For the first part, please click here.
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 post and if the idea of living in a computer feels off to you it might be better to read that now or when you’re done with this post.
We used that to jump into the Doomsday Argument and Simulation Hypothesis posts 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 post 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 read 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 post, 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 post.
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
posts 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 post, 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 post, contemplate that, or keep it in mind should you go read or re-read 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 posts.
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.
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