Just an hour ago, I learned about Przybylski's Star. [0]
> Przybylski's observations indicated unusually low amounts of iron and nickel in the star's spectrum, but higher amounts of unusual elements such as strontium, holmium, niobium, scandium, yttrium, caesium, neodymium, praseodymium, thorium, ytterbium, and uranium.
While the explanation is likely some unknown natural process, salting a star with an impossible chemical composition might also be a way for a technological species to create a monument, correct? This seems like it would involve moving less mass around than a Dyson Sphere/Swarm, although it would need a constant feed, if I understand the situation correctly.
Astonishingly, there appears to be no contemporary analysis of this star.
Thanks, I missed the edit window to fix that to read: no contemporary observations,[0] though thanks to you I now realize even that might be not correct.
Given your research on these papers, do you think that this is still an object worthy of closer observation with even more modern tools?
Not an astrophysicist by any stretch of the imagination, but it's definitely an object that's worthy of close research. People are for sure doing that research as well. It takes time to produce serious scientific research though.
How can game theory tell us that hiding from a malicious civilization is a safer choice than exposing ourselves to a benevolent civilization that could rescue us from some danger impossible for us to handle?
My opinion is based on different theories and hypotheses, but the prevalent opinion is that there can't be a benevolent civilization in the first place. And even if there are, they would continue hiding themselves.
Essentially, any alien civilization that survives in the long term is silent and hostile. But especially silent since being hostile can reveal your location.
> but the prevalent opinion is that there can't be a benevolent civilization in the first place.
You'd have to explain why. Logically, the first two civilizations to "team up" would easily handle any single civilization that challenges them. A civilization that happens to beat them would find among its attractive options a Nobunaga Gambit: taking on the vanquished foe's mission of unification (since it worked until it didn't - and the one time it didn't work, there was a terrifyingly good chance that it could have).
"The Dark Forest" as an idea is inextricable from its cultural origins, a China that's rather pessimistic about inter-civilizational contact because of its recent history. That it resonates amidst a zeitgeist of global instability doesn't make it universally correct. Gene Roddenberry's competing vision might seem optimistic, but it's not naive; beneath Starfleet's cheery veneer is the Neo Princess Serenitian realpolitik of, "Peace, or else."
> Logically, the first two civilizations to "team up" would easily handle any single civilization that challenges them.
I don't think saying "logically" and then an unsubstantiated claim constitutes a proof.
If two civilizations team up, whether that makes them stronger, weaker, or equally effective, is not certain IMO.
When two human companies merge, the result is often mistrust, poor communication, poor effectiveness, and sometimes ultimately failure. Sometimes the result of the merger is more effective.
A single, decisive government can run more effective than an indecisive coalition with no clear leader.
I just don't see how a definitive conclusion is possible any way. Surely it would vary case by case.
>When two human companies merge, the result is often mistrust, poor communication, poor effectiveness, and sometimes ultimately failure. Sometimes the result of the merger is more effective.
Those are all important considerations when talking about particular circumstances. Mathematically, however, 2 is greater than 1.
I say "logically" in the sense that, across a broad view of conflicts, the larger combatant usually does the most damage. The reason why is particular to each conflict (more bodies to throw, more brains devoted to tech development, more industrial output, etc.), and when it does not happen, the reason why is also similarly particular. You can also argue whether the circumstances truly yield a "win" (as in asymmetric warfare that ends with the smaller force driving out the larger one on logistical grounds, despite sustaining heavier losses). (Also note that "war" is not "business"; alliances are more important when the outcome of lost battles isn't just lost access to capital, but lost lives).
> Logically, the first two civilizations to "team up" would easily handle any single civilization that challenges them.
This assumes defense is possible. Two loud cooperating civilizations don’t seem like they’d stand much of a chance against a silent, hostile civilization that quietly chucks a few rocks at both homeworlds and any interesting-looking moons, timed to arrive at roughly the same time.
A silent, hostile civilization that applies the astronomical levels of energy to accelerate enough mass to cause an extinction level event at the target in any reasonable amount of time would very likely cease to be a silent civilization. It imagine it would be difficult to hide an energy expenditure of that magnitude; the target may even be capable of deflecting the incoming relativistic payload with one of their own given enough lead time. Also, if there are sufficient loud, cooperating civilizations paying attention to large bursts of energy in their neighborhood, the asshole rock-chucking civilization may find multiple such relativistic payloads heading for their home relatively soon after firing theirs.
Send an agent to an uninhabited star system and launch the rocks from there. Everyone that can see would see the energy expenditures, but they would get very little information other than the knowledge that a stealth based hostile civilization exists. This information would encourage everyone else to be less noisy.
The "stealthy" civilization has ceased to be stealthy, in this case. Launching an attack of any kind defeats the purpose, if anyone but the fully-wiped-out target can see. Your example suggests that a stealthy, hostile civilization isn't possible.
What would an observer see? It’s plausible that they would see an attack from an uninhabited solar system but not be able to find the home location of the attacker.
Ooh, that's the fun part. What (augmented) sense does the observer rely on? On what timescale? How was the attack coordinated? The attack surface of the operation - and the ability to trace it back to its origin - might be wider than you can plan for. "Plausible" is a shaky ground to be on with your civilization in the balance, if you suspect there's even a chance you can be discovered and have chosen to remain as hidden as possible heretofore. Dark Forest doctrine and hostility are incompatible, I think.
If you can achieve faster than light travel (worm holes?) and some sort of immortality (digital? consciousness quantum woo?) then maybe you transcend the worries of physical destruction…
How does this play out with two apex predators...? When you travel in bear-infested woods, the common refrain is to make your presence known -- better to let the other apex predator aware of your existence so you can both give one another a wide berth. Or the Teddy Roosevelt style - walk softly, but carry a big stick.
The theory is that there may be civilizations, or remnants (AIs), that have a vested interest in removing possible competition for resources, or in the case of the AIs, have been instructed to snuff out signs of life for the same reason.
If you are the first one and want to make sure to prevent all future advanced civilizations from evolving, you send out von Neumann probes. You can tell them to build relativistic kill missiles and destroy all planets. No planets = no new civs, probably.
There is no such thing. I think physics and economics dictates that you can't really be advanced enough for interstellar industry and yet backwards enough to have the type of resource scarcity which would compel interstellar resource competition.
If these aliens can not only travel but do resource extraction at interstellar distances, that implies having highly advanced fusion or annihilation reactors.
Minerals are just chemical reaction products, and therefore necessarily cost negligible energy to synthesize compared to interstellar travel. It's easier to just make the minerals you need.
Isotopes are finite in number, and we already know and largely understand all the ones are likely to ever be useful. "Island of Stability" nuclei may or may not be possible beyond that, but even if they're not only possible but also useful, they will almost certainly have halflives short enough that they will also have to be synthesized rather than mined. So, there's no competing over planets either way.
At the lower end of the tech levels where you can have interstellar industry, the only "amazingly high-energy isotope/mineral" is hydrogen fusion fuel. There's nothing in the Earth's crust or core that could be useful for them, because terrestrial planets are made out of spent nuclear detritus. Though maybe they can bring a big fusion candle and just run off with Jupiter, if they forget about their own gas giants and stars.
At the higher end of the tech scale, even hydrogen stops being a resource. Matter annihilation (e.g. via microscopic black holes) means that it doesn't matter what element or chemical your fuel is made out of when you're converting it directly to energy.
I think any resource competition argument for "dark forest" exopolitics really undersells how vast space is, and how abundant resources are. A single Jupiter with basic fusion reactors could easily sustain quadrillions of humans in enormously inefficient utopian living conditions for trillions of years. [1] It's going to need to get a lot more crowded before fighting over minerals is something that any sane interstellar civilization would worry about.
> If these aliens can not only travel but do resource extraction at interstellar distances, that implies having highly advanced fusion or annihilation reactors.
No, it doesn't. You don't know what you don't know. Aliens can have tech based on some rare isotope/mineral/whatever.
> Minerals are just chemical reaction products, and therefore necessarily cost negligible energy to synthesize compared to interstellar travel. It's easier to just make the minerals you need.
Unless these minerals require special rare isotopes or some other material we're not yet aware.
> Isotopes are finite in number, and we already know and largely understand all the ones are likely to ever be useful.
No, we do not. Google "island of stability".
> At the lower end of the tech levels where you can have interstellar industry, the only "amazingly high-energy isotope/mineral" is hydrogen fusion fuel.
That statement isn't a fact. Unless you magically synthesized all possible isotopes and materials. Which you didn't.
> There's nothing in the Earth's crust or core that could be useful for them
But maybe there was, that's the argument.
> Matter annihilation (e.g. via microscopic black holes)
Again, you're talking about known science. Not everything. You don't know what you don't know.
> A single Jupiter with basic fusion reactors could easily sustain quadrillions of humans in enormously inefficient utopian living conditions for trillions of years.
Yes, but that has nothing to do with the argument we're having. It doesn't disprove that there might have been some rare resource (or maybe it's still here, we just didn't get to it).
Properties like the binding energies of molecules and nuclei are a direct and well-understood consequence of the laws of physics. Materials in the real world aren't like Star Trek, where dilithium and the omega molecule can be treated as an infinite energy source because the name sounds cool. In order for a material to be an energy source, that energy has to come from somewhere.
You can only put so much strain on a chemical bond before the electrons decide to stop sticking together anymore. You can only get as much energy out as the mass change from splitting an atom. You can only store as much energy in a heavy nucleus as was originally put into it by the supernova that created it. Anything else would violate basic laws of physics, to such a degree that everything in our universe would presumably immediately cease to exist.
> No, we do not. Google "island of stability".
I already addressed the hypothetical island of stability in the sentence immediately after the one you quoted. The term is relative. They are expected to have longer halflives than the instantly decaying superheavies like ununoctium, but even the longer predictions of their decay properties have them disappearing far too quickly to be mined as minerals.
I'll add now that there's also no reason to believe that island of stability substances, if they even exist, will have any more particularly useful or powerful properties than any other heavy metal. When was the last time you needed to use Mendelevium for something?
> Yes, but that has nothing to do with the argument we're having. It doesn't disprove that there might have been some rare resource (or maybe it's still here, we just didn't get to it).
It disproves the idea that there might be some useful resource which you would want to go conquering for. The resources available in any star system are already more than any conceivable civilization could ever use.
The other side of this is the difficulty of interstellar travel. Reaching relativistic speeds implies turning a significant fraction of your vehicle's mass into energy. With the ability to create and manipulate such power densities, you're better off just synthesizing whatever you need.
> No, it doesn't. You don't know what you don't know.
> But maybe there was, that's the argument.
> Again, you're talking about known science. Not everything. You don't know what you don't know.
If the argument for suggesting a complete break from the known laws of physics can be summarized as "You don't know what you don't know", then you may as well argue that the universe is secretly controlled by a giant space cat which will reward us with salmon if we all shine laser pointers in our retinas every third Thursday.
"Maybe there was" is not actually an argument, in the sense that there is neither anything specifically substantiating it which can be examined, nor any falsifiable conditions which may disprove it.
All your arguments are basically "we already know all of physics, there's nothing new to learn". Which is just wrong.
And then you engage in obvious logical fallacies like talking about mendelevium, as if it's exactly the same as hypothetical stable isotopes from the island of stability. You have no idea what you're talking about, you have not produced those isotopes, no human did.
And then you engaged in completely dishonest straw man with the space cat. I never claimed that there are such isotopes or other used yet unknown natural materials, I just suggested that there may have been some.
Considering how dishonest you are, I won't respond any more.
My argument is that based on everything which we do already know, it is unlikely that any material with the physical and economic properties like what you are suggesting can exist, and any "suggestion" that such a material does exist is completely arbitrary. Russell's teapot, and all that. There's plenty new to learn, but it'll probably be closer to strangelets and dark matter in exotic conditions than "baryonic rocks but amazingly shiny".
The entire point of "science" is that you can and should make reasonable predictions based on past observations. E.G. Mendelevium. Calling that a "obvious logical fallacy" is… Disturbing, frankly.
You know, I've yet to see you make a single point that's based on anything more than "Maybe", "No, it doesn't", or "How dishonest you are". Lots of rhetoric. Not much else.
It is your choice to interpret disagreement and contradictory information as "dishonest". Have fun with that.
Offense is easier than defense. How do you know some other civilization isn't going to, say, get angry at their own decline and unleash destructive Von Neumann machines on the galaxy?
By the time you know whether or not another civilization is hostile, it’s probably too late. “Interstellar war” sounds like a long dragged-out set of engagements when it’s more likely that one random day without warning your planet intersects a sizable chunk of tungsten traveling at 0.9c.
Another reason not to confine your civilisation to one planet, or to planets generally.
Much harder to wipe out a civilisation that's dispersed among hundreds or thousands of smaller space colonies. Especially if many of those colonies are hidden in an asteroid belt of millions of rocks.
Whatever scattered remnants that are left of humanity hanging out in the asteroid belt are going to have a hell of a time finding food to eat or oxygen to breathe.
Resources. Perhaps their star will soon (on a cosmic timescale) consume their planet and they're looking for another solar system to inhabit. Labor for their Dyson sphere. Who knows. But, if something goes out of their way to make contact, odds are it won't be a friendly hello.
> If you are a civ who is able to do it, surely you can grow whatever food you need at home and have advanced AI/robotics that can provide labour.
That's about as reasonable an argument as "if you drive a Tesla, surely you can afford to donate to my cause". Maybe they are way over-invested in their FTL technology and really have no choice but to look for external labour. Maybe they painted themselves into a corner with the FTL tech that can get them here, but they need our labour to enable their drives to restart for the trip back. Or maybe whatever reasoning they have is so _alien_ to us that we simply can not comprehend it.
Yes, it is possible that whatever FTL tech they are using will work with a living creature but not with some machine. Maybe they just encode human DNA to clone for slaves because their culture does not allow them to use their own DNA for slaves, and DNA is easy to send over their FTL tech.
When discussing aliens you have to consider that their reasoning, their culture, their motivations, their technology, their customs, their values are all _alien_ to us. You have to be open minded, for every excuse we can come up with for "why not" there are infinite explanations for "why so".
The thing is that culture, motivations, and technology are all shaped by constraints imposed by the laws of physics, which (by definition) can generally be presumed to be universal. Having plausible explanations for "why so" doesn't change the fact that doing so would likely be so inefficient that it would place their entire culture at a significant disadvantage.
Yet on a cultural level, I think the "food/slaves" narratives of alien invasion are actually failing to be open-minded enough. Mechanical labor and physical nutrition are the kinds of things that our newly industrialized post-colonial societies worry about. It's not actually a particularly "alien" idea. Thinking a much more technologically advanced society would come to Earth for the same reasons comes across to me as projecting our own anxieties and sins.
> If the rabbit is injured, making noise and hoping for humans to help is a fools errand as the fox is more likely to hear and eat the rabbit.
> This is engrained in our evolution.
Literally the exact opposite?
> Recent research has also shown that the acoustic properties of human screams can be reliably detected within noisy environments, something presumably indicative of having evolved in noisy environments, such as dense forests, where there is a strong adaptive pressure to reliably signal danger (Nandwana et al., 2015).
> Rabbit Basic Science: The only vocal sounds that are made are a loud high-pitched scream of terror or a range of growls and hums that denote pleasure or defence. Apprehensive or frightened rabbits will thump the ground with their hind feet. The loud thumping sounds acts as an alarm signal to other rabbits in the vicinity.
> Screaming among rabbits indicates alarm associated with fear, pain, and psychological distress. Your rabbit may scream because it is scared of being attacked or dying. Rabbits also scream when they’re in excruciating pain, or when they’re having a seizure. …it is a sign of extreme pain, terror, or calling out for help.
> Lima beans release volatile chemical signals that are received by nearby plants of the same species when infested with spider mites. This 'message' allows the recipients to prepare themselves by activating defense genes, making them less vulnerable to attack, and also attracting another mite species that is a predator of spider mites (indirect defence).
IMO "Dark Forest Theory"— The idea that (1) nobody would ever help anyone else and (2) nobody could ever understand anyone else because (3) we're all dumb forest animals capable of nothing higher than survival, so we may as well (a) hide and (b) kill anyone that tries to talk to us— That probably says more about the people arguing for it, or about our own providence, than it does about any probable intestellar ecology.
> Humans become a rabbit, the malicious species a fox, the benevolent species humans.
In fact, if anything, using humans as the example of a benevolent society points out the absurdity of assuming that more technologically advanced polities must necessarily be malicious.
Killers don't prosper in civilized societies. And technologically advanced societies ruled by killers don't last long.
Out of curiosity: is your statement based mainly on the Liu Cixin series? Or is there some more depth to it? If so, could you give some pointer to the more in-depth analysis of this hypothesis?
There is lots of work done on it in the SETI field. The dark forest theory doesn’t hold up under game theoretic analysis (hiding is not the optimal strategy, nor is predation), and is pretty resounding rejected.
Not sure what the best resource would be for an outsider to delve into this field though.
I imagine it depends on whether interstellar travel is practical. If intelligent species come to the conclusion that they’re forever isolated, a monument seems a rational, almost inevitable choice.
And how do you know you're forever isolated? There are things you don't know that you don't know. No rational species would ever build a monument IMO, and again, game theory supports this so far.
> Game theory reveals that the best thing an intelligent species can do is to hide. (The dark forest hypothesis)
Under certain conditions and with certain assumptions. Under other conditions and with other assumptions, the best thing for a species to do is be altruistic.
Does being the destroyer in the dark forest scenario not reveal yourself to other destroyers?
Also while I'm sure a relativistic kill vehicle could neutralize a planet, will it also get all the populated moons/orbitals in the system? What if the target species is already multi-system?
Accelerating a rock to intercept a separate star system doesn’t need to generate any particularly noticeable emissions.
If it was intercepted someone could work backward from its trajectory and determine an origin, but the odds of noticing a cold, small, dark rock at relativistic speeds early enough to do anything about it seems slim.
It is a nice scheme, but what if your target is not bound to gravity wells anymore and the most of its economy is artificial structures orbiting its sun?
You will hit some ancient rocks orbiting the star, and even if people there dont need them anymore they are bound to become curious of the origin of your missiles.
Sending a relativistic chunk of tungsten is something we could accomplish at essentially current technology levels. Hell we could send a hundred of them. It’d be expensive and it would take awhile to get there but we could do it in a decade given sufficient motivation.
If caveman-level weaponry is sufficient to take out anyone not well on their way to becoming a Type II civilization, I’m betting on the cavemen.
I don't think we could do this at all, even theoretically.
If we took all the proven petroleum reserves in the world, and magically converted them into kinetic energy with 100% efficiency— With zero overhead for transportation, launch, agriculture, or obeying conservation of momentum— That still wouldn't be enough to launch even a single planet killer. At most you could crater a small country, but not kill a civilization:
So let's say you do nuclear pulse propulsion like Project Orion. You've still got Tsiolkovsky's rocket equation to deal with. Assuming a speculative fusion bomb ISP of 75,000s, you would need a rocket with… over 50 orders of magnitude more mass than the entire observable universe, in order to accelerate a single proton to 0.9c:
Light sails will be huge, obvious/visible, and slow. Beamed power will run into issues with diffraction.
In fact, reaching 0.9c while you're still in the solar system plainly implies maintaining multiple hundreds of g's of acceleration over many dozen astronomical units of distance. That doesn't seem feasible at all. It's wildly beyond not only our best existing ion drives, but probably also any remotely feasible existing concept for space propulsion.
This probably isn't true: we don't even have enough conventional weapons to destroy our own planet, and we've been optimizing that for centuries. A relativistic missile is a conventional weapon scaled up.
We couldn't accomplish this. Theoretically speaking, yes we could, but "theoretocally" means "ignoring the half of the reality". We can't even travel to Moon now practically.
To send a chunk of tungsten at a relativistic velocity would mean an effort for trillions of dollars. Don't forget that it is not enough to just get a chunk of tungsten moving, you want it to hit a moving target, and you'd better add some thrusters to it and a guidance system. Is there anyone willing to pay for that?
Any civilization will need to concentrate a lot of efforts to fire a chunk of tungsten, but why might it do it? There are better ways to utilize that effort. Maybe it is a rational thing to go aggressive nevertheless, but the benefits will be in a far future while politicians needs to justify spending now. People and societies are not rational. There is no real examples of rational agents, but people still insist on treating rational agents as something real. Theoretically speaking AGI might become a rational agent, but I doubt it from a practical standpoint: AGI will be limited by a computational power and by its abilities to gather data. So it will use heuristics, and it will be not rational. It can be closer to a platonic ideal of a rational agent then human, but even that is not free of doubt. People surpisingly well do with all their heuristics and when they appear irrational it is mostly due to inability of observers to understand the real motivation of people.
You need a much more advanced civilization to be as aggressive. A civilization that can do it by spending maybe 0.1% GDP for 10 years. At least looking at humanity, I'd say that any cost higher than that will not work definitely.
Such unprovoked and costly agression having no observable results easily could end a lot of political careers.
Theoretically speaking we can ignore all these difficulties and start with the assumption that it is possible to concentrate 100% GDP on a one task for years or even decades. Practically it is impossible.
Maybe another civilization will have another structure and will be able to concentrate efforts on a larger scale then humanity? Maybe. But could you imagine such a hypothetical civilization and estimate chances of it to get to a sufficiently advanced level? I cant neither. So while I keep in mind this theoretical dreams of rational civilization purging each other, I do not assign any credibility to them. I keep myself in an uncertain state, the best state to have an open mind, to be ready to absorb any evidence or reasoning.
They might notice the bits of interstellar dust that at the upper size range hit at 0.99c with kinetic energy on the order of magnitude of tactical nuclear weapons yield. This also makes targeting interesting without thrusters and fuel to correct their probably regularly perturbed trajectories. Those cold, small, dark rocks may not be quite so cold or dark if they're going to actually try to hit their targets.
People seem very confused by this so let me try and spell it out.
For the sake of argument let’s say we become aware of another intelligent civilization on a rocky body orbiting Proxima Centauri. They are, virtually by definition, apex predators on their homeworld. We cannot know their intentions should they learn about us.
Meanwhile, it is trivial for us to end their civilization. If we decided to, with more or less today’s technology, we could accelerate a chunk of tungsten to comical speeds and obliterate their homeworld. It would cost a fortune and it would take awhile, but we could do it. Certainly it would be orders of magnitude easier than getting humans there, setting up any sort of interstellar trade, or working to understand each other’s language and culture. And nobody at the receiving end would be the wiser until their planet essentially ceased to exist one day.
I’m not saying we want to. But we could. And importantly, they could do the same to us.
Do we:
1. Loudly announce ourselves, gambling our entire civilization that they aren’t aggressive, paranoid, misunderstand us at some point and take grave offense, realize we have a nicer planet than they do, or find some other reason to become openly hostile.
2. Shut the fuck up and hope they don’t catch our leaked radio signature from before we knew any better.
3. Strike first, just to be safe. Better us than them.
If we think that any other civilization might decide to open door number three, the calculus tilts sharply in favor of doing it first ourselves. Or at the very least going with the second option and investing a hell of a lot of money into figuring out how to detect, intercept, and redirect relativistic kill vehicles.
It doesn’t even have to be the Centauris in this scenario who are evil or paranoid. They could be just as hopelessly naïve as us and happily engage in a mutually beneficial back-and-forth. Meanwhile the Sirians (who have been quietly observing from the sidelines) one day fire off a pair of surprise care packages to the both of us, before we can get big enough to potentially threaten them and their way of life.
More or less today’s technology could not accelerate tungsten to speeds that would obliterate a planet.
And you say it’s trivial? Who told you this?
Just run some calculations it doesn’t make sense.
(just one example, 10,000lbs of tungsten hitting the earth at 99% of light speed would not destroy it)
——
it is trivial for us to end their civilization. If we decided to, with more or less today’s technology, we could accelerate a chunk of tungsten to comical speeds and obliterate their homeworld. It would cost a fortune and it would take awhile, but we could do it.
Not to mention the difficulty of hitting a planet-sized target at 99% of the speed of light from 5 light-years away. I'm pretty sure this would be vastly more difficult than anything we've ever accomplished as a species.
Plus with those same resources you could probably build a solar-system-sized passive interferometric radar swarm, and get decent warning time on any relativistic launches.
0.99c of blueshift coming from a specific star's direction? Weird. Shoot a couple relatively slow BBs at it, and the projectile will vaporize itself around the Kuiper Belt.
Poor guys. They've now announced to the universe that they're an aggressive threat to all life around them…
With our current technology, it isn't possible for us to accelerate any amount of tungsten to relativistic speeds except for a few atoms in particle accelerator. The rocket equation means needs ludicrous amounts of fuel to reach relativistic speeds.
This includes near-term technology like fusion reactors. You could take Jupiter along for fuel but still not reaching 99% of light speed. For stationary launchers, they would be super long or require enormous amounts of energy. Giant arrays of lasers aren't "possible with current technology".
Relativistic projectiles probably requires antimatter. Which are pretty far beyond our technology. There is big question is antimatter rockets are possible, they require producing and containing a lot of antimatter. Although, it instead of accelerating super fast, it is probably easier to send the antimatter.
That's like 0.003X of a Chicxulub impacter. Or around 1X the geologically very recent eruption of Mount Toba.
The ecosphere will be fine. You'll probably vaporize a small patch of ocean, and they'll get colorful sunsets for a couple days. But that's about it.
By contrast, assuming "more or less today's technology", we're now out of petroleum reserves because we used them all in our magic instant-acceleration kinetic-energy-converter.
At the link below you can see simulations at 99.9% light speed. An entire Egyptian pyramid, hitting Earth at this 10x higher speed, might kill off life, but it’s still not obliterating the planet.
We are not capable of accelerating any macroscopic object to .999C. Let alone a huge piece of tungsten, which still wouldn’t be powerful enough.
In this hypothetical scenario, we wouldn't know if they have known of our existence for a long time, and maybe even taken precautions like installing some proxy killer probes in case we had a stupid crazy idea like trying to launch a genocidal relativistic missile against them.
So, why would we go so blindly for option 3 and risk it all by being the first ones to defect in an interstellar prisoner's dilemma? Especially if we have good reasons to suspect that they've known about us for long and have remained neutral so far. After all, Proxima Centauri is quite close, and our atmosphere gives ample signals of there being life here. And we haven't been particularly quiet either.
I haven't delved deep into this, so there might be some much more tight logic to it. But my first impression is that the dark forest hypothesis seems a bit forced; sort of constructed backwards in order to explain a cool idea (that space is full of civilizations but everyone is quiet).
For example, one of the assumptions it makes is that obliterating another space-faring civilization is easy. And, at the same time, that we (and everyone) have very little information of other civilizations. I don't see how these two assumptions can hold at the same time.
These scenarios are so funny because they’re totally focused on threats and destruction as the key assumptions, and then they invariably conclude “so we should destroy them”.
And it’s just like, that’s such a colonizer mentality, trying to game out a completely unknown society and immediately focusing on threats, technology, and destruction.
I wonder, what are they like? What could we learn from them? Why are we assuming all beings are violent like us? Does it really make sense to immediately obliterate a culture you’ve never even seen? I seriously doubt it. You could send probes, spies, and try to covertly learn about them. You could send envoys, without revealing your origin, and try to gain knowledge from first contact. You may learn there is no threat, and a great deal to be discovered.
What if they had medicine which could cure every disease? Energy generators which could save our planet? What if they were simply peaceful beings with a rich beautiful history, and no desire or capacity to harm us?
The threat/destruction paradigm feels so simplistic, impoverished, and brutal.
> I wonder, what are they like? What could we learn from them?
Of course I wonder these same things. But when the consequences of becoming known to the wrong civilization are inevitable destruction, what are your alternatives?
We very nearly killed ourselves (we still might!) with nuclear weapons because we thought the other side might shoot first. This is that taken to an even further extreme: we won’t even know if we’ve been shot at until it’s far too late to do anything about it. We likely wouldn’t ever even know who sent the damn thing in the first place.
The balance of things is that silent civilizations with caveman-level technology are more than capable of wiping out noisy and naïve technologically-advanced civilizations.
You can wonder all you like about who and what these beings are and what wonders they must know of, and absolutely none of that will matter when a tungsten rod turns the planet into a fireball because you made the mistake of sending up a signal flare without having any idea that it was safe to do so.
One in a thousand civilizations could be paranoid enough to sterilize other spacefaring civilizations and it would be reason enough to be very, very quiet.
> when the consequences of becoming known to the wrong civilization are inevitable destruction
This is the presupposition that seems entirely baseless to me. An explanation has been constructed that comes to this as the only conclusion, but the assumptions in the explanation seem themselves to come from nothing. I think this is what often called "projection". Human beings are a violent creature that destroys others, so we assume these alien creatures must be. But they are aliens. We presently know nothing about aliens. My view is that we should interrogate the assumptions that lead us to your brutal conclusion. Projection of our own fears is insufficient to make the right choice.
Another question to reflect on: Why do you not destroy every person you come in contact with? They could likely kill you if they tried. But more so than legal consequences, you simply feel no desire to do so. There are reasons for your feeling that way.
If you believe in dark forest, it's not one in a thousand, even benevolent civilizations have a reason to genocide you, because you would shoot them indiscriminately.
> It would cost a fortune and it would take awhile, but we could do it. Certainly it would be orders of magnitude easier than getting humans there, setting up any sort of interstellar trade, or working to understand each other’s language and culture. And nobody at the receiving end would be the wiser until their planet essentially ceased to exist one day.
Many of these arguments seem to work equally well for France nuking Britain.
I am also skeptical of any overly pessimistic alien interaction theories, but I don't think this analogy applies here. We already have open communication channels and centuries of trust between the British and French, and we certainly did pillage each other before we figured out how to speak to each other.
> Meanwhile, it is trivial for us to end their civilization. If we decided to, with more or less today’s technology, we could accelerate a chunk of tungsten to comical speeds and obliterate their homeworld.
We wipe out their planets, then the 99% of their civilisation that isn't living on planets wipes out our planets. Now we have two very angry civilisations (without planets) in a protracted interstellar war. Great.
Specify a current technology that could accelerate to 99% light speed. Heck, specify future technology that we could conceivably build. Now, what is the exhaust velocity? What is the mass ratio for the starship? How big is that compared to mass of the entire solar system?
How is that energy expenditure going to be not noticeable to aliens?
4. If they didn't notice anything, we can wait more and send them a spy probe to learn their culture. If they are mad foresters, we might genocide them, but if they aren't, it's not more dangerous than having France with nuclear weapons. Under this strategy only foresters get what they want :)
I've never really understood the dark forest thing. Being an intelligent species or not doesn't change whether your planet has useful resources. And if you're a naive species yapping on all frequencies, you're clearly not a threat. So... why would another civilization go to all the trouble of eliminating you?
The idea is that, because of the risk of a technological explosion, any sentient species is a threat.
I don’t really buy the idea though - cooperation has been the strongest strength of humanity and is one of our greatest evolutionary edges. Why wouldn’t that apply on the interstellar scale too?
Shoot first and ask questions later, if anything shooting first is safer (civilizational risk) on the chance they are thinking the same. On the flip side, an alien civilization sees our request to cooperate, they can accept or they can destroy us, to them we could be lying or go back on our word and destroy them.
I see some criticism of dark forest theory in here, but keeping quite and shooting first are the least risky options when the inentions or capabilities of another civilization are unknown and making assumptions about the other sides friendliness could lead to eithers extinction.
Reasonable to assume that if I have a weapon that can destroy a civilization, others may have it too. Assuming also they have the similar risk calculus, it leans towards hiding and then nuking when either gets afraid enough. You can't do much but hope the other side is not more advance that you and can mitigate the attack.
It seems like a big stretch to assume aliens are going to share ideas of liberal democracy like fairness/cooperation etc (which are fairly recent) when there are groups of humans who do not
Then we are probably dead anyway, the onus would have been on them to contact us as they are probably several centuries more advanced. In that case its like going with a tank to an island population that still uses bows and arrows
You do realise that comment supports strongly the dark forest theory right? The best thing do do before you have a tank is to shut up and hide. Of course you don't pick fights when you could get squashed
Implied was that the actions to take if we had full info are obvious. If their capabilities are known you would not have to resort to "shoot first, ask later"...
But the dark forest theory suggests when you have an arrow, you should shoot others, because they can have an arrow too. This strategy can go wrong if they have a tank. And if you systematically shoot everyone, you're systematically looking for a tank.
So far, yes, but not intentionally. Any electromagnetic wave we emit becomes noise. We're still ants compared to what alien civilization can be theoretically. But this does not mean we'll always stay this way.
I'm a supporter of making humans detectable in any way illegal.
> salting a star with an impossible chemical composition might also be a way for a technological species to create a monument, correct?
It's an impossible composition from a nuclear physics point of view, since the star shouldn't be producing these atoms, and they can't be part of the initial makeup of the star since they're unstable elements and would long be gone by now. The most likely explanation is still that something randomly collided with the star.
If it's a monument, then it certainly is the right one to send a (very vague) message far into the future, "we were here".
> This seems like it would involve moving less mass around than a Dyson Sphere/Swarm
It's a bit weird to compare two endeavors we haven't even tried yet, but making a Dyson swarm seems vastly easier than this. To pull off the salting of a star, you'd need to constantly manufacture vast amounts of exotic radioactive materials. A Dyson swarm may be massive (although there would be very light-weight ones you could build if the only function was to be a monument), but it's "just" a lot of solid bodies orbiting a star. A star salter, on the other hand, would require way more complex engineering.
Yeah, you are correct. My brain is a bad model lately, since Advanced Neuro Lyme Disease. I synthesized the information from those podcasts + google poorly. This is depressing.
There are plenty of possible signatures (though uncertain) of actinides in there as well, some of those -could- have short lifetimes so not that far off.
Thanks, but I should have caught that. The good news is now that my brain is not as good at the details [0], I may finally be a good fit for a management role (:
[0] It's actually getting a lot better, I hit brain-rock-bottom a year ago. I literally could not think at all. Damn those ticks.
Thanks. The crazy thing is that I never noticed any bites, that's how it got so advanced. I only know that's what it was for a fact due to blood tests, which I only got after I started to lose my freaking eyesight.
After recovery, my brother and I laughed about this once he pointed out that I do in-fact live in a village called Deer Mountain (loose translation.) Like what does one expect? They are deer ticks, after all.
Also, I love opossums! I grew up with them in The States, but we don't seem to have them here in Europe.
Thanks. To answer your question: well, I kept sleeping too much at first. But I live a very sequestered life lately, so I had little frame of reference. Looking back, one of the most surreal things is that I recall telling my friends on the phone that I was having a hard time telling dreams from reality. It wasn't until after the diagnosis that I looked this up and found out that this was a symptom of Advanced Neurological Lyme Disease. WTF.
Then I got joint pain, then the really weird eyesight loss, in short order.
What I would recommend is getting the antibody tests if you have any concern. I am in the EU, so that was very cheap w/o insurance. I believe in The States they recommend prophylactic Doxycycline, at any concern, instead of testing because testing $.
Prophylactic Doxycycline is a couple pills. Since I missed that, Advanced Neuro Lyme was 30 days of 2 high-dose pills a day. In the USA, they require IV antibiotics for Advanced Neuro.
This dumb crap changed my life, so again I would ask, or demand testing for ELISA. If that comes back positive, then there will be a different "Western blot" confirmation blood test. If they say no, then find a local clinic and pay for the ELISA yourself.
Yes please! It's less than 300M light-years away! It's crazy that we haven't done this from the ground recently. One of the issues is that it's in the Southern sky.
According to Prof. David Kipping, ~"The guys who are into these weird things have somehow never heard about this star, it just got lost in the shuffle."
Also, Kipping mentioned that some of the research was Czech-based, and not in English, which may have also been a factor.
My very uneducated guess was that two planet-like objects smashed, and there is some cloud around the star which gave those weird spectrographs?
> My very uneducated guess was that two planet-like objects smashed, and there is some cloud around the star which gave those weird spectrographs?
Another guess: it got close to a neutron star merger, and was showered with high atomic number debris. Heavy elements can be produced in mergers of such stars.
Something which might align with this guess is that this type of star apparently has an extremely strong magnetic field which could trap, and excite those particles?
However, assuming that it's not misidentification, would it be fair to say that new physics would have to be discovered to explain things like Americium and Einsteinium?
> One such theory is that the star contains some long-lived nuclides from the island of stability (such as 298Fl or 304Ubn) and that the observed short-lived actinides are the daughters of these progenitors, occurring in secular equilibrium with their parents.
One could also imagine a huge rotating, sun-orbiting ring with alternating openings that blinks a out message to astronomical observers, perhaps in some form of Morse code or binary.
That is what I always used to imagine as our monument, maybe the Fibonacci sequence via orbiting star shades. Or maybe that's too natural, maybe a binary sequence via orbiting star shades.
However, while I ain't no city-slickin' Kardashev Type II orbital mechanic, all those star shades might not be in a stable orbit over hundreds of millions of years. They might require some propulsion for station keeping. That sounds hard for anyone, across those time scales, especially as the star grows.
It might be "easier" for longevity, to terraform a Mercury type planet with unnatural chemicals, then smash a large off-plane comet into it, to create a band of non-star weird chemicals which would fall into the star and should last for millions of years, giving it a one-in-a-billion spectrograph?
edit: Come to think about it a bit more, I would argue that the latter solution is entirely within our technological grasp nearly today, as a pre-Kardashev scale civilization.
Not that I think speculation is bad, but the concept of intelligences expanding by building space structures so immense needs some push-back:
Is there enough time in the lifetime of a star to build and use those structures?
Are there plausible social arrangements stable enough to last the duration of such a project?
Are there intelligent beings with a drive to limitlessly expand their population?
A lot of the ideas behind hypothesizing swarms of space structures, each orders of magnitude more massive than Earth, feels very 1970s population/energy-crisis inspired.
> Is there enough time in the lifetime of a star to build and use those structures?
Easily. Sci-fi has misconstrued what a Dyson Sphere is to the point where the preferred nomenclature is "Dyson Swarm". A Dyson Sphere was never a rigid shell around a star. Such a thing isn't possible with any known or theorized material. And it makes no sense even if you could.
So a Dyson Swarm around our Sun would be approximately a billion O'Neil Cylinders (orbitals 2-4 miles in diameter and 10-20 miles long). You don't have to build them all at once. Build them as you need them. The more you build the more industrial capacity you have. They can all be built independently too.
I imagine it would take less than 10 years to build one once you have the capability.
> Are there intelligent beings with a drive to limitlessly expand their population?
Population is only one concern. A more driving force may well be the desire for energy and raw materials. Raw materials, and in fact most problems, can be reduced to being an energy problem. Some things will require a truly mind-boggling amount of energy eg interstellar travel.
Our Sun won't live forever. It's estimated to go into a red giant phase in 4-5 billion years, that will end up swallowing the Earth most likely. Long before then, life won't be able to exist on Earth as the Sun's solar output is increasing by about 10% every billion years. Earth as it stands now to us as we are now will be uninhabitable in ~1.6 billion years.
So to be truly long-lived we're going to have to do something about that. There are lots of options. Those include reducing the energy that hits the Earth, moving the Earth or moving our species to a different system. The last one is particularly attractive because white or red dwarves will likely exist for trillions of years. Every one of these options requires a vast amount of energy.
> ... swarms of space structures, each orders of magnitude more massive than Earth
> Are there intelligent beings with a drive to limitlessly expand their population?
Since the development of contraceptives we are now selecting hard for any and all traits associated with intentional reproduction or the desire for children.
A few thousand years of this and the only thing left will be people who really want kids, or who are prone to adopt beliefs or attitudes that lead them to want kids.
Maybe this is how you get a Dyson swarm.
I’m not even including potential AI “life” in this picture.
> A few thousand years of this and the only thing left will be people who really want kids
It would take less than a hundred years to create the first baby from scratch without human intervention. From there, the possibilities are endless. China seems like a probable candidate that lacks human rights controls and has enough biotech to build world’s first baby factory, but even if only North Korea has the tech and political will initially, the pressure on the depopulating countries would either legalize these or at least relax immigration to the extent necessary to benefit from them.
The problem with this theory is that the family is the most important human institution and all of human evolutionary history has occurred in the context of this fact. So if you think you can just make babies without families, well… just go see how things went whenever communists have tried to replace the family with the state.
> A few thousand years of this and the only thing left will be people who really want kids, or who are prone to adopt beliefs or attitudes that lead them to want kids.
I don't think this follows. If this general line of thought were true, there would be no gay men, few gay women, and almost no infertile people in general.
It is probably why these traits are not in the majority.
Humans have complex social behaviors and are subject to a lot of higher order group selection. There can be lots of people who don’t directly participate in reproduction who indirectly do so. Community and economy are central to what made us the top large organism on Earth. We are very complex social creatures, probably the most on this planet.
But as long as humans reproduce as they do with such high overhead, the mainstream of our population is going to be selected so that the center is aligned with that.
I wondered if you are responding to the risk of population collapse / aging population, and feel resentful towards reproductive rights believers because you feel they are to blame. It seems you're hoping that reproductive rights supporters will ironically self inflict an eugenics program upon themselves, leaving only virtuous breeders.
In humans, fast breeders may be likened to r-selectors that select for quantity of offspring. They tend to be poor and uneducated and select for quantity despite constrained resources and the developmental setbacks that will cause their offspring. So fast breeding is not necessarily an overall selection advantage.
Otoh, reproductive rights believers (which are like K-selectors) tend to have higher incomes and education levels, and select for low offspring count and high investment in individual offspring. So while they may have fewer children, they will have more resources to give to their children, and their traits may enjoy selection because of this higher fitness in the offspring.
In the end, you should expect to see an equilibrium with both fast and slow reproducers - since both are in competition, both have some weaknesses and advantages, and neither is dominant. There may be a shift happening one direction or another. But it can't be a winner take all outcome, because there are too many factors in tension.
For example, the upper class are likely to remain K-selectors, because they draw their fitness from their wealth, not their offspring count. In other words, they can afford it. That won't change without social collapse or revolution.
You pretty solidly misunderstood what I was saying, which is probably my fault for not being clear.
I said up top that I think the right wing panic over this is BS. Humans are definitely K-selected, and I am not against reproductive rights.
What I was really arguing is that reproductive rights could in fact increase intentional human fertility if there are any levers evolution can pull to do this, and that a temporary dip in fertility caused by reproductive self-control might be followed by a large increase if this occurs. It's not something I'm hoping for or not hoping for, just an observation about how systems might respond to constraints.
It's not my idea really. I'm kinda parroting something I read once about evolution:
"You don't understand evolution until you understand how contraception could cause overpopulation."
When you put a road block in the way of evolution, you don't get stopped traffic. You get monster trucks that roll over the road block, off road vehicles, airplanes, and tunnel borers. Life won't stop. Trying to stop it is one thing you can do to make the gods laugh.
Of course you can only say "might" and "maybe." These are complex systems with loads of internal feedback loops and lots of interacting selective pressures and such. You can't predict them in any definite way. Psychohistory (ala the Foundation trilogy) is fantasy.
What happens after ten generations of selection for the ones who reproduced?
(This is also a major reason I think the current right wing fertility panic is mostly bullshit with the exception of maybe a few places with unusually low rates of reproduction.)
You’re talking as though the only decision behind reproducing is an active rejection of contraception. Whilst this be practically happening during the fecund period, it is hardly the only influence and is certainly not responsible for the decrease in average fecundity women have seen across the world. The idea that this is a trait that is going to be selected for when every breeding pair are part of it is patently ridiculous to my perception, there is no population bottleneck or significant progeny advantage that you are gaining against every other reproducing couple that drives an evolutionary advantage; and we’re certainly not going to be able to select for a shorter gestation or increased/earlier independence of the young
> we're certainly not going to be able to select for a shorter gestation period or increased/earlier independence of the young.
I've decided to not have kids until artificially sentient children are a thing - and I'm hoping to find like minded individuals. Hopefully our work will help pave the ground for artificially sentient humans, and establish hybrid families of biological and AI humans.
And my AI babies will probably have faster gestation and development times than normal human babies.
But they're still going to be my babies. l will consider them human offspring, assuming I can properly socialize and humanize them. And maybe many humans will make similar choices to have artificial children.
So the range of standard gestation and child rearing times could change a lot, perhaps over a very short period!
That said, I wanted to ask a question about your argument. OP argues that the cohort of contraceptive users will simply select itself out of existence by choosing to reproduce less. You seem to argue that this can't happen because all breeding pairs are part of the global drop in fecundity. If it was happening, the trend would be for higher fecundity, not less.
That makes a strong argument for the present. Does that dismiss their claim that the drop of fecundity will lead to a critical situation where fertility collapses, and it's up to reproductive rights deniers to save the day? The reason I want to dismiss that argument, in no unclear terms, is that I believe it may be a sort of indirect or wishful thinking eugenic argument. The moral failings of reproductive rights advocates are supposed to end up ironically being the mechanism for their own genetic culling. It sounds fishy.
What do you think will happen after ten generations, when population will start to grow exponentially? Will Dyson swarm, food, shelter and infinite resources immediately materialize ex nihilo?
> Are there intelligent beings with a drive to limitlessly expand their population?
Let's assume a few things. They're biological (for what passes as biology on their planet, anyway), and evolved from what were originally single-celled organisms. They didn't blink into existence as Boltzman Brains or something like that. Also, they are a group of individual beings, and it wasn't some sort of global hivemind with a singular being surrounding the entire planet like some coral or whatever.
If these assumptions are valid, then yes, they'll have a drive to limitlessly expand their population, because those species that didn't have this drive became extinct in their prehistory. They'll be puzzled by it, might go through a phase where it causes them the equivalent of shame, then they'll grow past that and not care once again. And they'll expand. Because not expanding risks extinction, just like it does with us. We either expand to multiple locations outside of our planet, or we risk extinction.
> Are there plausible social arrangements stable enough to last the duration of such a project?
Maybe not. Who cares. If in the 20th century we became aware of a human Dyson spehere half-built in our solar system, a million years old and unfinished, you think we wouldn't turn around and start finishing it? Social arrangements may be unstable and cause minor disruptions, but so too are minor disruptions unstable and humanity might return to the norm on timescales relevant to the construction of a Dyson sphere.
> Is there enough time in the lifetime of a star to build and use those structures?
This is a good question. I don't know the answer to it. We've got, what, another billion years or two in ours? If the construction only takes a couple million years, seems like it might be worth it. Though the thought of the cost overruns and so forth should make even the mightiest bureaucrat shrink in terror.
> A lot of the ideas behind hypothesizing swarms of space structures, each orders of magnitude more massive than Earth, feels very 1970s population/energy-crisis inspired.
I find this hilarious in ways that I can't put into the words to share with you just how funny it is.
We don't necessarily need to build a Dyson sphere to reach other planets and stars.
And if the Dyson sphere gets built by an aggressive singularity to the tune of Stross' Accelerando, then pretty much every human in that singularity's light cone is at serious risk. If that happens, we may have to broadcast human mind vectors out into the galaxy and hope a less awful singularity catches us and gives us a simulated home with reasonable Mind Rights.
Humans have a survival impetus to settle multiple planets and star systems. But a fast burn self improving Dyson swarm might easily create more risk than it alleviates. We might therefore choose to stick to more conservative technologies to hit the stars, even with all your assumptions in place.
Slow growth swarms might be safe if there's physical reasons that a fast burn Dyson sphere is impossible. But if we uncover the potential for fast burn, we could enter a "swarms race", warring to achieve and control the most effective and rapidly accelerating swarm. In this setup, each major political power tries to start a fast burn, because otherwise an enemy will achieve it first and wipe out your swarm. The result could be, for example, multiple runaway Dyson swarms, fighting each other without our control.
Now, saying all this, I still think it would be fun to build a self improving and self replicating swarm. I just don't know if it would be very safe, politically in the short term, and for the species in the long term.
Between expansion and shrinking, their is this razor-thin third option, where you are perfectly breaking even. Which is impossible to achieve in practice, even if theoretically it looks like an option... any unanticipated event threatens to cause unplanned shrinkage. That needs to be repaired immediately, but there is no generalizable plan to expand back to the prior level and then stop immediately, far too easy to overshoot. These instabilities last for decades or centuries, and if another event happens before stabilization, they just continue forever.
> Is there enough time in the lifetime of a star to build and use those structures?
If a brown dwarf, most certainly
> Are there plausible social arrangements stable enough to last the duration of such a project?
Could just be an unterminated machine process initiated by living beings at some point
> Are there intelligent beings with a drive to limitlessly expand their population?
This one, I agree. I think once we start expending enough we'll realize there's only so much that extra matter and energy will get you and it doesn't bring you closer to "solving" the universe or escaping it and you just stop going for more.
One aspect that I find problematic with the idea of Dyson spheres is: where will the energy be dissipated? In the civilization's planet's surface? It seems to me that it would create serious energy imbalances and soon climate disruption.
One solution to this is the Matrioshka brain, which consists of many nested "shells" around the star. Each one absorbs the radiation from the hotter shell inside it (or from the star, if the inner shell), and radiates waste heat to the cooler shell outside it. The temperature differential between the inside and outside of each shell is what allows work to be done. The outer surface of the outermost shell, maybe 5 billion km (~35AU, or a bit further out than Neptune) from the star, will be close to the ambient temperature of the interstellar medium, and will radiate heat at only a few Kelvin into it.
Isn't the point (and I could be wrong) with a Dyson sphere that it should have a spectrum that approaches that of a perfect blackbody radiator? Or would any radiation that sneaks past the swarm drown out the blackbody spectrum?
> Isn't the point (and I could be wrong) with a Dyson sphere that it should have a spectrum that approaches that of a perfect blackbody radiator?
Pretty much. The lower the temperature of that blackbody radiator, the higher energy you can extract via temperature difference. Until you reach the background radiation of the universe, which could be considered the lowest possible temperature of a thing that still extracts energy.
> Or would any radiation that sneaks past the swarm drown out the blackbody spectrum?
If that's the case, you can improve your sphere and capture that extra energy.
See my comment for a more detailed explanation but the short version is: a Dyson Swarm (preferred term) is merely a cloud of orbitals (ie not a rigid shell; there is no known or even theorized material with the strength to build a shell that large). The orbitals dissipate heat into space. That's what the infrared radiation is that they're looking for.
I see that. My point is that if the captured energy is used, and thus ultimately dissipated as heat, on the planet's surface, that planet is sooner than later going to have climatic imbalance.
First, the Earth already receives a ton of energy from the Sun that is "wasted". We estimate that at about 10^16 Watts of power, compared to humanity's energy usage, estimated at 10^10-10^11 watts. So Earth has a ton of energy dissipiation "built in" that we're not "using".
Second, there is some inefficiency and thus heat dissipation in converting solar output into usable energy. Doing that in space means a bunch of heat dissipation happens in space rather than on your planet.
Third, it's relatively straightforwward to counter any increased heat dissipation on your planet by reducing that solar output that hits your planet. How? You build something at the EArth-Sun L1 Lagrange point. Reducing that solar output that hits the EArth by 1% would likely be unnoticeable to us but could cool the Earth significantly. Also, what do you build there? Well, lots of things. More orbitals, solar power collectors, etc.
Fourth, how do you get power down to a planet? There are several candidates. One is to beam it down. This adds a conversion cost. But here's another: you build a n orbital ring [1] 100-150km above the EArth's surface. There are a ton of reasons you'd want to do this: interplanetary travel, cheap travel to and from LEO and easier travel across the planet (ie up to the ring, down to another point on Earth on cable cars, basically). But consider this: it gives you a rigid structure to attach solar power collectors to and you can run power transmission cables down from the ring to the planet's surface.
I wonder how much reaction mass we’d need every year to keep something stationed at a Lagrange point to block 1% of earth’s light, for combatting global warming. 1% of earth’s light would be a heck of a solar sail.
Looks like 1% would be 13.3 watts per meter, cross section of earth yields ~5.4x10^14 watts. Assuming perfect reflective, multiplying by 2/c gives 3.6x10^6 N. So like half of the thrust of one of Saturn V’s engines? So… a lot of reaction mass, or some really powerful ion engines and a ton of power. So maybe not the most practical idea.
It's true that the L1 Lagrange point is unstable so would need some station-keeping. It's an issue but it's a solvable issue. For one thying you have a bunch of energy to spend. For another, the solar wind itself can be used to provide momentum going out if what you have there is sufficiently light.
But there's another option: statites [1]. Statites are solar power collectors that have an incredibly thin sail to the point that they don't need to orbit the Sun at all. This means you have a bunch more options for positioning. Clearly the Earth will continue to revolve around the Sun but a sufficient swarm of statites on the EArth's orbital plane could have the same net effect as, say, driving beneath a bunch of stationary umbrellas.
Or statites can themselves do station-keeping at L1. They can angle themselves to provide momentum in a bunch of directions. Or they can orbit the L1 point similar to how JWST orbits L2. Their ability to use the solar wind for directional momentum could satisfy station keeping needs.
Besides the unstable nature of L1, my main concern was actually mitigating the light pressure of the light being blocked, in order to not be blown earthward, but I guess that’s not really considering that these things could manipulate their solar sails/shades like the statites you’re mentioning.
Its not where energy is sourced but wher its used. And assuming it will be civilisation's planet like Earth. The whole energy of the swarm will be used there. - It just has to increase temperature (due to additional energy on the planet)
If they can build a sphere or swarm megastructure then obviously they would have build orbiting habitats either from scratch or terraforming planets or astroids.
> The whole energy of the swarm will be used there
that sounds like a made up problem. the Dyson swarm isn't to collect energy to send to the home planet. it's to collect energy. where that is used is going to be wherever it's needed. mining the asteroids, local computing (the cloud is no longer just a computer on earth, it's the cloud of the swarm elements), powering interstellar trips remotely, etc. the only thing that needs to get to earth is the imports of goods and services.
That actually makes no sense. You can't use (destroy) energy, you can only run it through processor, which will change it into heat while transistors inside are switching on/off. It is like a water wheel doing work by water flowing through it, but ultimately amount of water before and behind water wheel is same.
Thus the question still stands, what happens to heat in such thing? Does it get recycled by some unknown device? Then it is closed system, you don't need input from outside. It won't get recycled? Then such device needs to get hot from dissipating that heat.
We are using the sun's energy that hits the earth. Some as light (which turns into heat), some as electricity (which turns into heat), and some as plant food > animal food > oil (which turns into heat)
A Dyson sphere would capture the sun's energy that leaves the sun, not just the fraction that hits earth. Using that energy on earth would release far more heat than our current activities.
My assumption is if you demand the energy needs of a dyson swarm you’ve probably figured out how to convert this energy to work with none of it lost to heat.
Presumably to fuel things we could not conceive of given our relatively pedestrian in comparison energy needs. But, there is no free lunch. Work takes energy away from the system even with no heat loss by virtue of doing something with that work using energy, as we know from our most basic physics courses that assume a frictionless spherical cow with no heat loss.
Energy can't be destroyed. That's basic physics. Work of any kind is just turning usable energy into unusable heat. If you would have such device which can take heat and turn it into usable energy, then you would just need to take a system, charge it and it would be working forever. Unfortunately this is some Clark-tech level of magic technology.
How is this hard to imagine for you that heat loss can be minimized to the point of being effectively zero? Even with present tech we have a variety of heat loss efficiencies. No energy needs to be destroyed this is just what you convert in this case all converted to work.
Whole concept of Dyson sphere/swarm is anachronistic. It is like trying to build the Internet based on carrying pigeons, while you have available fiber optics and advanced radio communication. Because the moment you have enough technological advancements to build and deploy such a thing, you can already build fusion reactors by million units a year and maybe you already have even better ways how to manage energy. In the end the matter itself is just a different form of energy.
That's a very optimistic view of the future of fusion, IMHO an unreasonably naive view. There are lots of problems with fusion that are unclear if they will ever be solved, specifically:
1. Energy loss from neutron escape. Stars don't have this issue because they are incredibly large (so your neutron will hit something else more likely than not) and gravity;
2. Vessel destruction from lost neutrons (ie neutron embrittlement);
3. Assuming D-T fusion, you're producing helium atoms. Helium is a pesky substance. It's chemically neutral and a helium atom is (AFAIK) the smallest atom, even smaller than a hydrogen atom. That means it is hard to contain and also has a tendency to damage your container;
4. Fusion reactors are, in a way, somewhat primitive. Why? Because ultimately you generate heat and turn a turbine like we do in every coal and natural gas plant. Moving parts are bad.
5. Fuel. Depending on what fuel you need, this is somewhere between a small problem (eg protium or even deuterium) to a hassle (eg tritium) to a major problem (eg He-3).
6. Waste. This depends on fuel somewhat eg do you need to use fissile materials to create Tritium?
Much more detail [1].
We obviously don't know the economics of fusion yet because it doesn't exist, but the economics of nuclear fission are, well, terrible (in both capex and opex terms).
Once you put a solar panel in space, it produces ~7 times the power. There's no loss to cloud cover, getting covered in dust/dirt, atmosphereic loss and the day/night cycle.
For an orbital, you simply cover the exterior with solar panels and you're done for power generation. No moving parts, no catastrophic failure modes (eg meltdowns in nuclear plants), it's scalable and when panels break down you simply remove them and plug in a new one.
I expect other forms of power generation will find a niche use far from the Sun in the same way that submarines have different operating characteristics to a suburb. But I'm skeptical fusion will ever be the preferred method of power generation.
1. You don't have a way how to transfer power from Dyson swarm without absurdly staggering losses.
2. Dyson swarm satellite would be heated up by incoming heat from Sun on one side and heated up by whatever mean you want to transfer that energy on the other side and unable to cool itself down because it is in vacuum of space. So even that power on the paper is eye popping, actual power would be fraction of a fraction of nameplate power because then you would overheated and destroy it. And now question would be, is such constrained satellite able to make more energy than it was invested into making of this satellite?
Combine 1 and 2 together and real output from such structure would be close to zero.
> You don't have a way how to transfer power from Dyson swarm without absurdly staggering losses.
Why do you need to transfer power? The point of an orbital is primarily for people to live on. A single orbital could potentially support a million or more people.
Are you referring to the issue of providing power to Earth? That's... a separate issue, with different solutions. The idea of power satellites [1] has had a lot of thought. An alternative approach is to build an orbital ring [2] and hang solar power collectors off of it. You could this power directly to the ground with transmission lines.
> Dyson swarm satellite would be heated up by incoming heat from Sun on one side
An orbital would be heated on the side facing the Sun and radiate away heat away when not facing the Sun in the exact same way that the Moon is scorching hot when facing the Sun and 200 below zero when not.
Yes, thank you for asking a clarifying, good-faith question in order to learn. In fact, the habitat part isn't even required!
A dyson swarm is just a bunch of satellites, each harnessing energy from a the same star (what they do with that energy is up to them). 1 satellite is the singular form of satellites. No need to alert NASA, they already know :)
The good news is that it seems you might be just now learning that humans have the beginnings of a dyson swarm already in the works. What a great day for you!
Oh what a bad faith response trying to have some moral high ground. The Dyson swarm as defined are satellites close the the Sun collecting energy, where it is dense and relaying it further nothing else. Trying to compose there something else is moving goal post and then is not a Dyson swarm.
With this goal post moving we can start claiming that Oort cloud is a Dyson swarm. Or are all stars in this galaxy a Dyson swarm moving around central black hole? Maybe if we will move goal posts further they will!
With the ISS being "close to the sun" in my opinion (close enough to capture energy), and with the "relaying it further" not actually required for the term (all the energy can be used locally, and it still applies), it seems that the ISS does meet the definition.
Also, while I assumed good faith in my above reply, you've dashed my hopes: please don't ask bad-faith questions here. This is the wrong forum for that. You've shown yourself capable of announcing that you personally disagree with something. I think politely doing that is better than asking bad faith questions, pretending to want to learn, while intending to argue with the answer.
The sun burns around 600 million tons of hydrogen per second https://cosmicopia.gsfc.nasa.gov/qa_sun.html
I don't think you building a million new fusion reactors per year so that each of them burns maybe 100kg of hydrogen per year even starts to be comparable in a few thousand years.
The energy emitted by the sun is just several orders of magnitude beyond what you can source from a planet. It's just that huge.
But I can carry such reactor into Oort cloud and beyond. I can power my ship in a shadow of a planet or asteroid and most importantly I am not dependent on one megastructure, which can fail, be destroyed or taken over by hostile forces.
The dyson sphere can power a huge factory, capable of making thousands if not millions of warships per second. It can also power a star-sized laser capable of vaporizing pretty much any incoming army, or even bigger objects like small planets. Your dyson sphere will be safe to everything but civilizations capable of playing marbles with stars and black holes.
Also you can use your star-sized factory to make starships with fusion reactors. Not a problem.
But if you want to get beyond Jupiter, then whole Dyson swarm is useless to you, because you don't have source of energy. And again when somebody will get control over such swarm, then such person has control over whole civilization around that star which was foolish enough to build it and rely on it at a first place.
What stops you from using a bit of the sun's output that you are capturing to materialize a starship with it's own reactor and thrusters, and then open a window in the sphere to let that ship leave?
I mean, it looks like you want to _contain_ all the energy of a sun for the sake of containing it, not to do cool stuff with it.
Dyson Sphere seem like what we would do based on our understanding of physics would do, and of course how else would you theorize such device? My theory is that an advanced civilization would not need to brute force such methods and use novel physics to gather energy, fusion is a start but there has to be even more advanced methods.
I still don't understand why you need to build a Dyson sphere and then transport the energy to where it's needed when you can build decentralized fusion reactors. What am I missing?
The reason to build a Dyson Sphere (or Swarm) is that you want all (or at least a large fraction) of the energy output of a star. To "build decentralized fusion reactors" that can provide the same scale of energy is even less practical than building a shell around a star and would require far more materials! Also, fusion is really simple when the ignition energy is provided for free by the gravitational compression of something the size of a star, and not so simple when you're trying to get it started on a small scale using any other form of energy for ignition. The bottom line is we don't really know if small-scale, controlled, net-energy-positive fusion is possible at all, but if it is it has a lot of overhead costs... you then have to deal with ignition energy, containment, etc. You're trying to make a mini-star and keep it tame. The physics are not favorable to this, they are favorable to star-sized stars, where gravity and fusion energy pressure can balance each other for millions of years.
The concentrated energy of Dyson Sphere can be very useful. Feed some of it into lasers and then launch starships and then slow them down when they get to destination. Not tiny probes with fusion reactors but full size starships.
Feed most of the energy of star to lasers and end up with weapon that will melt planets across the galaxy.
Honestly, don't need to expand across the galaxy if have Dyson Sphere, which could be explanation of Fermi Paradox.
Diffraction limit determines the fundamental beam divergence angle theta = lamda/pi/D, where D is the beam diameter, lamda is wavelegth of elwctromagnetic radiation (eg. light).
To minimize theta, we need to either increase D or decrease lamda.
Lets assume we would be able to make far infrared high power lasers, at say 10,000 nm = 1e-5 m wavelength.
Lets assume we would be able to make D, the diameter of our laser beam, similar to the diameter of a typical planet, for Earth it is ~13,000 km = 13e6 m.
Theta = 1e-5 / 3.14 / 13e6 ~= 1e-13 radians.
Sun is ~ 25,000 light years from the center of our galaxy, ~= 25e3 y 3e8 m/s 31.5e6 s/year ~= 1e20 m.
Laser beam diameter, there far away, would be: 1e-13 *1e20 = 1e7 m, similar to the diameter of Earth, not much further diverged, focused and delivering the wast amount of energy all over the planet thereby evaporating it to a gas.
Indeed, what you say about the melting far away planets is possible, in theory.
Can you build decentralized fusion reactors? This far the most efficient fusion reactor humanity has available to it exists approximately 1 AU away and is rather difficult to relocate.
The technology for a Dyson sphere is primarily the technology for suspension bridges, solar farms, and intensive hydroponics (all well understood) + the technology for the ISS (well understood at this point). The only missing piece there is a fully sustainable (i.e. only energy input) life support system, which we have existence proofs for on Earth but haven't built to reliable engineering standards yet. If we have the material, we could start building it today and get designs that worked well quickly, even if we had to ship in life support maintenance alongside computer chips & pharmaceuticals.
The part we don't know how to do yet is getting the material. Building structures that large in space, the resources for it have to come from space, we cannot lift it off Earth. So we need to figure out how to mine asteroids, and maybe also how to mine Mercury. Either one would be sufficient at the start. Neither of those are a well-understood problem, let alone solved, so that's where you should invest resources if you're a billionaire looking to start a Dyson sphere and think SpaceX is on track for launch cost reduction.
I think in terms of science and engineering difficulty, it's a pretty even race as to which is more difficult between making fusion actually produce net useful energy and being able to mine & refine materials from an asteroid + build a sustainable life support system.
The reason fusion "seems easier" is because it is economically far more achievable, and there's a lot more political will behind it so it feels more possible.
The ceiling on asteroid mining is orders of magnitude higher than anything constrained to earth. Put another way, imagine if you owned Australia because your company built it up off the ocean floor.
The sphere does not need to be built or owned by a single entity. You too can own a single unit of the sphere for the low, low price of $2T. There can be different corporate entities owning different sections and monetizing it in all kinds of ways (e.g. the KY sector is ideal for powering asteroid mining in the Kuiper Belt)
I hear people often talk online saying energy in the future will be either free or very cheap.
Dont know what cheap means for them, but it will never be for free because abundance happens when the supply exceeds demand and I dont see the scenario where the demand for energy is declining in a long run.
Well, I guess the argument would be that a billionaire financing the construction of space habitats could make them effectively company towns, but of a highly educated workforce. Once enough of them are there they'll have their own economy, and whoever owns them/the oxygen supply/whatever would be getting a lot of return. I don't think that's a great argument, though, for multiple reasons. I think it's better to just frame it as building a legacy. Put humans in an entirely new place that many of us desperately want to be, end up having the equivalent of a city named after you.
Are you claiming that it is not possible to put a satellite into an orbit around the Sun? Please take a look at how many times this has been done already: [1]. Now just capture Sun's energy on one and do something useful with it: part of Dyson swarm.
It is possible to send a singular satellite pretty much anywhere. It is not possible to build and maintain a Dyson Swarm. At the sizes of modern satellites you'll need trillions of those, which is completely unrealistic with Earth-side launches. This is before we get to doing them any actual dyson swarmy work: so far our probes are only good at communicating and observing.
Dyson Swarm in particular is a megastructure harvesting much of the star energy to the extent its spectrum is dramatically shifted to infrared. I can't stress enough that a lone satellite is not a swarm, Dyson or otherwise.
A dyson swarm is just a bunch of satellites, each harnessing energy from a the same star around which they are more or less are situated (what they do with that energy is up to them). They harvest a proportion of the star's energy anywhere on the range between 0 (non-inclusive) and 100% (inclusive). Your description is one possible end state of a Dyson swarm, and itself includes a subjective measure (what you consider dramatic might not be what I consider dramatic).
Your description of it as a megastructure might explain some of the confusion: it wouldn't be a structure, but rather a formation of satellites not physically connected to each other.
How do you build a swarm of satellites? Well, first you make 1 satellite, then you make another... :)
> Your description is one possible end state of a Dyson swarm, and itself includes a subjective measure (what you consider dramatic might not be what I consider dramatic).
My description is Freeman Dyson's description. Naturally you are allowed to come up with ImPostingOnHN's Swarm, which includes a case of zero satellites and no effect on the star emission whatsoever.
> How do you build a swarm of satellites? Well, first you make 1 satellite, then you make another... :)
Sure and the end state of completing Dyson Swarm in Solar system is not achievable with the technology we have. Now let's move on to discuss if one man with a rifle but no vehicle constitutes a Motor Rifles brigade.
> Sure and the end state of completing Dyson Swarm in Solar system is not achievable with the technology we have.
Sure, for one possible end state.
The point is that we have the technology to start, because we've already started. Thus, it is achievable given enough time and effort with our current level of technological advancement.
How do you get energy from there? How do you deal with waste heat of satellite which is being heated up by sun from one side and heated up by your mode of energy transfer from the other side?
Unless we have some magical solution which can convert waste heat into electricity and thus making such satellite working with 100% effectivity, then such satellite needs to transmit energy with very limited power otherwise it will fry itself up.
Why 100% now? None of those satellites are exploding right now from overheating. Just add a laser on each pointed at somewhere where the energy can be used, done.
None of those satellites are also trying to collect as much energy on one side and beam them on the other side. Notice how those satellite closer to the Sun are wrapped into reflective and isolating materials and only antenna, solar panels and sensors are sticking out.
Additionally high power laser has currently something around 80% of efficiency. So if you have 10kW of input from solar array on one side, then you are transmitting 8kW via laser and 2kW into satellite itself as a heat. And again, we are in vacuum of space, so good luck with radiating 2kW of power into vacuum.
The fact, that you can't get rid of waste heat would need whole satellite to work close to 100% effectivity, which we don't have technology today
Fusion reactors will probably never be economical.
It's the railgun problem: railguns let you trade complicated, unstable ammunition for cheap, stable slugs of metal. But the railgun imposes so much wear on its barrel, and the barrel itself is so much more expensive than in a traditional gun, that you've obliterated your cost savings.
Likewise, it's irrelevant if fusion reactors can provide infinite energy from a single gram of hydrogen, because the reactor housing itself will be an impossibly complex machine with an extremely low lifespan from dealing with the energies involved.
Is fusion possible? Probably. Will it ever be more economical than solar panels? Nope.
Solar panels would be nowhere near as effective far away from a star. Building things as far out as Jupiter or to traverse interstellar areas can't rely on them.
I like the railgun analogy. I think you can stock up on other fusion cost arguments through my article, Engineering and Economic Challenges of Fusion: https://lvenneri.com/blog/ConFusion
I know nothing about railguns, but if they are supposed to launch the projectiles with magnetic force then why do they need to impose any wear on its barrel at all? Couldn't you build a railgun where the projectile never even touches the barrel, being kept at the center by the same magnetic field that accelerates it? Or are we talking about the wear imposed by the magnetic field itself?
If I recall correctly, a "railgun" per se is one that uses the projectile to conduct electricity between the "rails" that direct said projectile. So there's contact, between parts moving hypersonically relative to each other.
It would seem that even without contact there's wear issues with both force exerted on the rails or coils from the magnetic forces and also with creating plasma as the projectile exits?
It's like an 1800s dude thinking aliens would do interstellar travel by having very huge horses, oh no wait...a billion of them (but still somewhat big)
"This is what an advanced race would do...with our current understanding" is an oxymoron
I'm guessing it's more like making a living space in the sphere itself or somewhere nearby and using the energy there (maybe exporting some percentage to Earth).
Because if we're able to build the sphere itself, we probably would already know some way to cool it down in space so it doesn't burn itself, wasting all the money that went to its construction.
I wonder if the material of all the stuff in our sun's orbit would be sufficient to build a dyson sphere. Afaik, 99% of the mass of our solar system is the sun itself...
To build about a billion O'Neil Cylinders, which is about the number you'd need for a full Dyson Swarm around our Sun, would consume (IIRC) 1% of Mercury's mass.
Lets assume the Dyson swarm would be built at 1 AU or 149,597,870,700 m ~= 150e9 m from the Sun.
Lets assume energy converting photovoltaics will be made of non-crystalline materials with a high light absorption coefficient allowing solar cell thickness of ~100 nm = 100e-9 m.
Sphere surface is 4pir^2, in our case 43.14150e9^2 = 3e23 m2 * 100e-9 m = 3e16 m3 is the total volume occupied by a Dyson swarm tech.
For comparison the volume of matter that Earth contains is 1e21 m3, which is 1e21/3e16 ~= 1e5 = 100,000 times larger than what is required for a Dyson swarm.
Which begs the question, how do you obtain sufficient energy to go scouting for material beyond the solar system in order to construct something that encircles the sun…
You figure out how to put a fusion reactor on a spaceship without melting the whole thing into a blob of metal and use a particle accelerator as a super high isp engine.
Yeah you need to work very hard to lose heat without losing mass in space. Basically you can only radiate it away, which is slow; there are ways of concentrating heat in one spot so it is radiated more efficiently, but that’s where you get to the melting part.
Consuming Mercury would give you a 2x car sheet metal thick full dyson sphere made of iron.
Earth, Mars and Venus each have about 10x the iron of Mercury. The asteroid belt is inconsequential.
If you consume all the iron core planets, you have about 5 cubic centimeter of iron to play with for each square centimeter of dyson sphere area.
There's a lot of unknowns for the gas giants, particularly what % of them contains iron, but Jupiter /might/ have as much as 100x earth heavy elements (including iron), but these would be at its core, and its not totally clear how you would extract them.
I think the key question is what sort of stresses you expect the sphere to be under, and thereby what materials and tensile strengths are required. It would not surprise me if the stress is basically nil (in theory you could orbit a sphere made of iron dust?) or totally infeasible for iron.
I don’t think proportion of mass is relevant here. An apple peel is maybe 3% of the mass of an apple, and a Dyson sphere would be a proportionally much thinner “skin” around a star than an apple peel.
I love this topic. If and when we detect a technologically-advanced civilization, I truly believe this is how we'll do it. But why? Because the Dyson Swarm (the preferred name; "sphere" implies a rigid structure that was never the intent) is seen by many as the most likely path forward for any spacefaring civilization. Why? Several reasons:
1. It can be built incrementally. What you'd probably do is build orbitals and put them in Earth's orbit around the Sun, Then you can keep adding new orbits. Ultimately you end up with a "cloud" of orbitals that will block a star's light in the same way that water molecules in a fog block light;
2. A likely candidate for an orbital is waht's called an O'Neil Cylinder: 3-4 miles in diameter, 10-20 miles long, producing Earthlike gravity on the interior by spinning. Smaller than this and it needs to spin too fast. Larger than this and you need stronger materials to stop it ripping itself apart from centrifugal forces. Stainless steel is sufficiently strong to build an O'Neil Cylinder;
3. Solar power is the most likely source for our future energy needs. It's the only known power source that directly creates power and it does so with no moving parts and no waste produced. In space, solar is so ridiculously efficient that it's unlikely fission could ever compete economically and fusion is still a pipe dream.
4. Approximately 1 in 10^9 of the Sun's output hits the EArth. That's an awful lot of "free" energy just radiating out into space. The growth potential is huge. What do we need all that energy for? History has shown we'll find a use but here's a big one: the energy cost of interstellar travel is so mind-boggling large that we'd need something like the Sun's energy output to do it. Plus an interstellar generation ship looks an awful lot like an O'Neil Cylinder.
Anyway, the article doesn't really explain why the seaerch for infrared radiation that I could see (maybe I missed it?). It's important.
A body in space like an O'Neil Cylinder will heat up, even with converting some of that energy to electricity. The only way to cool down in space is to either expel mater, which doesn't really scale, or to radiate it away into space. The wavelength of light from a radiating body is determined entirely by the temperature of that body and for any temperature we're likely to see, that means infrared radiation.
So if you look at a star with a near total Dyson Swarm you'll see much less visible light and much more IR radiation and there's really no way to hide that. Some might say you can capture the heat an turn it into energy but you can't do that with perfect efficiency (ie thermodynamics) plus the material of the orbital will just naturally radiate anyway no matter what you do.
It's extremely conservative to say that we'll have the technology to build and deploy an O'Neil Cylinder within 1000 years. Give it 10,000 years if you really want. It makes no difference. That's still the blink of an eye in cosmic terms. And that gap between having 1 and a billion is also the blink of an eye.
And once you have what's called a K2 (Kardashev-2) civilization (being one that uses the full energy output of a star) where interstellar travel becomes possible, even practical, seeding a new Dyson Swarm around another star becomes trivial and the proces continues to the point where 100 million years from now is a completely realistic time period to have a Dyson Swarm around every star in our galaxy.
A galaxy of Dyson Swarms would be so obvious to observers even millions of light years away, even at our current level of technology. The absence of seeing such a thing contributes to the idea that spacefaring life is incredibly rare.
"A likely candidate for an orbital is waht's called an O'Neil Cylinder: 3-4 miles in diameter, 10-20 miles long, producing Earthlike gravity on the interior by spinning. Smaller than this and it needs to spin too fast. Larger than this and you need stronger materials to stop it ripping itself apart from centrifugal forces. Stainless steel is sufficiently strong to build an O'Neil Cylinder;"
It's unclear what exactly you mean by "too fast", but assuming you're referring to human tolerances: human tolerances from NASA + Soviet studies put unambiguous, continuous tolerance without needing medication or training or anything else at 2rpm, which equates to a diameter of 450m. That is a lot smaller than an O'Neill cylinder and a lot more feasible to build sometime soon. IMO the best option is to build a 100m diameter testbed now from Earth materials, as the successor to the ISS. Then take the lessons learned there and build a 450m diameter prototype, which we can use space materials for if space mining has developed enough. We could technically throw enough material into orbit for a 450m diameter cylinder but it would be a lot of material. Any of the larger sizes and we'd need real-deal asteroid mining to make that happen.
Basically, build a small testbed now to conduct actual experiments on human health at different gravity levels + RPMs, and also start trying to figure out asteroid mining. Build a bigger prototype habitat once we can get materials for it, either from massive launch cost reductions or asteroid mining. After that point we really do need asteroid mining.
Well, so is building Dyson swarms and spheres. I'd bet that we will figure out fusion first.
> much more IR radiation and there's really no way to hide that.
Maybe you can create a black hole in orbit and radiate into that? I saw somewhere that it might be possible to create a black hole using less hydrogen than what is available on Earth.
> Well, so is building Dyson swarms and spheres. I'd bet that we will figure out fusion first.
Dyson Swarm doesn't require new technology. It is nothing but a collection of objects orbiting and gathering energy to power its own processes. We have satellites that orbit Earth but gather energy from the Sun.
By that yardstick fusion doesn't require new technology either. Humans successfully performed nuclear fusion many times since 1950s and there are thousands ready packaged fusion devices around the world.
Building a Dyson Swarm, which is really just the problem of creating one self-sustaining orbital (since after that it's just a scaling issue) is really just an engineering problem. A huge one of course but we already have teh technology to create a material as strong as stainless steel and to build solar power collectors.
Currently, the big cost is getting material into space. LEO payloads are still (AFAIK) >$1000/kg. Getting that to $100/kg or even $10/kg completely changes that equation and yes, there are viable paths to reach that (eg orbital rings).
Fusion isn't even an engineering problem yet: it's a science problem. The big problem is energy loss from neutrons (as well as those neutrons destroying your reactor). That's not a problem for stars. They have gravity and are simply so large that the vast majority of neutrons are captured and feed into the overall process.
It's not clear we'll ever reasonably solve these problems. A fusion reactor is large and expensive and has many moving parts since, ultimately, we just use heat to turn a turbine in the same way a coal or NG plant does. Plus it needs fuel. Over long timescales that's still a problem. What fuel? Helium-3 (for so-called aneutronic fusion) is a big problem to source. Deuterium is easy to get. Tritium is harder to get. Protium is obviously easy to get.
Nuclear power as it currently stands on EArth cannot compete with the cost of solar power with solar panel efficiency still going up. What happens to that when you put that solar panel in space and now it's producing ~7 times as much power since day/night and weather are no longer factors and there's no energy loss to the atmosphere?
This is why I say "if" nuclear fusion will ever be economically viable. I'm not saying it won't be but there are massive hurdles to even theoretical economic nuclear fusion.
A lot of thought has gone into this and other possible explanations. Isaac Arthur, of course, has an excellent video [1] on this issue. His entire library on the Fermi Paradox is worth watching.
The short version of why this seems unlikely is that there really is no hiding a K2 civilization for many reasons. For example, access to this much energy and having a megastructure as large as the Solar System (give or take) would allow you to create incredibly high resolution telescopes (with an without interferometry).
But consider this: if you, as a spacefaring civilization, want to be left alone, the best way to do it is to make sure nobody comes into your neighbourhood. If you "hide" that may happen accidentally. Isn't it better to advertise your presence and otherwise keep people away to avoid unintentional conflict?
Many challenges become a lot easier when you have 10,000x more energy. Start building Dyson satellites and you will quickly have the energy you need to create solutions for your problems
“The wavelength of light from a radiating body is determined entirely by the temperature of that body and for any temperature we're likely to see, that means infrared radiation.“
IR metamaterials change this, you can alter matter at the nanoscale and completely change it’s black body .
Very curious to see what other astronomers think about this in the comments. My gut feeling is there are almost certainly natural explanations for these. Just seems unlikely we would only be starting to see these now, even with the greater resolution of telescopes & increase in compute to crunch through the data.
If there were 7 of these ripe for the plucking that were actual Dyson spheres, each one would be the single greatest discovery in all of humanity. Just seems a little too easy.
Bayesian reasoning applies here. Natural phenomenon is the most likely cause.
think of it this way: imagine in the future we travel to Alpha Centauri and find sentient life or even the remnants of such. That would be really bad. Why? Because if there are 2 civilizations in our galaxy, how likely is it that they're next to each other? Incredibly unlikely. It heavily implies that sentient life is much more common. Now imagine if we find a third at, say, Barnard's Star.
In Fermi Paradox terms this heavily implies that there is a Great Filter ahead of us and we're more likely doomed than not.
Finding a Dyson Swarm near us has the same negative implications (for us), especially given that the gap between a partial or full Dyson Swarm and colonizing the galaxy is relatively small (~100 million yaers) in cosmic terms so how likely is it that we find a Dyson Swarm that is a) near us and b) in that narrow window between the emergence of spacefaring life and colonizing the galaxy.
That doesn't track. The fermi paradox is "we don't see evidence of intelligent aliens, even though we expect them to be abundant" and the great filter concept is merely an argument for why they would not be abundant.
If we find abundant evidence of intelligent life, there is no fermi paradox, and thus there would be no reason to explain life's fictional rarity. The answer to "where are they?" is "right over there."
How does one tell the difference between a partial Dyson swarm, and occlusion by planetoids, especially in the early stages of development before the planets are formed
No, it's a case of if we presuppose the existence of Dyson spheres, here are 7 objects whose EM spectrum matches what would be expected of such an object and who have no other verifiable explanation.
It's not saying we don't know what causes lightning therefore it must be gods. It's saying we have expectations of what lightning looks like and this looks a lot like it.
There is a significant distinction between "we've found a Dyson sphere" and "we've found an object that has the characteristics we would expect of a Dyson sphere".
I mean, if we have had breakthroughs in resolution and compute, and life really is everywhere, wouldn't it make sense that we would start finding these at some point? Why not right now?
I grow skeptical. Congruent planes of orbital accretion explain all this hype much better.
The flat planier elliptical orbits (and planetary rings) come by millions of years of settling down of the otherwise chaotic convergence of material that created their systems.
These readings that spark imaginations beyond science are yet chaotic systems (from whichever influence) that have not yet settled down (debre would be in irregular orbits.)
As sciencey as finding a wormhole off the shoulder of Europa.
> The flat planier elliptical orbits (and planetary rings) come by millions of years of settling down of the otherwise chaotic convergence of material that created their systems.
I thought all of these seven are estimated to be old stars which such processes should have long ago settled down.
There's lots of reasons an old solar system can become chaotic again, assuming it ever became nonchaotic. Anything with sufficient mass or energy passing near or through the solar system would cause a lot of chaos
To me, Dyson Spheres seem impractical. For one, where are you going to find all the material needed to cover even a fraction of the surface of a star? Additionally, if you do build something that massive, you'll probably influence the movement of the planets.
The term "Dyson Swarm" is preferred because it is a cloud of orbitals, not a rigid sphere. A rigid sphere was never the idea proposed (by Freeman Dyson). This idea comes from science fiction misunderstandings of the term "Sphere".
Think of a Dyson Swarm ("Sphere") as the water droplets in a fog. Collectively they absorb the light going through but the water droplets (and the orbitals) are relatively sparse. So a billion orbitals around our Sun at a distance Venus and Mars would still have a mean distance between them of over 100,000km.
So how much material do you need? One estimate I've seen for a billion such orbitals is less than 1% of the mass of Mercury. Why Mercury? Because it's metal-rich and its proximity to the Sun means energy is incredibly abundant and cheap.
That's to build billions of O'Neil Cylinders.
Even if you don't need that much living room, here's something else you can build: statites. That's a portmanteau of "static satellite". Instead of orbiting the star, they are so light that the solar wind is sufficient to counterbalance the gravity. These things would simply collect energy and/or just reduce the amount of solar energy hitting something like a planet (eg to cool the EArth).
I don't want to say they are practical, but for sure you would build them with planetary matter so you would influence the movement of planets as you would dismantle them. At the end you would not have any planets left.
You disassemble a planet for the raw materials. Mercury would do.
The real problem is that Dyson spheres are wasteful because stellar fusion is thermodynamically inefficient. If you harvest the material of the star and fuse it yourself, you can keep the lights on for trillions of years.
Interesting thought. I've never heard of this idea. Let's think it through.
If I understood correctly, you suggest to turn the heat from fusion into a usable form of energy. On earth we'd do that using steam turbines. Harvesting only the hydrogen from the star to bring it on a planet and fuse it in a reactor seems silly, as the hydrogen is already at sufficient temperature to fuse on its own. So we could send water and steam turbines close to the sun where the turbines charge some sort of battery? Perhaps on some super elliptic orbit, where we switch the full batteries with empty batteries at the apihelion.
You can keep it in the same orbit but spread the mass out along the orbit to the other side and that changes the combined CoG to be closer to Sun's CoG in turn changing Earth's orbit, albeit probably slightly
GPT4 seems to think it is a 3 body problem. Mercury and Earth are of similar size and exert gravitational effects on each other. Take away mercury and maybe the earth slowly drifts a little.
The point is that a very small difference in starting conditions yield wildly different results.
Interestingly, all of those supposed spheres are around dwarf stars, which make them inherently more practical for two reasons:
1) Much less material required
2) Much longer star lifespan (trillions of years rather than a handful of billions)
However, what's interesting is that those spheres all seem to be around red dwarf stars, which are much more active and shorter-lived than white dwarfs. They're just not as stable.
Our nearest neighbor, Proxima Centauri, is a violently active flare star -- and it's also a red dwarf with an estimated lifespan of ~4 trillion years.
But white dwarfs -- which are technically stellar remnants -- are indefinitely stable. They just keep cooling. It's surmised that they'll still be quite a lot warmer than the universe's background temperature in 10^15 years.
This has yet to be observed, but red dwarf stars, when they reach the end of their lifespan, should contract and become white dwarfs. It's said that our sun will also eventually end up as a white dwarf.
White dwarfs are superlatively stable, long-lived, and quite hot. And there are already quite a lot of them. If you're going to build a Dyson sphere/swarm, they're a very good choice. Though red dwarfs aren't bad...
If you are on the level to think about building a Dyson sphere, you are probably also able to create solid matter from the star's energy itself and the other matter floating around the star system. At that point, it's more a question of how long it takes, then how you do it.
I don't think the article and researchers meant it's actual rigid sphere, that's just the Star Trek based popular opinion. Dyson Sphere is Dyson Swarm, people just didn't get it the first time.
it can be super thin (compared to sun scale) so you wont need lots of material, like you dont need lots of gold to plate contacts. And as there is not a lot of mass there will be not a lot of influence on gravitational field.
The current total world-wide production of anti-protons in a period of a year is in the range of nanograms. Maybe we will never see a dyson sphere because all far advanced civilisations have antimatter reactors.
Of the swarm itself? If you gather the swarms orbital energy they will fall into the sun, because they won't be moving fast enough. So you'd need to propel them using more energy
1. Interstellar travel: people don't realize just how large the energy budgets are to get to even the nearest stars, even with pure matter-to-energy conversion. This is, of course, the theoretical upper limit of efficiency but we have nothing remotely close to it. Chemical rockets are complete nonstarter becasue of the mass of the fuel makes the entire thing nonviable, even in a theoretical sense, beyond a travel time of hundreds of thousands of years. Even then you need energy to survive so it's unclear if you have enough.
So what do you do? Well, if you can reach interstellar speeds without using fuel you've solved so many problems. How do you do that? You focus energy from the Sun onto effectively a solar sail. You still need to slow down at the other end but you get some of this for "free" with resistance from the interstellar medium.
2. Computers. Our ability to utilize extra computing power shouldn't be underestimated. One possibility is virtual worlds. One estimate I've seen is that you need about 10^15 operations/second to simulate a human brain. A Matrioshka Brain (basically a Dyson Swarm that's essentially a giant computer) gets to (IIRC) ~10^80 operations/second. AIs that are basically people could live an entire virtual existence.
3. Weapons. Basically, if you have a Dyson Swarm you could sterilize the galaxy in about 100,000 years if you wanted to with a so-called Nicoll-Dyson Beam. Or use relativistic kill missiles taht are just basically lumps of metal or rock at near light speed.
If human brains are proof you don’t need the energy of a star to do 10^15 operations/second, doesn’t that just mean our understanding of how to build efficient computers is very primitive?
A human brain consumes approximately 12 Watts. If 10^15 operations per second took 12 watts, 10^80 operations per second would take 10^39 W, which is several orders of magnitude beyond what all the stars in the visible universe combined produce.
Using all of the Sun's power at brain level energy efficiency would be equivalent to 10^40 operations per second. Still a quintillion times the combined brainpower of all humans currently alive.
If we look at what we use it for, it would probably to power some kind of cryptocurrency speculation scheme, or personal AI generation of ads for neural implants.
Imagine if a Type II civilization built a Dyson sphere around a star but a Type I civilization was on a nearby planet. Then again I guess at that point the Type I and III would be aware of each other. I wonder could the Type I planet stop the Type III civilization? The Type III would be like gods to the Type I's but the Type I's would be nothing more than a nuisance if even that to the Type IIIs.
When I was 10 (1988) reading Larry Niven's "Integral Trees" I was disappointed that the story didn't end - as I had expected it to - with the Carther descendants eventually building trees to entirely surround the star.
nah you can just create little holes in the sphere to illuminate the planets. negligible power loss. Earth and all the planets live on the sun's crumbs, no the (crumbs of the cumbs)^12
Good point. Since all our planets surround the sun more or less in the same plane, the dyson sphere could cover the remaining 95% of the sphere without affecting the planets too much. Remains the issue that you'd probably need the material of those planets to build the dyson sphere.
Looking for Dyson Spheres or "the Simulation" or any other highly speculative technology is anti-science. It is the opposite of evidence based. I am so sick of these non-science ideas being promulgated and given resources when there is plenty of actual science (evidence based) that needs funding.
Theories that are worth investigating should be based on past evidence. They should be attempts to explain things we have observed. If they aren't they are wild speculation, and as I said, anti-science.
Dyson sphere(swarm, because sphere is misconstrued as solid) is based entirely on known physics and can be made with our existing technology base, just not with our current industrial base.
I do not want to be living in your head. Why is searching the unknown with the tools at our disposal anti-science? Because it goes against some kind of norm held by what is deemed the "scientific community"? Who even is that and why do they get to say what knowledge to pursue?
I already explained. Evidence. Looking for the unknown does not necessitate looking for a specific highly speculative technology that there is zero evidence for and zero reason to believe exists other than it's a cool idea.
It is not really a speculative technology. A Dyson Swarm is doable within our existing technological base. If we are capable of building an artificial satellite, we can build a dyson swarm.
Baloney. We can not build one that is of any use. That is the speculative part of it. Inherent in looking for it is that it's an extremely worthwhile, nearly inevitable, idea. We have zero evidence for that.
We build satellites that look at our sun. That's one part of our dyson swarm. The beauty about a dyson swarm is that it can be built incrementally over time as we find new uses for space.
Ironically, if someone were to say "this is not science" in a thread about dark matter or string theory, they'd be upvoted.
My own take is that it's not science, but engineering, in the sense that it's based on already established scientific principles. It's more like a project proposal. The unknown is not whether it's physically possible, but whether we can find a civilization that has built one.
> Przybylski's observations indicated unusually low amounts of iron and nickel in the star's spectrum, but higher amounts of unusual elements such as strontium, holmium, niobium, scandium, yttrium, caesium, neodymium, praseodymium, thorium, ytterbium, and uranium.
While the explanation is likely some unknown natural process, salting a star with an impossible chemical composition might also be a way for a technological species to create a monument, correct? This seems like it would involve moving less mass around than a Dyson Sphere/Swarm, although it would need a constant feed, if I understand the situation correctly.
Astonishingly, there appears to be no contemporary analysis of this star.
[0] https://en.wikipedia.org/wiki/Przybylski%27s_Star
"The Star That Shouldn't Exist" - Prof. David Kipping
https://www.youtube.com/watch?v=maMDGZOD3mI
"Why is There Plutonium in This Star? Przybylski’s Star with David Kipping" - Event Horizon
https://www.youtube.com/watch?v=VUbjdaPy4mw