Civilizations at the End of Time: Black Hole Farming

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Today’s topic, Black hole Farming, is going to be a difficult one because it’s a video I probably shouldn’t have made without covering other topics first, and also because it draws heavily on quite a few other videos I did make first. So it essentially amounts to three topics that we need to cover today and assumes a knowledge of the most recent videos on the channel, which means that if this is your first visit to this channel, while I normally try to make videos as standalone as possible and you probably can watch this without watching the others first, it isn’t advised. That said, it isn’t absolutely necessary and to help with that, whenever I bring up topics we’ve covered in more detail in other videos you will usually see an in-video link for that video pop up, and you can just click on it to pause this video and watch that one. You can also turn on the closed caption subtitles if you are having problems understanding me. So I said it was actually three topics, not just one, for today. What are those three topics? Well let’s list them out. 1) Using Black Holes for Power Sources We’ve talked about this before but mostly in the context of Hawking Radiation from small, artificial black holes. Today’s video is focused on large, long-lived black holes, where Hawking Radiation is incredibly tiny and other methods are needed. So we’ll be discussing those other methods as well as what the implications of living on minimal Hawking Radiation would be like 2) The Fate of the Universe In this section we’ll go over the timeline of ages of the Universe fairly quickly, and also quickly cover some of the other ideas for Civilizations far in the future, which we may expand on in future videos. 3) Black Hole Farming In the last section we’ll get into the meat of things, trying to contemplate what civilizations would be like that essentially fed themselves off black holes. It’s the concept of using black holes as the power source for your civilization, and actually creating or placing black holes to make that work best, which is the origin of the title. I think it summons to mind the image of farmer in coveralls with a pitchfork literally farming black holes but we’re sticking with it anyway. So without further ado, let’s dig in. Our first topic, using Black Holes as power sources is, as I mentioned, something we looked at before in the twin videos discussing Hawking Radiation, Micro-Black Holes, and using them to power starships. You may want to watch those, or re-watch those, before proceeding, but the quick summary is that Black Holes are thought to emit Hawking Radiation loosely in proportion to their size. Except backwards from what you’d expect, the giant monster sized ones in the centers of galaxies emit so little of it you’d need a trillion, trillion years to collect enough energy to turn on a little LED light for a fraction of a second. Alternatively the small ones gush out power so fast they burn out their tiny mass in very short times. There’s two upshots of this. First, that the lifespan of black holes is proportional to the cube of the mass, one twice as massive emits only a quarter of the power and lives eight times longer, one ten times as massive emits a hundredth of the power and lives a thousand times as long, etc. Second, if we can make artificial black holes, and especially if we can feed matter into them to replace what they lose to Hawking Radiation, we have an excellent power source for things. Black Holes are roughly on par with anti-matter, and vastly better than nuclear fission or fusion, in terms of energy per unit-mass of fuel, and they don’t blow up unless you starve them to death, a process that would take years or centuries normally, making them a very attractive option for power generation and storage. This is assuming we can figure out how to make small ones and feed them, both of which are actually a lot harder than with their bigger, naturally occurring kindred. Which again emit virtually no energy on timelines that can be measured without using scientific notation. This doesn’t mean we can’t tap black holes for power in other ways though. The preferred way to tap a black hole for power quickly, which also works on neutron stars, is to suck out their rotational energy. Stars spin, same as planets, they have a lot of angular momentum and that is one of those conserved quantities in nature. When they die and collapse they start spinning much faster for the same reason an ice skater twirling around with her arms out will spin much faster by just bringing her arms in toward her body. Our sun rotates around once a month, neutrons stars often rotate many times a second, that is why pulsars make such handy clocks. I was going to say pulsars are a type of neutron star but all neutron stars begin as pulsars, it’s just they have to be pointing in our direction for us to notice the pulsing and that effect diminishes with time. This isn’t a video on pulsars so I’ll just simplify it for the moment by saying they emit two narrow beams from opposite directions and if you’re at the right angle each of those beams will pass over you every time it spins around, which again is many times a second. They only do this for the first hundred or so million years of their life, and only about a tenth happen to line up with Earth so it is right to think of pulsars as a type of neutron star it’s just that the type is A) Fairly young and B) coincidentally aimed our way. Every neutron star was a pulsar for someone at some point. Science fiction loves to say you can use pulsars to get navigational fixes off of, and that’s basically true, but you’d need a catalog of all the young neutron stars to do that properly. And again it is only young neutrons stars you can use for this as they slowly lose energy and cool with time, something we’ll discuss a bit more in the second section of this video. Anyway needless to say black holes spin too, and very quickly, and both them and neutron stars emit huge magnetic fields as a result, same as Earth does from having a giant molten ball of spinning metal in the core. You can tap that power, sucking energy from spinning magnets was how the first electric generator worked, the Faraday Disc, which was the precursor of dynamos. The disc slowed down as it leaked power as electricity. Stealing away that black holes rotational energy, which is a large chunk of it’s total mass energy, is thus a pretty attractive option. And there’s various proposed ways of doing that. The Penrose process is probably the best known of them, and relies on being able to remove that energy because a black holes rotational energy is thought to be stored just outside the event horizon in what’s called the ergosphere. You obviously can’t dip under an event horizon and suck energy out, but we can from the ergosphere. There’s also the Blandford–Znajek process which is one of the lead candidates for explaining how quasars are powered. If you’re familiar with Quasars, and how they are brighter than most galaxies, this gives you an idea how much juice a black hole can provide. It also taps the Ergopshere for power and does it by using an accretion disc, so you’d use this on a black hole that already had one or that you were feeding, we’ll come back to that in a moment. You can also just dump matter into a black hole, it gains kinetic energy as it falls down, same as if we drop a rock off a tall building. If you tied a spool of thread to that rock and ran an axle through the spool attached to an electric generator you’d get electricity. And you could do the same with a black hole too. Of course if you drop that rock off the building you’d get less power than you’d expect because the rock is falling through air, slamming into air particles, and transferring much of its momentum to them, actually heating the air up in the process. This is how parachutes work, transferring all that kinetic energy into a wide swath of air as heat. It’s not a lot, but if the object is moving fast enough, like a spacecraft on re-entry, it’s a lot more and can make the object and the air it’s hitting so hot it will glow. You could gain some power with a solar panel that was nearby, drinking in that light. And you can do the same with a black hole because as matter falls towards them and often ends up in orbit around the black hole rather than directly entering, it forms what we call an accretion disk. And those glow quite brightly, giving off a lot of photons you can collect to use for power. If you dump matter into a black hole you can collect that power. It should be noted that when things approach large masses they usually don’t curve and slam down into them, and that’s as true for black holes as anything else. Their path curves, depending on how close they get and how massive they are. If they are very close to a very large mass they will hook right in, but normally they either fly off at a different angle or enter an orbit. And if there’s other stuff hanging around there for them to bump into their orbit will decay and they’ll eventually fall in. All that bumping, again, generates heat and if there’s enough heat, lots of visible light too, same as a red hot chunk of metal. That’s an accretion disc, for a black hole. And everything that falls into a black hole will add to its rotational energy too, though if it goes in backwards it will subtract from it. So if you’re dumping matter into black holes it pays to drop it in the right direction. Now neither the rock on a string or the solar panels collecting light off matter dumped into a black hole is terribly efficient as these things go, but they are a lot conceptually easier for some then the other methods I mentioned. Getting back to the Blandford–Znajek process, which I said was a prime candidate for how Quasars work and another black hole power method, and for our purposes it’s pretty similar to the penrose mechanism but happens to have an equation you can use to determine how much power you get out of the thing. They aren’t the same thing, and if you want to explore the difference I’ll attach a link in the video description to Serguei Komissarov’s 2008 paper that detailed the differences for those who are interested. That equation shows us that the power output of a black hole via this process goes with the square of the magnetic field strength of the accretion disc and the square of the Schwarzchild radius of the black hole, both of which will rise if we increase the size of that accretion disc or if we increase the mass of the black hole, and in nature bigger black holes usually have much larger accretion discs. Particularly the big ones near the center of galaxies, especially volatile young galaxies, as I mentioned this is usually considered a prime candidate for how quasars are powered and quasars frequently give off a hundred times the power of an entire regular galaxy. We would presumably want to tap that power a lot slower, using much smaller black holes and matter flow rates. Now any of the methods that involve extracting rotational energy will eventually cause that black hole to slow and finally stop rotating. At that point while you can still dump matter in, you won’t get nearly as a good a return, and the black holes mass will increase, making it live longer and give off less power via Hawking Radiation, which is the only option I’m familiar with that let’s you tap into the rest of that mass energy, as the black hole slowly evaporates. And we do want that energy. While lighter artificial black holes can emit useful sources of power via Hawking Radiation, the big massive ones essentially aren’t. Not unless you can build ridiculously sturdy equipment that can operate without wear or tear needing power or replacement matter to fix over even more ridiculously long periods of time. But we will have at least a hundred trillion years to get better at building sturdy material, and there aren’t many things around to cause external wear and tear by then, and it is the only game in town after you suck out the rotational energy and all the stars burn out, plus if you can do it there are some big potential advantages to waiting that long to pull out your energy, as we’ll discuss in part three. But first, let’s hit Part Two and review the Fate and Chronology of the Universe. Or I should say the primary current theory for a naturally aging and expanding universe. I mention that for two reasons. First that theory could be wrong, it probably is at least in part, or incomplete, and second because we don’t live in a universe that’s likely to continue along a natural path, because we live in it. Intelligent critters can change their environment after all, and generally tend to, and we’ve spent a lot of time on this channel talking about ways to tinker with planets, stars, and whole galaxies so it would seem silly to ignore how that could affect the progression of the Universe. So first we have the big bang, which doesn’t terribly interest us today, other than it being worth keeping in mind that the Universe began expanding then and continues to do so, and almost certainly has parts that are so far away from us that we will never detect any light from them since new space emerges between them and us faster than light can cover the distance. This effect will only get worse with time and eventually only the galaxies in our local area close enough to be bound to us by gravity will remain. As those galaxies get further away, and from all that emerging extra space seem to get further away faster and faster, the light from them red shifts and gets weaker and weaker. That’s not the only red-shifting light out there though, and there’s one type that is of great interest to us today for our final section. The Big Bang happened about 14 billion years ago, and just 400,000 years later an event called the last scattering took place. Not a long time, an eyeblink compared to the age of the Universe, but still a hundred times longer than recorded history and about the duration of human existence. The last scattering was an important event, and is aptly named. Up until then the universe was a much smaller and denser place. And small and dense means hot. Very hot, up until then the universe would have glowed like a star in every single direction you look, a big white haze. But the light emitted didn’t go far because it was too hot for atoms to form yet and it that pre-atomic plasma soup light scattered much easier. As the universe cooled down and suddenly atoms could form, and were further apart from expansion, photons could suddenly travel long distance without being likely to run into anything and that kept plummeting. Most photons will never run into anything now. As a result there are always photons left over from then still flying through space thus far uninterrupted in their journey. Now when they started off the spectrum was pretty similar to what stars emit, visible light, but over time as they’ve traveled, with new bits of space emerging along their path red-shifting them, they’ve lost power. They went through infrared and finally entered the microwave range just recently, this left over radiation that’s in the background of everything throughout the cosmos, is called cosmic microwave background radiation. As more time passes it will grow weaker and weaker and the universe will keep expanding and cooling. Eventually it will get so weak and cold that those bigger naturally occurring black holes will finally start giving off more Hawking Radiation then they absorb in background radiation and actually begin to slowly age. Right now all naturally occurring black holes are actually growing in mass, even if there’s no matter nearby to feed them. That time, when things are that cold, is a long, long way off. Before we get there we have our own sun slowly getting hotter until it eventually renders Earth uninhabitable and goes Red giant, swallowing Earth, then leaves behind a earth-sized dense corpse called a white dwarf, which generates no new energy from fusion but still gives off a lot of light compared to what our planet uses, and ought to still be warm enough to light many earths for even longer than its current remaining lifetime before going red giant. That’s our first example of a civilization at the end of time, because normally we figure it’s the end of the road when our star goes red giant, at least here on Earth, and sooner than that too because the Sun is heating up and Earth will probably be uninhabitable inside a billion years. Except it won’t be, because there are intelligent critters on it. We may come back and explore this idea in more detail in the future but for now I want to use it as our first example of how you can’t look at the timeline for the natural Universe as particularly likely. Not because the science is wrong but because it doesn’t contemplate the impact of us on that timeline. We’ve talked a lot about moving planets or shielding them from light to cool them down. We looked at that in the terraforming video and more recently in the Ecumenopolis video. So a billion years from now without intelligence Earth might be rendered uninhabitable by a sun growing hotter, but that probably won’t be how it goes down. We might sterilize our planet ourselves long before that, our track record when it comes to screwing up our planet on accident or blowing up chunks of it is not in my opinion quite as terrible as many naysayers think, but it certainly isn’t anything we’d want to brag about either. Or we might disassemble it for building material. In the megastructures series we’ve explored the basic idea that a planet, in terms of living area, is basically as efficient as mountain with a few caves on it is. You get a lot more space by disassembling that planet to build megastructures, in the same way you would disassembling a mountain and its few cramped caves to use the rock and metal to build skyscrapers. You could disassemble the average mountain, and it’s cramped few caves able to hold maybe a few hundred people, and build housing for the entire planet. Similarly you can disassemble a planet and reassemble it as megastructures with thousands or millions of times the living area. So we might do that and have no planet here in a billion years. Or we could shade the planet, putting a large thin shade between us and the sun, decreasing the light we got, especially the infrared range that’s pretty useless for plants, and keeping us from burning up. Or we could just move the planet outwards. Moving planets is pretty time consuming as we discussed in the Terraforming video but it is doable, requires no advanced technology, and we do have a billion years. So in a billion years it would seem very unlikely the world will die, because it either will have long before from us screwing up or using it for building material, or because we valued it a lot and decided to preserve it. And you can protect against red giant phase of a star and weather it and come back in to live around that white dwarf remnant for many billions of more years. Of course even thirty billion years from now when that white dwarf is too cold to be of any further use to us, a black dwarf, the Universe will still be quite young and going full tilt. Our galaxy will still be forming stars at the same rate as now, only a bit faster since we will have merged with the Andromeda galaxy by then and some of our other neighboring galaxies will have either merged in by then or be approaching. It won’t be for 800 billion years, about 200 times the age of Earth and 60 times the age of the Universe, and 200 million times the duration of recorded human history, before that star formation starts dying off, and it will be an estimated 100 trillion years before it ceases entirely. There are stars that live longer than a trillion years and will still be around when star formation begins to ebb off, and they are more efficient at burning their hydrogen into helium too, and we may look at some examples in the future of how creating stars or intentionally storing hydrogen in artificial gas giant or brown dwarfs might be used to similarly extend the lifespan of the star-forming age of the Universe. Or to create essentially compact dyson spheres of high-efficiency, ultra long lived stars in what’s been dubbed a ‘Red Globular Galaxy’, a sort of massive megastructure light years across that hangs on the edge of being a black hole even though it’s not very dense. To the best of my knowledge that’s the largest continuous megastructure you can build, though I might be biased on it since it was my brainchild. Still we get stars for 100 trillion years, and actually still some after that since even though the universe will be composed of nothing but brown dwarves, white dwarves, black dwarves, neutron stars, and black holes they will occasionally run into each other. And a white dwarf merging with a brown dwarf could form a new star as hydrogen is added to that stellar remnant, though if it is added to fast you get a Nova instead, a very common event in nature that never seems to get any mention compared to its more spectacular big brother the supernova. And the collision of dead stars is a common cause of supernovae. A whole lot of hydrogen hitting a white dwarf or a neutron star or two of them slamming into each other, is quite common, since many stars are binaries and the bigger of the pair will go red giant and expand to include its neighbor and cause that star’s orbit to decay, just like an accretion disc, until they run into each other. So it’s not just the explosion given off when a big star dies. Kinda like the misimpression that pulsars are a particular type of neutron star, I think popular science and science fiction has tended to make folks think supernova is synonymous with big giant star dying and nothing else. But that universe, at the 100 trillion year mark, will be pretty dark and cold, and just keep getting more so. By then the other galaxies will all have either folded into our own or fled over the cosmological event horizon never to be seen again long ago. We’ll still see light coming from them forever, but it will keep red shifting to be weaker and weaker. But we won’t be able to talk to them anymore or them talk to us, the signal lag will keep getting longer and longer until it becomes infinite, and that will happen a lot sooner than the stars burning out, indeed it’s pretty much constantly happening all the time. The Universe keep expanding in size but the Observable Universe, which also keeps expanding in size, is constantly hemorrhaging mass over the horizon. Most of the galaxies that aren’t close enough to us to be gravitationally bound but close enough to be reached without faster than light travel could conceivably be colonized over the billions and trillions of years to come, by us, or might host alien life forms we might exchange long, very delayed, cordial talk with. So I nickname this phase the ‘Long Good Bye’, because all the civilizations around will presumably be emitting their history and commentary on life constantly and one by one the furthest ones away will disappear, and you from them, and you’d know when it was coming so you could send out one last message to them. It probably would be cordial chat, and thus probably a sad goodbye, since if you haven’t invented some form of faster than light travel by then it’s not like you have anything to fight over since you can’t. I don’t think even the most determined warmonger will spend a billion years flying off to do war with someone. And it would seem if you haven’t figured out how to go faster than light by then, or beat entropy, that you might as well settle in for the end. Though as we’ll see it doesn’t have to be the end and the speed of light actually becomes an increasingly smaller hindrance as time rolls on, even though the Universe keeps getting bigger. So on to part three, black hole farming. The Universe is a hundred trillion years old, and now you are living on reserves of hydrogen you’ve collected to either run in artificial fusion reactors or make new stars from. Or to feed into dead stars for a bit more power as you collect their slowly decreasing heat and light. Or your artificial small black holes are running out of fuel if you’ve got them. Now you can tap all those black holes for their rotational energy and live on that for a good long time. You can slam dead stars together to make more and live on those too. But eventually they also run out of rotational energy. 100 Trillion years is usually the timeframe given for the end of life, effectively the end of civilization. The point at which the handful of folks still remaining show up around the last star and have a party at the restaurant at the end of the Universe, but we could ration it out a lot longer using those techniques we’ve discussed thus far. You can even stick black holes near each other and suck power off their orbital decay and merger. It does eventually run out though. Now all that’s left is Hawking Radiation. And I’d have to conclude this pretty much has to be the end of biological life in favor of minds that simply exist on computers running in virtual landscapes. From a practical perspective this is probably irrelevant since you can still have all your planets and architecture and art and fashion and so on inside those virtual landscapes. We talked about this sort of concept in the Transhumanism and Immortality video and if the idea of living in a computer feels off to you it might be better to watch that now or when you’re done with this video. We used that to jump into the Doomsday Argument and Simulation Hypothesis videos too. In the context of the Doomsday Argument and Simulation Hypothesis as we’ll see in a bit when we examine the sheer immensity of these constructs in time, odds could be considered pretty good you and I are actually in one of these setups, running on computers around a black hole in a dark old universe and we just don’t know it because whoever put us in there, which might have been ourselves, found it depressing to think about how they were on a ticking clock edging toward infinity and it was evening not morning, so they erased their memory of that. We will see shortly that these post-stellar civilizations could actually be where the majority of living in this Universe occurs, with the stellar phase just being a quick bright blip against the sea of eternity, but even they run out of juice in the end and probably have to start sacking their stored memories to keep going just a while longer and it’s not hard to imagine the ones near the end might decide they’d be happier without being aware they were doing that and opt to replicate those last eras of Old Earth long gone but not forgotten. Anyway odds are good biological life is a long ago thing of the past, I mean it’s been trillions of years and as we saw in the Matrioshka Brains video and Existential Crisis Series, you can get a lot more thinking power out of digital people running on computers than on food and air. But you can also do two other things with such digital people. First you can slow down their sense of subjective time. We normally talk about speeding it up, just taking a whole brain emulation of a person and running them faster than normal so they might experience whole years in minutes, but when you’re low on power you can just slow everyone’s subjective time down instead. And there’s not much point in hanging around at real time to watch the Universe since its black and boring now. But there’s two reasons you might want to start that rationing of time and energy a lot sooner, that form the first upside of purely digital people. One is a touch mundane, if you’ve got the remnants of our galaxies and its neighbors hanging out around a few million black holes hundreds or thousands of light years apart from each other, messages take hundreds or thousands of years to get back and forth. If you’re running at one thousandth your normal speed, conserving power, those message takes only months or years to arrive, and if you’re running at a billionth your normal speed you could have a phone conversation with someone on the other side of the dead galaxy without noticing a time lag. So the speed of light is finally beat by simple irrelevancy. You can’t exceed it but it’s now so fast compared to your experience of time that it simply doesn’t matter. The other upside I mentioned in the Matrioshka Brains video, and relates to the Universe getting colder. Currently we use a lot of power to flip a bit, as it were, to perform one single calculation, and there’s a little bit of heat generated, or a little power expended, every time you do that. We try to get better and better at making that amount smaller and smaller, and we may one day even figure out how to make it zero, through reversible computing, though that would seem to violate thermodynamics at least if you were doing anything that might qualify as thinking with it. It can’t be ruled out as an option but we are bypassing reversible computing or any specific discussion of quantum computing today, too many topics, too little time. The current theoretical limit is the Landauer limit, and it is considered to be the absolute minimum energy needed to erase a bit of data, essentially your minimum unit of thought. It happens to be linear to temperature, so if you can get that to be the maximum on your computing you get more computing – more thinking and more lifetime – out of every joule of energy you have. So as the universe cools you still have the same energy or power available but you get more thinking for every joule, and this setups a very different scenario and dynamic for the end of the Universe, if this limit becomes the control factor on things. Right now you and I, as basically 100 watt space heaters, get 1 second of thought for one hundred joules of energy, or 10 milliseconds of thought per joule. In fact it’s a lot less than that since we basically use most of our planet, and its nearly 200 billion megawatts of solar illumination to support 7 billion people and would have a rough time doing more than 20 billion off that without using the methods we discussed in the Arcology and Ecumenpolis video. So in terms of sunlight converted to food converted to thought we use around 10 megawatts of power to produce a second of human thought and arguably a billion times more than that since Earth only absorbs about a billionth of the sun’s light. But as we saw in Matrioshka Brains you could run trillions of trillions of trillions of real time human brain emulations. We found in the Transhumanism and Simulation Hypothesis videos that you could run a million people real time off the same power needed to light a 100 watt light bulb, the same power as human emits in heat, at room temperature if you could do your calculations at the Landauer Limit. Pushing that down to the current temperature of the Cosmic Microwave Background radiation, 100 times cooler, would let you run 100 million people on that same power, or one million people on a watt, and do that real time. But the Universe keeps getting colder, and as I mentioned those naturally occurring black holes don’t stop gaining mass and emitting real usable hawking radiation till the Universe gets colder than them. So what is the temperature of a black hole? A naturally occurring one? Well we usually say you need to be about three times more massive than our sun is for a neutron star to collapse into a black hole, or at least most natural black holes will be that massive or more so. And those black holes live more than 10^68 years, more than 10^54 times longer than the star-forming phase of the Universe. A billion-billion-billion-billion-billion-billion times longer. And there temperature is not much over a billionth of a kelvin, about 20 billionths. So when the Universe gets that cold they start aging because they finally aren’t getting energy in faster than out and when it get hair colder you can start tapping that power and you’re now getting a billion times more calculations out of every joule of energy you get then you did running at the current theoretical maximum. And it will keep getting colder and the bigger black holes won’t be available till then. But some weirder things probably happen at below 10^-18 Kelvin, like macroscopic teleportation of matter, and it is also thought that you can’t get colder than 10^-30 Kelvin, which is well below what even black holes consisting of several entire galaxies, presumably the maximum sized naturally occurring black hole, would need to reach before they started giving off more power than they received so for our example I will stop at 10^-18 Kelvin, where you can get a billion, billion times more calculations then you can squeeze out per joule now. It is more than enough to drive home the sheer enormity of these sorts of civilizations anyway. One person, digitized of course, could run on one millionth of a watt at the current minimum temperature meaning they could run at one millionth of a billionth of a billionth of a watt, or 10^-24 watts, at that 10^-18 Kelvin. Well time is an entirely subjective and relative thing at this point, so those 3 solar mass black holes still lying around are only giving you about 10^-29 Watts but that would let you run a person at 1/100,00th of real time, and a message sent a hundred thousand light years would only take a year to arrive form your perspective. Or let you run, say, a nice community of 10 million people at a trillionth of natural time, where a phone call across a hundred thousand light years would only take half a second to arrive and a full second for you to say something and hear their reply to it. Them being some other community of ten million living around another black hole. You could slow things down even more and have more people active, if you wanted and if you could keep your equipment running and practically access that ridiculously tiny power output in some fashion. I’ve no idea how you would do that but it’s not actually barred by any laws of physics to the best of my knowledge. Time might be running slow, but when your subjective time is all that matters who cares what the real time is passing at? Normally, without contemplating the Landuaer Limit, that perspective says you might as well run everybody really fast, because there’s only so much available energy in your chunk of the Universe and a lot of it is being lost to entropy every moment. So do your thinking now and get the most out of it, but in the context where we get more thinking from the same energy by waiting till things cool down, the dynamic changes completely. And even though you and your community of 10 million is only running at a trillionth of normal speed, or maybe a quadrillionth if you want an Earth sized population of ten billion, that is a subjective eternity still. Remember those 3 solar mass black holes lived more than 10^68 years. Scientific notation not being great for giving scale, even at a quadrillionth of normal speed to support 10 billion people, that’s 10^53 subjective years or 10^39 times as long as the 100 trillion year phase of the universe where there are stars, a thousand trillion-trillion-trillion times as long. I said way back in the redo of the Dyson Dilemma and Fermi Paradox Compendium, when I first decided to do this video, that we often see that period after the stars die out as the end off everything, an eternity of darkness, but in reality it would be pretty vibrant times. Most of the mass energy of the Universe will still be around when the stars die off and we’ll be reaping it billions of billions of times more efficiently, so you could have billions of billions times as many lifetimes in that dark phase after the stars than during it. And that’s what we’ve shown here. And if you have seen the Simulation Hypothesis video, contemplate that, or keep it in mind should you go watch or re-watch it. Because it not only adds massively to the sheer number of possible people involved it also adds us another motivation for doing such things. Nothing lasts forever and running super-intelligences is expensive, so near the end there could be a time where you’ve dumbed people back down to modern levels and traded your history and the matter and energy used to store it to buy more life and obscure that time is running down. I don’t want to focus on that aspect because it should just be a final tiny and somewhat depressing snippet of that very longed lived and enormous post-stellar civilization but I don’t want to bypass how that could alter our view of some of our previous topics either. Now it’s all very speculative, we may find better ways to power civilizations, that’s a long time to learn to beat entropy somehow, and it may be impossible to tap these powers sources practically to their full amount, but even the rotational energy methods we discussed earlier, if held off until those cold phases for tapping, will do pretty good. But the take away is that even as we’ve discussed before in the context of megastructures and interstellar colonization, that we are probably only the tiniest earliest fraction of humans around, the post-stellar civilizations at the end of time will overshadow even those we’ve previously discussed in sheer size and duration. They dwarf in every respect even the most extreme galaxy spanning Kardashev-3 civilizations we’ve contemplated before. Even factoring in subjective time slowing things millions or trillions of fold, the sheer number of people that can be supported this way, from the cooling of the Universe lowering the cost of calculations, simply crushes the entire stellar phase of the Universe into a tiny side note of civilization that is noteworthy only because it was early, same as those early civilizations in the Fertile Crescent remain important to us even though there are backwater towns by the tens of thousands that exceed the mighty cities of that time in numbers and totally eclipse them in effective power. These latter day civilizations in the cold universe, living off black holes and the other seeming remnants of a dead universe, turn out to be so immense in scope that they can’t be regarded as civilizations at the end of time, but rather the real civilization of which everything that came before was simply a quick prologue. And that’s Black Hole Farming, and they make for a pretty fertile farm after all. We may revisit some of the earlier stages, life around dying stars or some options for Galactic scale Megastructures in future videos. We might even take a peak at the idea of Boltzmann Brains, which can conceivably exist in defiance of entropy, but that finishes our look for today. In the meantime it’s back to the habitable planets series next week for a look at Panthallassic Planets, Worlds entirely covered in water, and what life might be like trying to evolve there or if we went to such a world to colonize it. The week after that we finally return to the Faster Than Light series to look at wormholes, where will discuss the theory, look at some of the problems with making them and how they could result in time travel causality loops, and also explore a lot of the overlooked uses of the things if they can be made to work like terraforming planets or serving as power plants or even refueling dying stars. If you want alerts when those videos come out, make sure to subscribe to the channel. If you enjoyed the video, please hit the like button and share it with others. Question and comments are always welcome, and I encourage you to read those left by others and talk to them because we get some very insightful comments on these videos form the audience. If you want to help support the channel you can find the patreon link in the video description, and in the meantime please try out some of the other video series on this channel. As always, thanks for watching, we’ll see you next time, and have a great day!
Info
Channel: Isaac Arthur
Views: 681,127
Rating: 4.8327222 out of 5
Keywords: black hole, black holes, black hole farming, singularity, accretion disk, penrose process, penrose mechanism, Blandford-Znajek Process, Fate of the Universe, End of the Universe, End of Time, degenerate matter, black dwarf star, neutron star, pulsar, Laundauer Limit, whole brain emulation, post-stellar
Id: Qam5BkXIEhQ
Channel Id: undefined
Length: 36min 5sec (2165 seconds)
Published: Thu Jul 14 2016
Reddit Comments

After subscribing to Isaac Arthur's Youtube channel a while back I learned that when you see the little red science and futurism box on a video thumbnail you click that video thumbnail.

👍︎︎ 255 👤︎︎ u/NecroSocial 📅︎︎ Sep 14 2017 🗫︎ replies

The content is amazing but on a purely superficial note, I love this guys accent and his name, Isaac Arthur, is perfect. Because Isaac Asimov and Arthur C. Clarke. It just fits

👍︎︎ 357 👤︎︎ u/SkankHunt70 📅︎︎ Sep 14 2017 🗫︎ replies

A brilliant video-series! I like how he doesn't dumb down any of the technical terms and the concepts he discusses is really fascinating. People who talk of the speech impediment, have you ever heard anyone with a thick accent speaking? Turn on the close captions and you'll get used to it super quickly

👍︎︎ 126 👤︎︎ u/Webzon 📅︎︎ Sep 14 2017 🗫︎ replies

Nice to see some Isaac Arthur up in here.

👍︎︎ 35 👤︎︎ u/superfudge 📅︎︎ Sep 14 2017 🗫︎ replies

It's Arthursday today! He comes out with a new video every Thursday and they're always good. Link

👍︎︎ 18 👤︎︎ u/postingisstupid 📅︎︎ Sep 14 2017 🗫︎ replies

This guy is the shit...l have been following him for quite a while now and his biggest strength is he doesnt dum the topic down too much like most documentaries do...either you get it or you watch it again..and again....kkkk😂

👍︎︎ 34 👤︎︎ u/Metrorepublica 📅︎︎ Sep 14 2017 🗫︎ replies

I'm of the personal belief that we may never have to resort to farming black holes, because if we are still around at that stage of the universe we will have succeeded in traveling between dimensions or at the very least manipulating entropy by that point, therefore basically either​ having no need to stay in this one or choosing our own destiny.

Edit: I would totally agree that we should adhere to our current understanding of physical law and plan accordingly. This is simply a personal thought about a possible outcome a billion years from now, not something we as a species should hang our hat on.

👍︎︎ 59 👤︎︎ u/Samusade 📅︎︎ Sep 14 2017 🗫︎ replies

Sub is r/IsaacArthur for those interested

👍︎︎ 13 👤︎︎ u/StrangelyTall 📅︎︎ Sep 14 2017 🗫︎ replies

this is youtube video, not a documentary.

👍︎︎ 9 👤︎︎ u/miraoister 📅︎︎ Sep 14 2017 🗫︎ replies
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