about some kind of solar collectors, and if you want to collect _all_ the energy from a star, you want a sphere of some sort. Or a swarm of objects in orbit achieving the same effect.
> and if you want to collect _all_ the energy from a star,
For what? What are you doing with it? Not to forget the fact that all energy used eventually turns into heat. All of it (with the exception of electrochemical transformations). You're bringing all of that into Earth you're cooking everybody alive.
How are you bringing that energy from the sphere to (wherever place)?
Putting solar panels on Earth itself works much better. Heck, make a Dyson sphere on Earth (facing outside), that makes more sense.
It is typically assumed that by the time you are making a Dyson swarm, that most life exists digitally. And spread out through the solar system.
So in the best case scenario, you are powering computronium, upon which trillions of sophonts live out their digital lives. Hopefully doing some science, or at least playing some interesting games. A vast distributed network.
In the worst case scenario, Blockchain and spam emails.
Either way, people will put that energy to use.
With a Dyson swarm, energy is received on the inside, towards the star, and heat is radiated outward. Lower power systems can run off the heat radiation of the inner swarm similarly. It is all eventually released as very low level heat, but diffused across the entire outer surface of the swarm. No hotspots... because someone would come along and use it.
The Earth would also likely be deconstructed by this time, so don't worry about the biosphere, there won't be any.
You are not pushing a light sail ship to another star system, sorry.
Light sails are "theoretically" possible but you don't need that much energy to push something that's feasible to push.
Or better, there's a better source of light radiation: the sun itself. No need for a laser, just use a focusing mirror and you can have 100x more pressure than just from the sun itself.
Light from the Sun isn't coherent, and you can't focus it with mirrors very far away. Lasers have many orders of magnitude less divergence when talking about distances measured in light-years.
> Light from the Sun isn't coherent, and you can't focus it with mirrors very far away. Lasers have many orders of magnitude less divergence when talking about distances measured in light-years.
To expand on your point, those characteristics become even more important when using the light received to decelerate at your destination, though it is worth noting that there are alternative means of deceleration that don't have the same requirements (eg. electric and magnetic sails).
Why not? Light sails can reach 10% the speed of light, and sending out thousands of colony ships in multiple directions seems like a feasible way to colonize a galaxy relatively quickly.
As the other poster mentioned, harnessing the sun's energy and turning it into a better form suited for light sails is the way to go. Sailing on the solar wind within a star system is a different tech with a different purpose.
> Heck, make a Dyson sphere on Earth (facing outside), that makes more sense.
I’m missing something here, because even if we decided to build a Dyson swarm of course we are going to start with putting solar on and around Earth because this is where all the stuff we care about is.
It's premature to say what's practical with fusion and what isn't. It's entirely possible that we find a way to build an efficient hydrogen fusion reactor. In which case it might not make sense to travel so far away from our planet just to collect energy from photons when that costs more than just doing the fusion ourselves. Remember it's actually more expensive to travel towards the sun than away from it (because you have to shed velocity relative to the starting velocity on Earth.) It's too arrogant to think we know the answer to that now.
> It's premature to say what's practical with fusion and what isn't. It's entirely possible that we find a way to build an efficient hydrogen fusion reactor.
Would it not surprise you that fusion in general has been studied extensively by physicists for nearly a century? It takes very high temperatures, pressures and quantum tunneling to get two protons to fuse.
It doesn't surprise me. Your arrogance does though, I didn't expect you to double down on an unreasonable position. How can we possibly know what we don't know yet. Not about how fusion works in theory, but about the limits of the economics of fusion reactors at any point in the future.
What I'm saying is it's too soon to say what's possible with fusion and what isn't. We don't even have a break even reactor yet. We can even say for certain that we ever will.
> It doesn't surprise me. Your arrogance does though, I didn't expect you to double down on an unreasonable position.
I'd give your criticism some consideration if I thought you had even the slightest knowledge of what we're talking about.
Let's talk about the core of the Sun, where p-p fusion takes place. Remember, I said at the top: no new physics.
The core of the Sun is hot, like really, really hot. How hot? 15 million Kelvin. So no solid material ... made of atoms ... can be anywhere close by because it would vaporize. You can talk about active cooling or whatever, and that's not going to help. But let's assume we have some magical material that can deal with that temperature, and keep going.
We're going to skip the pressure that really hot plasma is under, and assume we have terrifically awesome magnetic confinement that can handle that. We don't actually, but let's move on.
The other problem with 15 million K is that all that energy wants to radiate away. Yes, you want to absorb some of that radiation (hard gamma, by the way, very nasty) as part of the energy generation process, but if you let the plasma cool off, the reaction rate drops. "Cool" in this context is relative, at 7 million K, the reaction rate is very close to zero.
The last problem we will talk about today is volume. The above conditions get us a fusion power density of... 276 watts / cubic meter. To have a fusion plant that generates 1GW of power, we'd need to contain a cube 153 meters on a side of 15 million Kelvin plasma.
Oh, wait, that assumes the magnetic containment and everything else requires zero power to run. So we'll have to go bigger, much bigger.
Are you starting to understand the scale of the problem... trying to design a proton - proton fusion reactor?
I am not the arrogant one, I'm just listening to the fusion scientists who have been studying how all this works.
> We don't even have a break even reactor yet. We can even say for certain that we ever will.
And here you are expressing doubt that we'll achieve even the easiest kind of fusion reactor. We have achieved fusion, just to be clear. We can reach the temperatures and pressures to see some reactions.
Assuming civilization does not collapse (climate change, war, etc) we will be able to engineer a fusion reactor that is some kind of practical.
Edit: Actually, the material issues mentioned above probably won't be an issue, as long as the confinement is good. You still have the issue of keeping the plasma hot enough for long enough.
But the scaling issue doesn't go away unless you go with even higher temperatures and pressures.
> I'd give your criticism some consideration if I thought you had even the slightest knowledge of what we're talking about.
Doesn't sound like an arrogant person to me...
FYI I understand how magnetic confinement fusion works at a high-level, as a non-scientist.
There's a lot of assumptions you're making here. First that we need hydrogen-hydrogen fusion. Many current reactor designs use deuterium and tritium (nasty stuff tritium.) It doesn't have to be plain hydrogen, it just has to be elements common enough that we won't run out (or that we can breed using neutrons - that gamma radiation you talk about - from the fusion reactor.) Some designs are more exotic with fuel using isotopes of helium, lithium, boron. Second many current reactor designs use a plasma temperature well above 15M K. I've heard of 100M K and that's not an upper limit.
But you're also making assumptions about the volume of a reactor - we don't even know if magnetic confinement fusion will end up being the best design, but if we assume it does - then stronger magnetic fields really decrease the volume required. In fact development of stronger magnets based on high-temperature superconductors may be the biggest breakthrough in fusion research in the last decade - see https://news.mit.edu/2021/MIT-CFS-major-advance-toward-fusio...
> And here you are expressing doubt that we'll achieve even the easiest kind of fusion reactor.
We don't have a break-even reactor yet by the way - we have achieved fusion for short periods of time and by putting in far more energy than could be produced. That milestone is probably still at least a decade away.
My point again is that we don't know enough to be able to say what's possible and what isn't. History is littered with people arrogant enough to say what we can never achieve and humans keep surprising. Sometimes even things that seem impossible - like detecting planets around other stars when the physics of optics is very clear that an optical telescope could never directly image a planet in another solar system. That was wrong on two fronts, one it doesn't account for gravitational lensing, and two it didn't account that we might cheat and detect planets indirectly. And so the arrogant people were wrong again. Don't make that mistake.
> I think there are more. Like radiation from evaporating black holes.
Evaporating black holes?
Yes, if you are willing to wait a very, very long time, and have collectors over a large area.
However, if you want to get stuff done before your protons evaporate, you could instead throw matter into a black hole, thus increasing its mass. The radiation given off by the accretion disc is substantial, and can be collected... over a large area.
IIRC, the mass-to-energy efficiency is something like 40%, which is really good.
I mean, we're talking about timescales and construction projects like Dyson spheres. It's entirely feasible that people with such technology could create microscopic black holes that evaporate quickly for these purposes. Hawking radiation at this scale is substantial.
Ah, yes, I do recall reading about that somewhere.
That is an interesting prospect, with a very high mass-to-energy efficiency. Of course it requires careful management of inflowing matter. And you can shut if down if needed by stopping the inflow, assuming you have enough stored energy to recreate the micro black hole sometime later.
A Dyson sphere is technically possible without any new physics with a few decades of work. By contrast, while we have the physics to analyze how black holes much smaller than a proton would behave, we have no plausible way to go about making one.
Dyson sphere as conceived by Dyson himself is a swarm of orbiting objects, not a literal sphere around a star (that's Star Trek interpretation). We could start sending out solar panels to orbit the Sun today, and start adding space stations later this/next decade.
It doesn't count as a Dyson swarm until it captures a large percentage of the sun's output. As I said, that science and the computational power needed to coordinate those kinds of orbital mechanics are beyond us.
It doesn't all have to be at a single distance from the Sun. Some objects can be as far as Earth is and other objects can be at Mars level, at Merkur level or wherever else. There's plenty of space for this to be too hard.
That doesn't matter if we're talking about scenarios where a significant fraction of the sun's surface area is covered. That requires enough mass for each fragment to make such a loose "shell" that they would influence each other gravitationally and perturb each other's orbits.
Not to mention that that much surface area would catch a lot of solar wind, causing all sorts of rotational moments that will need constant correction. The control theory needed for this sort of thing is complicated and N body problems are undecidable in general.
It would catch approximately all the solar wind. "All sorts of rotational moments that will need constant correction" means that, if your orbiters are thin enough, they don't need reaction wheels or thrusters to change course to avoid an imminent collision — just solar-sail louvers. An occasional collision is unimportant to the viability of the system, like dust settling on solar panels, or dermis cells dying in a follicle to grow hair.
N-body problem instances are never undecidable in the automata-theory sense; you can answer any question about the future trajectory from given initial conditions straightforwardly, if slowly, with interval arithmetic. The question of whether initial conditions exist that evolve to a given result is undecidable, but as with undecidability results in general, we do not need to decide it in order to build a working system, only to prove the optimality of a given program.
You seem to be making up reasons to justify a preselected conclusion without bothering to think about whether they are true or relevant or not, and I wish you would not do that.
Not significantly. Do the math: a thickness of 100 microns with existing silicon solar panels, or perhaps as little as 0.1 microns, out of, say, 1 AU (1.5e11 m). We're talking about filling 2e-15 of a 1-AU sphere with solid orbiters, totaling roughly the mass of Earth's moon, if we're using current silicon solar cells, and potentially a few orders of magnitude less than that.
You could use a smaller or larger radius, resulting in higher or lower irradiance and higher or lower orbiter density, but we have a lot of experience with different kinds of solar panels at 1 AU, so we know it will work.
No, there's no problem with orbital dynamics, control, computation, communication, or any of that nonsense. 50 years ago those were potentially challenging problems, but not now. Today the only remaining obstacles for a Dyson sphere are manufacturing and politics.
It's just a bunch of automated drones flying in formation. Trying to calculate their orbits ahead of time in any kind of detail would be a fool's errand, instead we'd just use solar light pressure to steer them as needed (they would be very thin, there's no point to making them thick).
With really thin sails (0.78 g/m^2) they don't even need to orbit, as they can use light pressure to compensate for gravity (what Robert Forward termed a 'statite'). The light they reflect hits other sails on the other side, but this isn't a problem if they are distributed uniformly.
Existing proposals use a plumb bob mechanism or directed light traversing the ergosphere in analogy with sound amplification via linear or in this case rotational energy transfer rather than relying on the feasibility of a complete sphere to absorb any randomly directed radiation from the interior or accretion disk: https://news.ycombinator.com/item?id=30402679
I definitely agree with you. I’m not a physicist but I did watch a ton of pop sci growing up and saw so much stuff about Dyson sphere, Fermi paradox, etc. I got so bored of it and hate how it drags down most discussions about potential alien life etc. The Fermi Paradox itself was supposed to proof we’ve got something wrong, not that we’re alone in the universe and something scary lurks.
I think the answer may be that most civilizations never need or want to colonize everything in sight. It could also be political: no species gets to the level of being able to build structures like this without breaking up into competing polities. We think about colonizing everything because we’re still in the mode of a creature who evolved on a planet and spread out everywhere.
It’s probably the case that with fusion dyson swarms aren’t used due to the opportunity cost of building them. In 1-200 years we’ll find the idea of surrounding the sun with metal as laughable as there being canals on Mars.
I agree. A hyper-advanced race would probably want to disassemble the star and use its hydrogen for something more efficient than the main-sequence nuclear process, which is pretty wasteful.
Speculation what form future tech takes should have be broad and uncommitted.
* Given our current knowledge, Dyson Spheres are essentially impossible (just lesser-known point is that unlike planet, full Dyson Sphere or Ring World would not be attracted to the star that it would be built around, so it would have to be guided to move with it - see Larry Niven's Ring World Engineers).
* What a civilization would do with all the energy, whether it would want it, etc are other unknowns.
As you say, turning one person's clever idea into a whole research program at the very least neglects other great scifi novels.
If a Dyson sphere captures a large proportion of the radiation from a star, what is the destiny of that energy?
It gets converted into other kinds of energy, and eventually becomes waste energy, ending up as low-grade heat. Hence the search for infra-red sources. But the amount of energy that a Dyson sphere absorbs must be equal to the amount of low-grade heat it radiates; so I'd expect a Dyson sphere to be very bright in infra-red - much brighter than brown or red dwarfs.
I just did a quick look through the doc but it does not appear that they take into account that Dyson shell elements would try to radiate waste heat directionally to the north and south of their orbits as to avoid too much thrust from radiation that may alter their orbital paths or the paths of other Dyson shell elements.
The signal this would create to an outside observer I think would significantly change the heat signature and periodic changes, depending on our observation angle to the star.
Surely a Dyson sphere would not emit what we naively expect. Look at us, we can speculate about these and even try to spot them but are millennia away from building one.
What if the external shield of the sphere would be artificially heated to 4000K or higher ? Completely invisible.
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[ 2.6 ms ] story [ 272 ms ] threadJokes aside, is there really any practical value in this sort of research, or is it the kind of thing that we do because it's interesting and kinda cool? Don't get me wrong, I think it's valuable for that alone, but...
In many ways it is too early to do this research, so it is a kind of art (as is a lot of research, imho). As long as only a few people do it, it's cool and useful so we can be aware of our potential future.
On the other hand, since we have no credible evidence of extraterrestrials, it would be surprising to find a civilisation so advanced to build a Dyson sphere. If they can build Dyson spheres, wouldn't they already be all over the place?
Ok, I suppose I should actually go read the paper now...
Would such a civilization spread to more than one star is actually also a question, or would they control their population rationally stay on their Dyson sphere and only start to move when the star had less than 100,000 years left to go.
Only some Dyson sphere variants, like Shkadov thrusters, are primarily conceived as ways to move around. Which personally seems to me less likely, is a civilization, as well as the ability to construct these objects, also going to have a species level interest in going exploring?
Check your math: this galaxy is ~10^5 light-years in size and ~10^10 years in age.
1. Not control their population for some reason.
2. Had some sort of interest in exploring.
3. Implicit also in the speed of light thing, would find it really interesting to send a portion of their population to the next available and suitable star which might be enough light years away to make communication impractical. I mean for our civilization there is some level of argument that says it would be a ridiculous idea to move to a new solar system and we have an intellectual exploratory streak in our species.
I mean we are currently not at the level of being able to do a Dyson sphere, it took us 4.543 billion years (age of earth) to get to the part that somebody could conceive of it. There is also some discussion as to whether or not our civilization is going to last, so given that and the other things I said it seems unlikely to me that any Dyson sphere civilization would actually build more than one, but maybe some build two because binary stars or some other weird circumstance which makes it worthwhile to do.
on edit: if we get to Dyson sphere building capabilities which seems really unlikely, will we build more than one? How many more?
So again, still haven't heard any argument why an alien civilization achieving the ability to build Dyson spheres, even if they did so far enough in the past that they would then have adequate time to traverse the galaxy afterwards, would then have to be everywhere?
yes, there is, if the achievement of Dyson sphere building happened long enough in the past for there to have been sufficient time. 50,000 years ago even, no. The length of human civilization is 6000 years approximately, what if this civilization much, much older than ours 6000 years ago just started building it's first Dyson sphere. For some reason the assumption is that it was far enough in the past that they COULD be everywhere if they wanted to.
But then the phrasing is not that they could be everywhere but rather they would be everywhere, hence no civilization has built Dyson spheres. A lot of this theory that the aliens will go about building lots and lots of Dyson spheres seems based on the assumption that they will be a lot like us, but actually I don't even think we would ever build more than one. If we built a Dyson sphere it would be because we were at the point we needed the energy and we had the technology to do it of course, and we had a political system that could harness everyone to do it. But once we had the Dyson sphere I am not sure we would ever be at the position were we would need another one. Since people tend to have fewer kids the higher their standard of living it may be that with the standard of living of Dyson sphere civ that our population would be at replacement level, that is to say we would never need to move from one Dyson sphere until the sun was just about used up.
So again, sure there is sufficient time with waves of colonization (started far enough in the past) - but waves of colonization assumes a species that has a colonization urge and perhaps one that has a colonization urge greater than that of humanity. That's a pretty big if, considering all the other big ifs in the whole building a Dyson sphere scenario.
Galactic orbits are far more chaotic than the sedate stable orbits within the solar system - stars closely approach each other on a somewhat regular basis.
They’re crappy computing devices. Even if you figured out how to program one — and that’s an “if” that would make Sagittarius A* look like a neutrino — there’s no way to read the information out except Hawking Radiation, and that would take 10^70 years.
https://youtu.be/0GLgZvTCbaA (8:36)
I figure they'd have to be.
They'd need more than a solar system's worth of raw resources to build the sphere. They may need more than a solar system's worth of resources just to build the tools and craft to be able to build the sphere. They're going to need an insane amount of production facilities for various components, and that's going to take a massive amount of resources. That's going to require exploring quite a bit of a galaxy.
The number I’ve seen quoted is 50M years to colonize the galaxy: http://www.sentientdevelopments.com/2012/01/new-mathematical...
> they calculated that any galactic empire would have spread outwards from its home planet at about 0.25% of the speed of light. The result is that after 50m years it would extend over 130,000 light years, with zealous colonisers moving in a relatively uniform cloud and more reticent ones protruding from a central blob. Since the Milky Way is estimated to be 100,000-120,000 light years across, outposts would be sprinkled throughout the galaxy, even if the home planet were, like Earth, located on the periphery.
It’s actually so fast that advanced civilizations would have had time to colonize the galaxy and go extinct many times over without us noticing.
Or maybe their spheres were built so long ago they’ve already collapsed and been consumed by the stars again.
It’s a great mystery and interesting thought experiment though.
Our ancestors from 50M years ago are all extinct. So a civilisation spreading through the galaxy would have evolved in all kinds of different ways. It's not obvious to me that these diverse evolutionary strands would all still be interested in Dyson spheres, or space travel, or even astronomy.
There's a belief that's hard to shake off, that the properties humans have that we think most important represent some kind of evolutionary pinnacle. Typically, those properties are language, and a large brain for processing language. But if language and a large brain are really such great evolutionary advantages, why are humans the only creatures on Earth that have evolved those properties? Possibly language and a large brain are an evolutionary backwater.
At 0.25% of the speed of light, it would take us 1,600 years to reach Proxima Centauri; but it might take a lot longer to reach a star with habitable planets. We'd definitely need generation ships. After (say) a million years, we'd presumably have evolved to adapt to life on generation ships. It's not obvious to me that such adaptations would leave us fit to inhabit a planet. And perhaps adaptation to life on a generation ship means adapting to eating your fellow passengers.
Given the history of humanity, I find it hard to believe that the population of a generation ship could survive as long as 100 years without war breaking out on-board. We've had large brains and language for about 50,000 years, as far as I can tell; we've been warring the whole time. Maybe large brains and language pre-dispose us to war? If that's right, then it seems unlikely that intelligent life would ever spread far from it's planet of origin.
I'm very sceptical of the idea that any "civilisation" could ever spread far from its home planet. There are two things that we refeer to as a civilisation: a culture, and a species. Culture changes very quickly - over a single lifetime. But on a scale of millions of years, speciation is also pretty quick. So I can't see how any kind of homogenous civilisation or species could spread through a galaxy. They would have diversified before the train even reached its first stop.
So I don't have any insurance against being kidnapped by aliens.
Only two minor nits:
> why are humans the only creatures on Earth that have evolved those properties? Possibly language and a large brain are an evolutionary backwater.
Nearly every animal has language, for cooperation, competition, raising their young or to find a mate. Bees, whales, primates, birds, etc. all communicate strategically with some type of language.
> Given the history of humanity, I find it hard to believe that the population of a generation ship could survive as long as 100 years without war breaking out on-board. We've had large brains and language for about 50,000 years, as far as I can tell; we've been warring the whole time.
There’s been war somewhere the whole time, but not everywhere. Costa Rica, Iceland, Panama and several minor countries have no military: https://en.m.wikipedia.org/wiki/List_of_countries_without_ar...
It’s possible to find many countries who have not fought wars in the past 100 years. If you look more narrowly it’s possible to find communities unaffected by local war in hundreds or maybe even thousands of years (in other words, they fought a war but did so by traveling great distances, not fighting each other).
A ship would be much more like a tiny, isolated island colony rather than the geopolitical tensions that dominate the news.
Finally, wars rarely result in the extinction of both sides. Even if there was a large scale conflict it would likely be resolved prior to social collapse. There would be little incentive to kill so many of your fellow crew to the point where you’re putting every survivor at risk.
> Nearly every animal has language, for cooperation, competition, raising their young or to find a mate. Bees, whales, primates, birds, etc. all communicate strategically with some type of language.
There is currently only one species on Earth capable of even imagining the things being discussed here. On the other hand, it seems there may well have been more, but the others are now extinct.
One of these issues only we are discussing is the evolutionary viability of those abilities, and the fact we can do so suggests that it is, to some extent, up to us whether or not they will be.
Yes, I elided that bit, in the aim of brevity. I think there is a difference between human language and animal languages, in that human language is "creative" - we can freely create new utterances with new meanings, and expect to be understood. We know this of human language, but I would be very interested to learn of evidence of it in other species (chimps come close).
But I think the cones thing is still interesting; it means that for any given maximum travel speed, there must be other civilisations that can never know anything about you, nor you about them.
There is no need for all, or even most, of the civilizational variants to retain those characteristics. As long as some variants do, civilization would continue its inexorable interstellar spread, it would just end up being lumpy rather than a relatively even wavefront.
Indeed, survivorship bias would seemingly tend to conserve the required characteristics and possibly start constraining the ways in which civilizational offshoots can vary. And it isn't hard to imagine stay-at-home variants succumbing to the influence of later arriving spreader variants to become spreaders once more.
Once it is done, possibly much much much later, somebody may stumble upon it and use it in some creative (and unforseen) ways for other research.
On the other hand if you give any probability to alien existence, then this is very much practical already in the search for them.
Also I think science works the way that you use your fantasy to come up with outlandish things, and then try to rule them out with logic.
It's difficult to imagine a discovery that would have more practical import than the discovery of an extraterrestrial civilization.
But anyway looking for Dyson spheres will not reveal any extraterrestrial civilizations.
To make the point, literally nothing can be classified as "discovered" under your rules because any alien civilization may know about everything we'll ever find or figure out, and if they know about it we can't have discovered it.
Columbus was a murderer and people in America before he got there deserved way better but this type of nitpicking correction is just noise if you don't even say what is a more appropriate phrase.
Why, yes, of course - even in the immediate short term the ships returned from expeditions with gold and slaves; and from the very start the exploration voyages were planned and funded solely as a practical endeavor for trade and looting, not as an intellectual curiosity.
Any advanced form of civilization that can build one, probably figured how to do fusion efficiently locally and doesn't have to build these insanely inefficient energy harversters.
Keep in mind that the sun is very inefficient at energy release.
Dyson sphere prediction is like predictions in the 1800s how we would have coal and steam powered airships to travel around.
The reality is that steam via coal fire is too inefficient. Coal is just too heavy. Jet fuel is much more efficient/energy dense and not need to build giant airships.
Same with any advanced civilization. Dyson spheres just don't make sense, but they sure make good sci-fi movies/stories for the gullible.
The likeliest case for a Dyson Sphere civilization would be some sort of solar powered Gray Goo von Neumann replicator.
To reproduce such heavier elements in fusion reactors on earth would require, likely, a much higher energy than the output.
Also: the Pacific, Atlantic, Indian, and Arctic oceans are made of water, which has hydrogen in it. Also all of the Antarctic and Greenland ice, the Great Lakes, Caspian Sea, Lake Baikal, and Lake Victoria.
Most likely you would use up Neptune first, and save Jupiter for later.
The view that they wouldn't do both is premised on the assumption that they won't need or want that much energy, combined with the assumption that the problem of disposing of the waste heat makes the extra energy not worthwhile.
"Why buy the loaf when you get free slices?"
He speaks to the subject in this excellent interview playlist, link is to the specific Dyson Sphere part:
https://www.youtube.com/watch?v=GPB775_BZlw&list=PLVV0r6CmEs...
"Any sufficiently advanced technology is indistinguishable from magic."
I'm not clear what is meant by "inefficient at energy release". Does that mean that the in the process of energy release, some of the energy is converted into heat? I.e., more energy?
He didn’t hesitate. He said we need to teach children genetic engineering to children in such a way that they could approach it playfully. Only then would we have a chance of developing warm blooded plants which would be essential for colonizing the asteroid belt.
So, if anyone has any ideas for that…!
https://www.youtube.com/watch?v=_yzgPMwshqE
"The first species to emerge from a Noah’s Ark egg will be warm-blooded plants designed to collect energy from sunlight and keep themselves warm in a cold environment. “Plants could be engineered to grow greenhouses the way turtles grow shells” The greenhouse would consist of a thick skin providing thermal insulation, with small windows to admit sunlight. Outside the skin would be an array of simple lenses, focusing sunlight through the windows into the interior. Groups of greenhouses could grow together to form extended habitats for other species of plants and animals. In that way, “We will be the machines getting life to grow all over the universe.”
https://en.m.wikipedia.org/wiki/Leaf_window
https://en.m.wikipedia.org/wiki/Mesembryanthemum_crystallinu...
Here’s the Wikipedia on thermogenic plants. I did not know skunk cabbage can melt snow! I used to have it in my back yard. https://en.wikipedia.org/wiki/Thermogenic_plant
Here’s a paper on the genetics and cellular biology of thermogenesis in skunk cabbage:
https://pubmed.ncbi.nlm.nih.gov/21955303/
Assuming perfect efficiency in capturing whatever sunlight they get, perfect conversion to chemical storage (i.e. sugars, or any other fancy molecule with energy-intensive bonds) and a perfect conversion from that to heat. Would there be enough energy to keep the plant warm? Against a temperature difference of 40ºC+?
So, then again, why would you need to warm yourself if you get a warm sun shower perpetually?
I could imagine a plant that walks along the surface to stay in the sunlight.
Maybe lay down roots all over the asteroid to do the refining and have long tethered leaves always in the sun.
If the leaf stalks can grow at the same rate as the asteroid rotation, just keep growing and wrapping the asteroid until you're left with nicely spooled refined materials.
I don't think a hot blooded plant is practical or necessary, but there is enough energy that it could be possible.
Oxygen plants produce would actually be a lifting gas on Venus so pretty doable. Plenty of sunlight and co2 too.
But I hit a wall with the Mack of water in the atmosphere.
I guess you’d just need to provide your own water?
A while ago I posted about it in Reddit:
https://www.reddit.com/r/ColonizeVenus/comments/ku55zg/float...
Great for power generation though!
That doesn't mean soil for any kind of organism is as hard. There are many of them that don't need all that complexity even on our world that doesn't strongly select for it.
Highly recommended.
https://news.ycombinator.com/newsguidelines.html
Edit: we've already asked you this, and you've unfortunately been doing it repeatedly. Could you please not? If you'd make substantive points thoughtfully, that would be much better.
If you're uncomfortable with people several hundred years ago making decisions about your genetics, why should people several hundred years from now be comfortable with you making decisions about theirs?
[0] https://www.smbc-comics.com/comic/eugenics-is-a-great-idea
Similarly, I do not want the government to have certain powers. But I would happily award myself these powers if I were in charge, to be honest. I would never campaign for that, of course.
This brings me to my argument against eugenics: I think in the current world, it would have horrible effects. It would increase inequality, and create suffering. But that is not a neccessity. In another society, some elements of eugenics could be useful (to be clear: I'm not talking about deciding who can procreate and not, but for example preventing heritable diseases). The thing is, we can't agree on what this better society would look like. I of course believe that would be when I was in charge, but you'd probably disagree :-).
Genetic engineering of offspring is a very different postulate to eugenics though - eugenics is trying to control people's reproductive choice towards an outcome desired by an external party, whereas genetic engineering would be parents trying to get desirable traits for their offspring.
Technically I already did this when I had my first child: me and my wife got genetically tested for possible hereditary overlaps, as well as got as many screenings as were available when the child was developing.
If those tests had shown risk factors, we would have picked IVF or other options to specifically knock out those traits from being passed on. If the technology to select a bunch of genes in my child that favored intelligence, or lower risks of lifestyle disease were available, you bet I would've paid a fair amount of money to get that done too.
Where by "we" I mean the plutocrats who make decisions about how each of us lives now, the Peter Thiels, the Vladimir Putins, the Xis, the Bill Gateses, the Kochs, the Morgans, the Stanleys, the Goldmans and the Sachses.
The other thing that fascinates me is navel oranges. They're delicious, but they're sterile and come with defects (the navel). We're perfectly happy to deal with those defects because the benefits outweigh it. I wonder what defects come from radiation resistant supermen.
Seems we could accomplish the same thing or better with science and genetic engineering.
While likely still restricted to the rich - at least at first - it doesn't have the oppression side to it.
But that thought experiment can go too far too. like elites giving themselves more and creating an even more lopsided world.
When you say 'we could do some eugenics' do you mean the kind of top down, centrally planned by absurd edict shit that we saw from central Europe in the early 20th century that was influenced by North American culture that lingered well into the mid 20th century?[0]
Or do you mean the kind of self empowered eugenics of the late 20th century where women found themselves with newfound means to decide their reproduce destiny for themselves?
What are your thoughts on the burgeoning 21st century development where currently upperclass people are finding themselves in the economically viable position to select and potentially modify embryos for implantation?
How do you think that we as a society should bridge the gap between where we are now with eugenics and where we could be, and how does that tie into where you think we could go as a species either interplanetary or beyond?
[0] https://en.m.wikipedia.org/wiki/Provincial_Training_School
Mostly in Europe and North America, and territories culturally-influenced by them, largely as a side-effect of historical events 80 years ago.
Other parts of the world have different opinions on the matter.
I can't recall the title of an Australian gov't commissioned paper on the subject but this was ultimately the conclusion.
The paper also pointed out that domestic attempts to regulate these acts would ultimately be futile because people were already traveling abroad (specifically Italy) to seek out reproductive/eugenic services that were not legal in Australia.
Vulnerable monocultures; hyper-optimisation for a specific trait (or many breeds each optimised for a different trait); morphology significantly different to the wild form, with fashion preferences leading to fundamental health issues that can only be fixed by altering the fashion (GSD hip dysplasia, pug squashed noses).
People who have to buy RoundUp from Monsanto to keep breathing or to have kids etc.
There is no limit to how bad this could go.
And like pretty much any knowledge or technique, it will be developed and used, and so the only ways to head off the horror outcome is a combination of arbitrary legal declarations to just make some things illegal or at least pointless (not profitable), and open source, putting the same powers in the hands of individuals.
Unfortunately, it lingers well into the 21st one too.
Bug eugenics foundations went through few rounds of rebrandings, and are still there influencing politics.
It seems to me that human potential can be better realised in many ways, and eugenics is the way with probably the worst return on investment.
For a start, we could try giving as many kids as possible in the world a decent crack at doing something important. Obviously this is very difficult and complicated. But then so is eugenics.
It's totally feasible to see 10 point average IQ increases within a couple of generations if we actually did this systematically.
https://youtu.be/YtZqNAI4pBk?t=93
https://news.ycombinator.com/newsguidelines.html
We detached this subthread from https://news.ycombinator.com/item?id=30394933.
We’re running out of excuses. We’re either alone, or we’re effectively alone ie everyone else is forever undetectable. Meaning they’re more primitive, or stuck in some subterranean ocean or something. Either way, we’re the Ancients sci-fi stories ale we ya talk about.
Native tribes could be forgiven for assuming they were alone until explorers and conquistadors arrived.
It’s possible that a civilization millions (or billions) of years ahead of us in biology, energy, philosophy, etc. is just beyond our comprehension at this moment to even know what to look for, where or how.
Plus, we already try to make things hard to find like stealth fighters. Perhaps it’s a good idea for survival in the universe to be difficult to find.
Even if you skip past that to the underlying dark forest idea, it’s an argument based on pure faith with zero evidence to support it. You need an all power malevolent society that works on a time scale of thousands if not millions of years, and then nit only eliminates another society for “reasons”, but also then also perfectly covers up its own existence, because there may be some other bigger bad out there. It’s about as convincing as the unicorn that’s always right behind you, but everyone ignores because unicorns are super dangerous.
They are well worth the read, IMO.
That assumes we would even be able to recognize one if we could see it.
Even if I wanted to be generous, “really big” and “no reason why we would necessarily be able to see any of them” is indistinguishable from my statement of being “effectively alone”.
Also agreeing with one of the comments above about how mind bogglingly massive space is, we've been effectively "listening" to space for only about 100 years, which creates an effective "listening sphere" of 4.188×10E6 light years^3, or 0.000524% of the milkyway's EIGHT TRILLION cubic lightyears in size (even if we could listen to all directions simultaneously, which we can't!)
I mean, we've been listening to the Wow! area for 50 years now, which also hampers the kind of electromagnetic 'sweep' we could possible be doing in the meanwhile.
My overall opinion is that it's just simple not been enough time of listening.
Actually this idea seems quite interesting, it would be cool to do the calculus to figure out our effective "increase" in contact intersection as each consective second, minute, hour, day, and year goes by as we "listen" to space. Infinite overlapping spheres in an infinite 3D space... hmmmm
The reasons why they listen to the hydrogen line is because it’s the most easiest to detect. However, the 50 year timeframe isn’t really a problem. The entire sky has been measured multiple times in this 50 years, and nothing has been found. Unless you believe the signals passed 51 years ago, then the silence is deafening.
Thermodynamics does not play around.
and the dark matter is everywhere (almost, there're galaxies without it) which would mean that most of the universe has intelligent life but then why there's no other signals? something should've leaked/pointed at it
Any sort of Dyson-spherish thing would radiate in infrared, and not be dark at all. A long time ago somebody went looking for these infrared emitters, and found billions (and billions) of them in our galaxy alone. Turns out low-grade infrared-emitting stars and star-like things are more common than dirt. There is no way to tell them apart from a hypothetical Dyson thingy, even if there were any actual reason ever to build one of those. (Which, hint, there isn't.)
"The observational signatures of such “Dyson spheres” include waste-heat from the absorbing sphere, obscured direct star light (resulting in both an apparently underluminous star and potential temporal variations in brightness) and the effects of feedback on the properties of the star from the surrounding sphere."
So there are ways to distinguish probable Dyson spheres from the majority of these natural infrared sources.
You might imagine a playful civilization building one next-system-over to fool planet-bound hicks who actually still believe they are a good idea. The hicks restructure their whole civilization to be able to mount a trip to visit it, and when they arrive find it is all just a mock-up.
EDIT: but I like your idea, sounds like it would be a fun short story!
Dyson was writing at a time before people were thinking about controlled fusion as a way to generate power. Furthermore, he projected not building, but growing a biosphere spread out around a star. The notion of constructing a thing to try to gather and convert all of a star's radiation is a radical corruption of his idea.
Finally, he posited this development in the near term, while humanity remains far short of any capability that could actually be called advanced, with nothing better to hand than genetic engineering and dumb rockets.
Let's presume that the universe is full of Dyson Spheres, and the gravity they produce is what we call "Dark Matter". Well, Dyson Spheres must be built, right? So earlier in time, there would be fewer of them, and later in time there would be more of them.
When we look into the sky, we look back in time. So if this were the case, when we look backwards in time we should see more brightness and less dark matter effects, while closer in time we should see less brightness and more dark matter effects.
We do not see those patterns. Dark matter is consistent over time, as far as we can tell, and brightness from stars remains what we would expect.
If you happened to live in a planetary system without adequate gas giants, you could probably find some way to scoop mass off the surface of your star or capture it from coronal mass ejections, then use fusion to transmute it into the materials you need. Even Sun is 1.90e30 kg, and it's rather small as stars go.
1. "Stellar husbandry". That phrase alone is worth the price of admission.
2. The idea of doing mass spectrometry on a jet of matter coming out of a star to separate it out into streams of hydrogen, deuterium, helium, etc.
3. The idea of creating artificial gas giants as a storage mechanism.
(The list goes on, but 3 is a magic number.)
Isaac Arthur's youtube channel goes into this in some depth (and is generally excellent, IMO). Here's an episode on Dyson Spheres:
https://www.youtube.com/watch?v=HlmKejRSVd8
But there is also the Dyson swarm, which is like a starlink constellation orbiting a star and designed to collect as much energy as possible.
Anyway I don't know the answer to your question, but if we ignore structural problems with a sphere we could imagine a material a few atoms thick, like a giant carbon nanotube structure. Then one wonders how much material there is in Jupiter as an approximation of total matter in the solar system. I will leave the calculation as an exercise to the reader. ;)
Per the Ringworld not being stable, I think the same math applies to the sphere as well as the Ring, so the sphere will need attitude jets to maintain position with respect to the central sun.
Dyson swarms seem drastically easier to construct. We could build one example of that habitat fairly soon!
plenty of material to capture the surface
+ you don't need a sphere, a ring/few rings would be enough
Judging the dynamics of technological societies by those of evolving organisms is a common and extremely misleading trap.
More specifically, anybody sophisticated enough would dismantle their local gas giant and ice planets and convert them directly to energy, and leave the local daystar entirely out of the transaction.
An advanced civilization will exist almost exclusively in the far outer reaches of a solar system, where the daystar provides nothing more than gravitation to keep the Kuiper belt organized. The most valuable resource for this advanced civilization will not be energy, which is cheap, or materials, which are cheaper, but cold. The abundunt cold out in the Kuiper Belt is essential to not being vaporized by the waste heat of the high energy processes more or less advanced civilizations cannot resist indulging in.
agreed that cooling might be something to look for therefore outer reaches are very tempting but then how do you deliver energy there?
I think most people "like" the idea because it's so tangible. But that doesn't make it any more or less likely that it actually exists or makes sense.
1. sidestepping thermodynamic laws - to allow massive energy use without detectable waste heat
and/or
2. sidestepping time lags - so that the system does not need to be bunched as closely together as possible to allow for efficient communication and flows of material
And before you can build a full Sphere you have to build a partial Sphere. Which is where stability will really kill you.
Dyson Swarms might be more practical, but you still have a computability problem because you have an insanely huge number of objects in orbit and you somehow have to keep them from colliding with each other.
Not so much a three body problem as an n body problem. With a built-in light lag delay of (at least) minutes.
I'm not sure if anyone has modelled that, but it would be hilarious if the computing and station-keeping power requirements turned out to be a significant proportion of the available energy,
Wait, what? You can't have a spherical constellation of unconnected stuff that mostly stays in place, that's not how orbits work. You can have a single orbital ring, but a sphere consisting of many circular orbits would have these orbits intersect with very large relative movement. If you're thinking about non-rotating constellation where the gravitational pull is balanced by solar wind, the problem is that they have gravitational interaction with each other and the planets so it's inherently unstable, they would "want to clump up" and as soon as they do, the balance is disrupted as the same mass has less solar pressure and it starts to fall into the sun.
Why would a device that has 1kW/m2 at its disposal at all times, be fundamentally unable to counteract gravitational interactions? We are not talking about planetary gravity wells here but much weaker ones.
There could very well be individual dyson swarms out there and we haven’t seen them or haven’t realized that’s what they are. But building them around every star in the galaxy is something I’ll never understand why it’s taken as a given.
Unless such a civilisation can dump the waste heat as something other than infrared light or send that waste to somewhere other than the visible universe, it’s still extremely visible.
Freeman Dyson never proposed building anything even vaguely like what is called a Dyson Sphere, and was famously irritated at having it attributed to him.
https://www.inverse.com/science/how-many-dyson-spheres-are-i...
I remember some discussion of this point in his autobiography. He wasn't talking about the Star Trek version, but certainly the intercept-all-the-sunlight constructions we're talking about.
All of this is obvious to anyone who does the math.
Obviously the rotation of the star has no effect. But the need to move between habitats precludes substantial differences in orbital plane (look up orbital plane maneuver, these take exceptionally large delta-V), keeping things close to the ecliptic.
Doing the math produces a picture very different from what you imagine.
Even if the cities do cluster in one plane, that doesn't imply the power stations will.
I'm glad you liked Energia though.
I’m always very open to the idea that there could be a lot of physics we don’t understand yet. We could be at 0.1% of an understanding of the basic laws of the universe. I’m not saying I think that is likely or unlikely, but I do think it is possible.
In 1822 the Chappe optical telegraph had been in use since the Revolution, and the electric telegraph was ~20 years away. You'd have had to be singularly unimaginative not to envision an eventual extension to instantaneous voice.
Also the issues of dyson spheres aren't that bad. they could for instance channel the heat loss energy in a narrow beam out of the galactic plane so at least they'd be hard to spot by other galactic observers.
If we don't assume any new physics and / or thermodynamics, then that constrains the discussion a lot. We have two basic ways of generating a lot of power, fission and fusion.
Fission uses fissile materials, which are relatively rare, not just on Earth, but in the Universe at large. There's plenty enough for us at our current energy generation needs, but not nearly enough for a galaxy spanning civilization. That leaves us with fusion.
Fusion reactors, as currently conceived use Helium-3 or something like that. There's enough of that around the solar system to power a civilization for a long time, even though the mass of oddball elements like Helium-3 make up a very tiny fraction of the total mass of the solar system (which is mostly the Sun with a smidgen of Jupiter).
Most of the solar system's mass is plain hydrogen: one proton and one electron.
Is it possible to fuse most / all of this mass in the solar system? Yes. We won't go into the details, but trying to fuse regular hydrogen (regular protons) together is highly impractical outside of the core of a star. Preferably a red dwarf type star which can more completely burn its fuel than our own Sun will, and live a lot longer to boot (a trillion years vs. ~10 billion for the Sun).
So now we're talking about some kind of solar collectors, and if you want to collect _all_ the energy from a star, you want a sphere of some sort. Or a swarm of objects in orbit achieving the same effect.
Hence Dyson sphere / swarm.
For what? What are you doing with it? Not to forget the fact that all energy used eventually turns into heat. All of it (with the exception of electrochemical transformations). You're bringing all of that into Earth you're cooking everybody alive.
How are you bringing that energy from the sphere to (wherever place)?
Putting solar panels on Earth itself works much better. Heck, make a Dyson sphere on Earth (facing outside), that makes more sense.
So in the best case scenario, you are powering computronium, upon which trillions of sophonts live out their digital lives. Hopefully doing some science, or at least playing some interesting games. A vast distributed network.
In the worst case scenario, Blockchain and spam emails.
Either way, people will put that energy to use.
With a Dyson swarm, energy is received on the inside, towards the star, and heat is radiated outward. Lower power systems can run off the heat radiation of the inner swarm similarly. It is all eventually released as very low level heat, but diffused across the entire outer surface of the swarm. No hotspots... because someone would come along and use it.
The Earth would also likely be deconstructed by this time, so don't worry about the biosphere, there won't be any.
One example: powering lasers for light sail ships to colonize other star systems.
Light sails are "theoretically" possible but you don't need that much energy to push something that's feasible to push.
Or better, there's a better source of light radiation: the sun itself. No need for a laser, just use a focusing mirror and you can have 100x more pressure than just from the sun itself.
https://www.planetary.org/articles/lightsail-2-successful-fl...
Light from the Sun isn't coherent, and you can't focus it with mirrors very far away. Lasers have many orders of magnitude less divergence when talking about distances measured in light-years.
To expand on your point, those characteristics become even more important when using the light received to decelerate at your destination, though it is worth noting that there are alternative means of deceleration that don't have the same requirements (eg. electric and magnetic sails).
As the other poster mentioned, harnessing the sun's energy and turning it into a better form suited for light sails is the way to go. Sailing on the solar wind within a star system is a different tech with a different purpose.
I’m missing something here, because even if we decided to build a Dyson swarm of course we are going to start with putting solar on and around Earth because this is where all the stuff we care about is.
That’s just the first step in a journey of a miles miles. (TIL where that quote comes from: https://en.wikipedia.org/wiki/A_journey_of_a_thousand_miles_...).
This seems so obviously it can’t be what you’re taking about though.
Would it not surprise you that fusion in general has been studied extensively by physicists for nearly a century? It takes very high temperatures, pressures and quantum tunneling to get two protons to fuse.
Here's some reading to get you started:
https://courses.lumenlearning.com/physics/chapter/32-5-fusio...
Or read about how the Large Hadron Collider works.
What I'm saying is it's too soon to say what's possible with fusion and what isn't. We don't even have a break even reactor yet. We can even say for certain that we ever will.
I'd give your criticism some consideration if I thought you had even the slightest knowledge of what we're talking about.
Let's talk about the core of the Sun, where p-p fusion takes place. Remember, I said at the top: no new physics.
The core of the Sun is hot, like really, really hot. How hot? 15 million Kelvin. So no solid material ... made of atoms ... can be anywhere close by because it would vaporize. You can talk about active cooling or whatever, and that's not going to help. But let's assume we have some magical material that can deal with that temperature, and keep going.
We're going to skip the pressure that really hot plasma is under, and assume we have terrifically awesome magnetic confinement that can handle that. We don't actually, but let's move on.
The other problem with 15 million K is that all that energy wants to radiate away. Yes, you want to absorb some of that radiation (hard gamma, by the way, very nasty) as part of the energy generation process, but if you let the plasma cool off, the reaction rate drops. "Cool" in this context is relative, at 7 million K, the reaction rate is very close to zero.
The last problem we will talk about today is volume. The above conditions get us a fusion power density of... 276 watts / cubic meter. To have a fusion plant that generates 1GW of power, we'd need to contain a cube 153 meters on a side of 15 million Kelvin plasma.
Oh, wait, that assumes the magnetic containment and everything else requires zero power to run. So we'll have to go bigger, much bigger.
Are you starting to understand the scale of the problem... trying to design a proton - proton fusion reactor?
I am not the arrogant one, I'm just listening to the fusion scientists who have been studying how all this works.
> We don't even have a break even reactor yet. We can even say for certain that we ever will.
And here you are expressing doubt that we'll achieve even the easiest kind of fusion reactor. We have achieved fusion, just to be clear. We can reach the temperatures and pressures to see some reactions.
Assuming civilization does not collapse (climate change, war, etc) we will be able to engineer a fusion reactor that is some kind of practical.
But it won't be proton-proton.
But the scaling issue doesn't go away unless you go with even higher temperatures and pressures.
Doesn't sound like an arrogant person to me...
FYI I understand how magnetic confinement fusion works at a high-level, as a non-scientist.
There's a lot of assumptions you're making here. First that we need hydrogen-hydrogen fusion. Many current reactor designs use deuterium and tritium (nasty stuff tritium.) It doesn't have to be plain hydrogen, it just has to be elements common enough that we won't run out (or that we can breed using neutrons - that gamma radiation you talk about - from the fusion reactor.) Some designs are more exotic with fuel using isotopes of helium, lithium, boron. Second many current reactor designs use a plasma temperature well above 15M K. I've heard of 100M K and that's not an upper limit.
But you're also making assumptions about the volume of a reactor - we don't even know if magnetic confinement fusion will end up being the best design, but if we assume it does - then stronger magnetic fields really decrease the volume required. In fact development of stronger magnets based on high-temperature superconductors may be the biggest breakthrough in fusion research in the last decade - see https://news.mit.edu/2021/MIT-CFS-major-advance-toward-fusio...
> And here you are expressing doubt that we'll achieve even the easiest kind of fusion reactor.
We don't have a break-even reactor yet by the way - we have achieved fusion for short periods of time and by putting in far more energy than could be produced. That milestone is probably still at least a decade away.
My point again is that we don't know enough to be able to say what's possible and what isn't. History is littered with people arrogant enough to say what we can never achieve and humans keep surprising. Sometimes even things that seem impossible - like detecting planets around other stars when the physics of optics is very clear that an optical telescope could never directly image a planet in another solar system. That was wrong on two fronts, one it doesn't account for gravitational lensing, and two it didn't account that we might cheat and detect planets indirectly. And so the arrogant people were wrong again. Don't make that mistake.
I think there are more. Like radiation from evaporating black holes.
Evaporating black holes?
Yes, if you are willing to wait a very, very long time, and have collectors over a large area.
However, if you want to get stuff done before your protons evaporate, you could instead throw matter into a black hole, thus increasing its mass. The radiation given off by the accretion disc is substantial, and can be collected... over a large area.
IIRC, the mass-to-energy efficiency is something like 40%, which is really good.
They are a little difficult to set up however...
That is an interesting prospect, with a very high mass-to-energy efficiency. Of course it requires careful management of inflowing matter. And you can shut if down if needed by stopping the inflow, assuming you have enough stored energy to recreate the micro black hole sometime later.
https://youtu.be/EzZGPCyrpSU
Good channel too.
Not a chance. I disagree 100%. The materials science and orbital mechanics for coordination alone are way beyond our capabilities.
N-body problem instances are never undecidable in the automata-theory sense; you can answer any question about the future trajectory from given initial conditions straightforwardly, if slowly, with interval arithmetic. The question of whether initial conditions exist that evolve to a given result is undecidable, but as with undecidability results in general, we do not need to decide it in order to build a working system, only to prove the optimality of a given program.
You seem to be making up reasons to justify a preselected conclusion without bothering to think about whether they are true or relevant or not, and I wish you would not do that.
You could use a smaller or larger radius, resulting in higher or lower irradiance and higher or lower orbiter density, but we have a lot of experience with different kinds of solar panels at 1 AU, so we know it will work.
No, there's no problem with orbital dynamics, control, computation, communication, or any of that nonsense. 50 years ago those were potentially challenging problems, but not now. Today the only remaining obstacles for a Dyson sphere are manufacturing and politics.
With really thin sails (0.78 g/m^2) they don't even need to orbit, as they can use light pressure to compensate for gravity (what Robert Forward termed a 'statite'). The light they reflect hits other sails on the other side, but this isn't a problem if they are distributed uniformly.
I think the answer may be that most civilizations never need or want to colonize everything in sight. It could also be political: no species gets to the level of being able to build structures like this without breaking up into competing polities. We think about colonizing everything because we’re still in the mode of a creature who evolved on a planet and spread out everywhere.
It’s probably the case that with fusion dyson swarms aren’t used due to the opportunity cost of building them. In 1-200 years we’ll find the idea of surrounding the sun with metal as laughable as there being canals on Mars.
Speculation what form future tech takes should have be broad and uncommitted.
* Given our current knowledge, Dyson Spheres are essentially impossible (just lesser-known point is that unlike planet, full Dyson Sphere or Ring World would not be attracted to the star that it would be built around, so it would have to be guided to move with it - see Larry Niven's Ring World Engineers). * What a civilization would do with all the energy, whether it would want it, etc are other unknowns.
As you say, turning one person's clever idea into a whole research program at the very least neglects other great scifi novels.
It gets converted into other kinds of energy, and eventually becomes waste energy, ending up as low-grade heat. Hence the search for infra-red sources. But the amount of energy that a Dyson sphere absorbs must be equal to the amount of low-grade heat it radiates; so I'd expect a Dyson sphere to be very bright in infra-red - much brighter than brown or red dwarfs.
Such an object should be quite easy to spot.
The signal this would create to an outside observer I think would significantly change the heat signature and periodic changes, depending on our observation angle to the star.
What if the external shield of the sphere would be artificially heated to 4000K or higher ? Completely invisible.