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Dyson sphere
- hedgehog 10y agohttps://en.wikipedia.org/wiki/Matrioshka_brain https://en.wikipedia.org/wiki/Matrioshka_brain
- kbenson 10y agoSince this is apparently what we're doing now, here's my move. ;) https://en.wikipedia.org/wiki/Computronium https://en.wikipedia.org/wiki/Computronium
- hedgehog 10y agoNice. I named our company after the Matrioshka brain in a roundabout way (http://1026labs.com http://1026labs.com, 10^26 being the wattage of our sun) but we haven't called anything computronium yet. Edit: We're on the way... http://www.theregister.co.uk/2016/07/25/semiconductor_industry_association_international_technology_roadmap_for_semiconductors/ http://www.theregister.co.uk/2016/07/25/semiconductor_indust...
- sehr 10y agoOT, but the Dyson Sphere was the first idea that gave me a deep sense of sadness knowing I'll never see it. How can you feel fulfilled laying the groundwork when things like this lay in store? And I'm just a software developer, I can't imagine how people in more relevant roles feel about it.
- deleted 10y ago[deleted]
- kbenson 10y agoThe other option, which is what I generally feel, is a sense of purpose that we need to make sure we shepherd the human race in the small way we can to the eventual goal of something like this. That is, it's engendered a bit more thoughtfulness about not just what policies yield the best current outcome, but what if we took a path of advancement slightly less optimized for current ease and happiness and more for future gain? We are of course very far from being able to correctly plan and carry out anything like that if we really wanted to, given that our current advancement is almost entirely directed by market forces and psychology that we are just beginning to understand, but it's an interesting thought experiment. Can you ethically deny X people currently for the betterment of n*x people in the future, assuming population growth and expansion? If so, what's to keep us from enslaving all the current people in pursuit of ultimate happiness of some theoretical future? If not, why are we saving anything for future generations rather than consuming it all for our benefit right now? The extremes are of course easy to answer, but the variables that go into it make it interesting to think about.
- boterock 10y agoI think that some day the humanity will grow too much and will get tired of overpopulation (I'd hope 30 billion would be the number, but if the humanity is arrogant, they would push it up to 100 billion or more), some people will just die because the planet can't provide enough resources, some rich people will buy other peoples live and kill them (give them a ton of money only if they are willing to die soon) and the world population will agree in not growing anymore but enjoying and preserving the planet as it is, maybe staying in a billion population. After that the world will start to restore and men will have to do nothing because machines are already doing everything, and the only jobs the humanity will have are going to be science and entertainment (incluiding arts and sports)... humanity will no longer grow not because they can't, but because they don't want.
- kbenson 10y agoThat assumes we are constrained to a single planet, and solar system. I'm not sure why once we have the ability to settle other planets and solar systems, why we would ever really be constrained by overpopulation prior to running up against some other constraint, such as another species.
- nilved 10y agoOur growing population will be constrained by resources long before we invent a way to colonize other planets.
- kbenson 10y agoWell, that's either a (relatively) short-term constraint, or we are no longer advancing. When talking in the context of Dyson spheres, I think that naturally puts the time frame at multiple orders of magnitude longer than any constraint should hold us back, unless we are actually regressing rather than advancing. Put another way, when talking about tens to hundreds of thousands of years in the future, I'm not sure even a thousand years from now to get even the most rudimentary of interstellar ships registers as more than a blip.
- kobeya 10y agoNot with that attitude you won't. What makes you so certain you will never live to see it? Be proactive and move your efforts to life extension and dependent technology.
- rbanffy 10y agoSeeing a Dyson sphere being built is some serious life extension. It probably involves lots of major discontinuities and full medium changes.
- geofft 10y agoYou can see the manned space program. If you're under 43, there's a decent change you'll never see a human leave Earth because you were born too late. Countless humans died before either of these. You'll always be born too early for some things, and too late for others. What's exciting to me is what lays in store tomorrow, next year, next decade. Next century is someone else's territory, but mine is so vast I have no reason to be jealous of them.
- imron 10y agoPlenty of people still leave earth, they just don't go to other planetary bodies. Hopefully Elon Musk will come through.
- zombees 10y agoIf all the dimming star headlines are piquing your interest, you must read Pandora's Star and Judas Unchained by Alexander Hamilton. It's about the same event being observed but a couple hundred years from now in a post FTL society, so naturally they have to wander out and see what's up. The pair is one of the best recent science fiction stories to come out in the past 15 years.
- siquick 10y agoGonna check it out, thanks.
- imron 10y agoCame here to suggest this. Pandora's Star is an excellent (albeit long) read. Note however, the author is Peter F. Hamilton.
- 13of40 10y agoJust bought it on Audible, and apparently it's 37 hours long...
- kchoudhu 10y agoYeah, Hamilton really gets into world building. Often to the detriment of actual storytelling -- which on its day, is actually quite good. I'd still recommend these books though. Edit to add: Hamilton also wrote The Void Trilogy, set in the same universe as The Commonwealth Saga. They're interesting, but less so than the Commonwealth books.
- jamie_ca 10y agoRecently read it on my phone, which tells me it took 27.4 hours, or about the same as Scott Lynch's first two Gentlemen Bastards novels (also a good read, for different reasons), or a bit longer than the first 4 Dresden Files.
- zombees 10y agoLast time I write stuff while tired...
- lossolo 10y agoI learned what Dyson sphere is as by product of reading this by Bruce Scheiner, really great read: " One of the consequences of the second law of thermodynamics is that a certain amount of energy is necessary to represent information. To record a single bit by changing the state of a system requires an amount of energy no less than kT, where T is the absolute temperature of the system and k is the Boltzman constant. (Stick with me; the physics lesson is almost over.) Given that k = 1.38×10-16 erg/°Kelvin, and that the ambient temperature of the universe is 3.2°Kelvin, an ideal computer running at 3.2°K would consume 4.4×10-16 ergs every time it set or cleared a bit. To run a computer any colder than the cosmic background radiation would require extra energy to run a heat pump. Now, the annual energy output of our sun is about 1.21×1041 ergs. This is enough to power about 2.7×1056 single bit changes on our ideal computer; enough state changes to put a 187-bit counter through all its values. If we built a Dyson sphere around the sun and captured all its energy for 32 years, without any loss, we could power a computer to count up to 2192. Of course, it wouldn’t have the energy left over to perform any useful calculations with this counter. But that’s just one star, and a measly one at that. A typical supernova releases something like 1051 ergs. (About a hundred times as much energy would be released in the form of neutrinos, but let them go for now.) If all of this energy could be channeled into a single orgy of computation, a 219-bit counter could be cycled through all of its states. These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be unfeasible until computers are built from something other than matter and occupy something other than space."
- Franciscouzo 10y agoHow would counting with Gray code [1] change the math? [1] https://en.wikipedia.org/wiki/Gray_code https://en.wikipedia.org/wiki/Gray_code
- tromp 10y agoIt changes things by a factor of 2, since a Gray code increment flips exactly one bit, while a regular binary increment flips 2 bits on average. That's ignoring all the logic required to figure out exactly which bits to flip...
- dysob 10y agoWhy not a Dyson-like moon coverage which allows us to regulate the night and day illumination provided by our celestial satellite? Solar operated mirrors whose focus and intensity can be regulated remotely.
- grabcocque 10y agoUnlike other speheres it's made from transparent plastic and doesn't lose suction.
- jessaustin 10y ago...and it costs $500.
- deleted 10y ago[deleted]
- dexwiz 10y agoI was obsessed with the idea of dyson spheres when I was younger. The are the alternate path of an advanced civilization besides exploring the stars. You probably wouldn't want to build one around our Sun, since it will eventually expand, and cook anything inside the sphere. Building the sphere would likely take millennia, and there is no reason to invest in building around a start that will eat it. Instead you would build it around a red or white dwarf. These are stable for billions or trillions of years. Meaning you could build a dyson sphere, and live on it until the end of the universe as we know it (Stelliferous era). Red dwarfs are much less massive than our star, so you could build a smaller sphere (still relatively huge), and material property requirements would be less. White dwarfs are a bit more massive on average, but will last much longer. Dyson spheres, bubbles, rings, whatever would not experience a day/night cycle. So would either have to build it out of a material that passively radiates excess energy out the other side, while maintaining habitable temperature. Or you build a second set of smaller rings or disks that orbit closer to the star at a different rate. The inner set casts shadows on the outer set, simulating a day/night cycle. Successfully building a dyson sphere would likely only be done to either power a FTL gate of some sort or a giant computer. If you built a computer to simulate a universe, and properly managed the inner star's output and lifecycle, you could feasibly escape the end of the universe by simulating a smaller one for yourself.
- saalweachter 10y agoFreeman Dyson actually had another way to escape the heat death of the universe: by taking advantage of it. As the universe cools, the noise of the background radiation will diminish. Dyson posits that this would allow us to build an analog computer which uses less and less energy as time goes on-- it could run forever on a finite store of energy. So even if the universe "ends", we might be able to build a computer which doesn't.
- vollmond 10y agoCan you recommend any reading on this? Sounds interesting.
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- foobarbecue 10y agohttps://www.youtube.com/watch?v=AS_fiyKkAno https://www.youtube.com/watch?v=AS_fiyKkAno
- pascal1usa 10y agoCan someone please build one of these around SF. We desperately need it. ;)
- jcbeard 10y agoWow, did nobody watch Star Trek TNG? I learned about them when I was about 10 watching the Relics episode (https://en.wikipedia.org/wiki/Relics_(Star_Trek:_The_Next_Generation) https://en.wikipedia.org/wiki/Relics_(Star_Trek:_The_Next_Ge..., or amazon prime: https://www.amazon.com/Relics/dp/B00R143VHC/ref=sr_1_1?ie=UTF8&qid=1470789546&sr=8-1&keywords=star+trek%2C+tng%2C+relics https://www.amazon.com/Relics/dp/B00R143VHC/ref=sr_1_1?ie=UT...). Very cool concept.
- morganvachon 10y agoYep, that was an awesome episode for what it was, and the novel that served as a sequel was great as well. Unfortunately the version of a Dyson sphere depicted in both is completely untenable, according to Freeman Dyson himself. He reportedly enjoyed the episode as "a piece of cinema" but denounced the science involved as 100% fiction and not possible. As others have said, perhaps building something like that around a dwarf star would be within the realm of possibility, but you still have issues such as radiation, constant daylight, gravity, and drift (the sphere would eventually drift into the star since it's not actually orbiting and is much more massive than even a large planet). Still, it's a really cool idea and a fun thought experiment.
- jcbeard 10y agoExactly, most science fiction representations fail on the engineering test. That' snot to say that some future change in our understanding of physics might not change what is in fact possible. One reason I love scifi is that the authors/readers/watchers are free to drop the need to be fully grounded and go for something truly cool. I suspect what we view as totally impossible today, might be within the realm of possible 2-3k years from now.
- morganvachon 10y agoYep, how does the saying go? Any sufficiently advanced technology will be indistinguishable from magic when presented to a less advanced society.
- deleted 10y ago
- SubiculumCode 10y agodysonspheres are cool, real cool, but how does the dyson sphere wikipedia page get to the front page of hacker news?
- detaro 10y agoa bunch of people thinking "hey, dysonspheres are really cool" -> * upvote *?
- kevin_thibedeau 10y agoPeople are speculating about alien megastructures around Tabby's star. That's why.
- mcv 10y ago> dysonspheres are cool, real coo If they capture all their sun's energy, shouldn't they get pretty hot? That's the thing with Tabby's Star. If there really is a Dyson Sphere under construction blocking all that light, shouldn't we be seeing a bump in infrared with the same amount of energy as the blocked light? Unless their Dyson Sphere-constructing super tech has found another way to get rid of the heat, of course.
- SubiculumCode 10y agoisnt a dyson ring good enough?
- thatswrong0 10y agoGood enough for what? If we're talking about providing for the energy needs of the Earth, that'd be way way overkill too. See how much solar we'd need on Earth to power our needs: http://www.techinsider.io/map-shows-solar-panels-to-power-the-earth-2015-9 http://www.techinsider.io/map-shows-solar-panels-to-power-th... If we're talking about powering some future hypothetical civilization.. Yeah it'd have to be ginormous and have huge energy requirements to warrant that much energy. Maybe if they wanted to channel that energy and blow up a few planets it could be useful..
- majewsky 10y ago> to power our needs Demand follows supply.
- veli_joza 10y agoBuilding the ring would be interesting engineering challenge. Once you build it with sun in its center of mass, it's in unstable equilibrium, so you only need to compensate for the drift. But until it is built, your components have to orbit the sun. So the finished ring would also keep this momentum and it would be rotating around its center.
- powertower 10y agoThere are other more plausible options for these civilizations then building absolutely gigantic structures around suns. 1. Build devices/objects (https://i.ytimg.com/vi/bQ7RaOMHb5I/maxresdefault.jpg https://i.ytimg.com/vi/bQ7RaOMHb5I/maxresdefault.jpg) that are able to get close to the stars, that would then absorb the emitted energy from the various coronal ejections, magnetic fluxes, etc. 2. There is more energy in the fabric of empty space-time than anywhere else. An advanced civilization would likely be able to harvest this ZPE (zero point energy or field) using rather small devices.
- triplesec 10y agoFor an evolution of the Dyson sphere in fiction, read (Free online) Charles Stross's Accelerando, a novel of 9 connected Singularity-oriented stories. http://www.antipope.org/charlie/blog-static/fiction/accelerando/accelerando-intro.html http://www.antipope.org/charlie/blog-static/fiction/accelera... For those who don't know him, he used to be a professional programmer, and he's a very smart writer, lives and his blog is here. http://www.antipope.org/charlie/ http://www.antipope.org/charlie/
- rbanffy 10y agoHe's also seen here occasionally as cstross.
- TheOtherHobbes 10y agoI can imagine a Dyson Swarm, although intuitively I wouldn't be surprised if there's some kind of computational limit created by the fact that the bigger a swarm gets, the more computation is needed to keep it gravitationally stable But I think a Dyson Sphere - something as solid as a planet, but with a radius the size of a planetary orbit - is physically impossible, even with unimagined magic alien super-materials. The physical configuration of a Dyson sphere is inherently unstable. It's the astronomical equivalent of balancing a pencil on its tip. Any asymmetry at all - including proper motion and radiational asymmetry from the star - would need active correction. Without it, the entire structure will fall apart catastrophically. (It might take a while, but there's not much point building something that big unless it lasts.) Active correction implies movement, which is not what you want on an inhabitable surface, or even on a computing machine. And it probably wouldn't be much use as a computing machine. The bigger the system, the longer it takes information to propagate across it. A system with propagation delays on the order of minutes isn't going to run nearly as fast as its energy budget might suggest. That's still true even if you imagine some kind of ultimate limit system where the computation happens directly on a spherical spacetime shell instead of on tangible hardware. I suppose it's possible that if it turns out that KIC 8462852 is showing evidence of alien action, the aliens are somehow dimming the star directly instead of by building screens around it.
- fizx 10y ago> The physical configuration of a Dyson sphere is inherently unstable. It's the astronomical equivalent of balancing a pencil on its tip. No, it's neutral--the equivalent of keeping a ball on a table.
- traviscj 10y agoNo. Consider a small perturbation (i.e. Poking) the ball on your table. At least for a small enough poke and/or a big enough table, friction slows down the ball again, and it stops. Now consider a small poke on a Dyson sphere that was (before the poke) perfectly balanced. The part that got poked is slightly closer to the sun, and the point opposite is slightly further away. So the closer part has some gravitational force acting on it, and the opposite part has a lower gravitational force acting on it: O(1/(r-e)^2) vs O(1/(r+e)^2). The imbalance causes a net gravitational force in the direction of the poke, which eventually crashes into the sun.
- jlebrech 10y agoA variation on this and the first rung of he Dyson swarm would be a space station that follows the earth's orbit rather than orbits it. you could call it a dyson tile or fly or something like that.
- rbanffy 10y agoOne issue of ring worlds is traction (and Dyson spheres are much more complicated than that). Nothing we can imagine and certainly nothing we can build can take it but what if instead of rotating it above orbital speed to create gravity inside the ring we rotate it below orbital speed, create gravity on the outer surface and rely on materials that can withstand the compression? Sunlight could still be reflected by a fleet of orbiting mirrors that wouldn't orbit the star in sync with the ring and thus would not be subjected to the structural forces of the ring. In case the ring is built around a smaller star with a spectral emission very different from the one preferred by the ring builders, the mirrors could adjust that too.
- powmonk 10y ago> create gravity on the outer surface That's a tricky one. Do you mean make the ring thick enough that it has enough mass to have its own gravity?
- rbanffy 10y agoNo. When the ring rotates at orbital speed, there is no perceived gravity on either side. If the ring rotates faster than that, one would perceive a force pulling them away from the central star. If, however, the ring rotates below orbital speed its mass would be pulled toward the central star (along with anyone standing on its outer surface). The forces pulling it towards the star would compress its structure (the opposite of the traction forces a faster ring with positive gravity on the inner surface would experience). I think (I haven't checked the numbers) the ring's mass can't be neglected, but, because of the shape, it'd act as an extra mass within the central star. The ring is, in fact, in its own orbit.
- rbanffy 10y agoGood and bad news. A stationary ring around a star with one solar mass would be very close, about a tenth of the distance Mercury orbits the sun, to make its inhabitants experience one Earth gravity on its outer surface. The good news is the ring would be much smaller than 1AU and it'd be easier to do it around a large white dwarf and still get a lot of energy from it. Not sure how much pressure solar wind would be, but, if the star is active enough, we could use it to partly sustain the ring structure.