So today’s topic is Starlifting, a way of
removing mass directly from a star, like our sun. I have talked about starlifting from time
to time in the past but never in any detailed way, so we will explore it in depth today. How you would do this and why you would do
this are our primary goals for today, though we are going to cover them backwards, by asking
why you want to do this, then discussing the various methods. I should add if you are new to this channel
that this probably is not the best episode to begin with, it is loosely tied into the
megastructures series. So while you do not need to have watched those
first, it will help, and you may want to watch them and come back. Or watch them afterwards, particularly episodes
4, 5, and 8. Before we jump into to how we gather matter
from off a star let’s talk about why you would do this. There’s basically seven reasons:
1. To get hydrogen from the star
2. To get the other elements from the star
3. To make heavier elements via Transmutation
4. To extend the lifetime of a star
5. To decrease the brightness of a star
6. To make new stars
7. To prevent a larger star from exploding Now many of those overlap of course but they
form your motivations for doing this, and it is a time and effort intensive process
so you need good motivations. I joked in the teaser for this episode last
week that it is how you destroy a star, which is true enough, but it is like destroying
a star the same way you destroy a mountain by mining it. Destruction is not your real objective. Stars are mostly made up of hydrogen, the
most abundant type of normal matter in the universe. They convert that into helium to produce energy
by nuclear fusion. In the largest stars, as their cores get depleted
of hydrogen and they begin burning helium, they can also produce heavier elements too. Now if we have working nuclear fusion, especially
fusion that can, like a star, turn normal hydrogen into helium, then stars are handy
places to find hydrogen to fuel your fusion reactors. But the sun is not the best place to mine
for hydrogen, since Jupiter has tons of it and is easier to get it from if you already
have fusion to power all your extraction efforts. Jupiter is big, but not as big as the Sun,
so the gravity is less and it is not as hard to get the hydrogen away from it. Of course it is not as big, so it does not
have nearly as much hydrogen and if you run out you have to turn to the Sun. In fact you would probably start with the
smaller gas giants like Saturn to begin with for the same reason. Saturn has less gravity, so it is less effort
getting the stuff. Now, even without fusion, hydrogen has three
very good uses. First it is incredibly plentiful, so makes
a nice source of mass when you are building things like the Shell Worlds we discussed
in Megastructures Episode 5. When you just need mass, Hydrogen is pretty
handy. Second it is actually one of the best radiation
shields you can get, it’s not only plentiful and useless for normal construction, but is
great for stopping high energy radiation. As such, it makes a nice shielding layer around
things like the rotating habitats we discussed in Megastructures episode 4. Being cheap and plentiful you can shield space
stations from collisions, radiation, and attack by having thin-walled tanks of hydrogen surrounding
your structure like armor. If you are powering that with a fusion reactor
it also makes a good place to store your fuel. Third, hydrogen is plentiful in the Universe,
but in the inner solar system it is quite uncommon, with the obvious exception of the
sun itself, and oxygen, the third most abundant substance in the Universe is the most common
substance in the inner solar system, and those two make water which is important for life. So if you want lots of water, just about all
of it is on Earth, and you will need a lot of hydrogen to make more of that. Those are the most obvious uses for hydrogen
itself, besides making new stars which we will get to in a bit. But it is easy for folks to forget that hydrogen
and helium are not the only things in the sun, and we call everything but these two
metals. A star’s metallicity is a measure of everything
else in it besides hydrogen and helium, even though very little of that is what we would
normally call metals. We actually break stars into three categories,
population 1, 2, and 3 based on how much metal they have in them. The very oldest stars, the ones still alive
from back near the beginning of things or in distant galaxies where we can see back
in time to the early universe, are population 3 stars and have virtually no metals. Newer stars have more because when old stars
explode and release metals it tends to get just as many of those in the stars as the
planets get. Population 2 stars are considered metal-poor,
and they are a bit hotter and bluer than Population 1 stars, metal rich stars, since they can
run a bit hotter without those metals interfering with fusion. Population 2 and 3 stars are not considered
great candidates for having nice rocky planets like Earth since the emerging solar system
would not have had many metals to form rocky planets from. Our sun is defined as Population 1, metal-rich,
which means it has a bit less than two percent of its mass from stuff besides hydrogen and
helium, most of which is oxygen. A bit less than two percent might not sound
like much, but it means the sun has more of these metals than the rest of the solar system
combined, since even Jupiter, which outmasses the rest of the solar system combined itself
by a large margin, only masses a thousandth of what the sun does and it is mostly hydrogen
and helium too. Meaning the sun has something like twenty
times Jupiter’s total mass, or six or seven thousand times the Earth’s mass, in these
metals. You might think denser materials would be
all packed up in the core of the Sun, but they tend to be fairly well-distributed throughout. The sun is quite convective and the contents
mix around like a bubbling soup. So, if you lift matter off the Sun you will
get plenty of these metals too. Most is oxygen, and the biggest chunk of the
remainder is carbon followed by nitrogen, and those are the three biggest consumers
of mass when you are trying to make artificial space habitats and planets. Whenever I am talking about Dyson Spheres…
which is technically almost never since I am usually talking about Dyson Swarms instead… I get asked by some where you would come up
with all the mass to build one of the spheres or swarms. Now as I have mentioned in the past there
is more than enough material in the Planet Mercury alone to build a small swarm of thin
power collectors around the sun, but if you need a lot of mass so you can build more substantial
structures the Sun is a great source in and of itself. If you extracted all those elements besides
hydrogen and helium from the Sun you would have a couple thousand times more of them
then you would from disassembling all the rocky inner planets and asteroids combined. If we were envisioning trying to build a classic
Dyson shell around the sun out at Earth’s distance this would per a surface of around
3 x 10^23 square meters. If you only use Earth’s mass this would
only give you about 20 kilograms per square meter, again more than enough for solar panels
around the sun but not much to live on. Yank all that matter out of the sun and this
becomes a much more robust figure of about 100 tons a square meter. Which is definitely a comfortable amount of
material to be building human habitats out of. You have everything you need to make rock
and water and air out of. Of course if that is not enough we still have
the option of transmutation. Heavier elements are made by nuclear fusion,
hydrogen turns into helium that turns into carbon, oxygen, and so on. So hypothetically you can turn hydrogen into,
say, iron, with some steps in between, and actually gain energy from doing this. We have not yet mastered the easiest type
of fusion, which is hydrogen’s isotopes deuterium and tritium. But if we managed to get this unlocked we
might be able to do plain, vanilla hydrogen fusion too, and learn to turn helium into
carbon, which is even harder, and possibly all the higher ones. It is all about getting a high enough temperature
and pressure in your reactor, and if you can do that you can not only make those higher
elements in a reactor, but get a net positive amount of energy out of it. Two birds with one stone. This is obviously preferred and if you can
do it, since you can not only yank hydrogen and helium off your sun and turn them into
whatever you want but also gain power from it. But right now we can make these thing by slamming
lighter nuclei together in a super-collider. That costs power, quite a lot of it, but if
you need heavier matter because you don’t have enough of it, and most of your Dyson
Swarm consists of power collectors, not artificial habitats, you can use all that extra power
from the sun to scoop hydrogen and helium up from the sun and run it around a giant
supercollider also powered by the sun. As you do this you will also be decreasing
the mass of the Sun and so also decreasing its power output, but that is actually a good
thing since if the sun is getting dimmer while you are making more matter to build stuff
around it you will also need less and less matter to absorb all that light, since there
is less of it, and you just keep going until you reach a happy medium. You make your star lighter and lighter and
dimmer and dimmer making material to encompass that star, until you have what you need to
encompass that newer dimmer star that doesn’t need as much mass to encompass it anymore. So it really doesn’t matter how inefficient
this process is, but again the fusion of matter into heavier elements produces energy so there’s
a very good chance you could run this operation at a profit rather than having to dump tons
of energy down the drain for transmutation, but if that’s your only option it is still
doable. Of course, that is not the only reason to
decrease a star’s mass. Stars get dimmer as they lose mass, quite
a lot dimmer too. A star twice as massive as our sun is not
twice as bright, they are about 16 times brighter, while one half as massive as us is about one-sixteenth
as bright. Because of this, even though bigger stars
have more fuel, they do not live nearly as long, less than you would think since they
tend to explode long before they use up all their hydrogen. Smaller stars use a lot more of their hydrogen
and they use it a lot slower, so they live a lot longer. Our sun is about halfway through its life
of about ten billion years, ones twice as big live a bit under 2 billion years while
one half our size would live more like 60 billion years. So we could extend our Sun’s lifetime by
removing some of its mass, more than you might expect since by decreasing that mass we let
it stir around its contents more to make it keep going longer with less helium in the
core killing the current hydrogen fusion process. Indeed you could constantly starlift, removing
the helium and other elements and dumping the hydrogen back down, and even adding more
hydrogen from other sources to potentially extend that star’s life indefinitely so
long as you have hydrogen to keep adding. And again, smaller stars churn their contents
up more so decreasing a star’s mass makes it easier to remove the helium which could
be thought of as the poison or toxin that kills stars. Also again, smaller star, dimmer star, less
material needed to make use of the light it does put off. Yank just 10% of our sun’s mass off and
it would be about two-thirds as bright as now, needing only two-thirds the material
to construct a Dyson swarm, and you will have about 30,000 times the mass of Earth in matter
to play with. Of course what you do with all that removed
hydrogen and helium is another story. So is capturing it when it comes off the sun
which we will talk about when we discuss how you actually do starlifting in a couple minutes. You have the option of making another smaller
sun out of it, and again smaller suns are a lot better at converting hydrogen to helium
without exploding before they finish. It is generally thought that stars under about
a quarter of the mass of our own sun, smaller red dwarf stars, do not even become red giants
as other stars do near the end of their life but just turn into blue dwarf stars instead. Not expanding just getting hotter then turning
into white dwarf stars at the end. We cannot be sure since no star in the universe
of that mass has been around long enough to do this. But these are the type of red dwarf stars
that are thought to be able to live over a trillion years. The ones a bit more massive live a lot longer
than our sun but still go red giant at some point before they go through all their hydrogen,
so they live significantly shorter lives than these. Most stars in the Universe are Red Dwarf stars
too, and we are talking about maybe turning our own sun into one by starlifting, so let
me remind everyone that the color of stars is a bit of a misnomer, they all give off
white light. The spectrum is a bit different but even the
dimmest and coldest red dwarf would give a light similar to an incandescent light bulb. I have heard people object to the idea of
settling worlds around red dwarf stars because they would not want live under red light,
besides this being, presumably, much better than not being alive at all, I mean, I would
rather live in the tundra than not at all, it’s also wrong since the light will be
about the same as what you are used to. If you really wanted that hotter, whiter light
you could just make blue dwarf stars from the outset by using a mixture of hydrogen
and helium anyway, if you are in the star making game. Gives you something to do with all that helium,
I suppose. But speaking of dying stars and red giants
brings up our last use of starlifting, which is preventing the bigger ones from exploding. Now I mentioned back in the Shkadov Thrusters
episode, which dealt moving stars, that it easier to move bigger ones than smaller ones. The result of which is that if you have a
giant star getting ready to go supernova it is easier to move it away from your own solar
system than to move your solar system. A better option anyway, since you probably
colonized many solar systems in that area so it is better to give the boot to the single
big problem child in your neighborhood than to move all the other colonized solar systems. But Starlifting offers us an alternative to
that. You get in there and instead of using that
star’s light to push it away, you use that light to power starlifting and strip mass
off the star before it can explode violently. And while Supernovae are our main source of
metals, that is not an efficient process anyway so you would probably be better off using
the supercollider approach even if you have not got some easier method of transmutation
available. Okay, so lastly, how do we actually do this? As I mentioned there are multiple methods,
but there are three key ones that usually get discussed and I will limit us to those. With the exception of mentioning the most
simple and obvious, which is just flying down there and scooping the matter up and flying
away. They did that in the TV show Stargate Universe
and it was probably my favorite scene in the sadly short-lived spin-off my favorite science
fiction franchise. This is not going to be a practical approach
unless you have all sorts of awesome technology we do not have. It is also generally called Sun Scooping,
not Star Lifting, though it is both. When you start talking about harvesting stars
for their matter, people tend to assume only very high technology civilizations could do
such things. Some of us call that Clarketech, as a hat
tip to Arthur C. Clarke and his quote about any sufficiently advanced technology being
indistinguishable from magic. The methods we will be talking about are not
high-tech at all, much like Dyson Swarms, while people think of them as super-high-tech,
as Clarketech, they can be done with just raw brute force. You do not need much technology. All three of these methods we are about to
discuss were thought up, to the best of my knowledge, by David Criswell who also is assumed
to have coined the term Starlifting. They are:
1. Thermal Driven Outflow
2. Centrifugal Acceleration, and
3. The Huff and Puff Method
I always get a kick out of the name for the last one. Okay, the first, Thermal Driven Outflow, which
I will just call TDO Starlifting henceforth or TDO, basically works by heating up bits
of a star’s atmosphere. You can do this by beaming down microwaves
powered by solar panels, or even just reflecting light back down focused on a spot with big
mirrors. Those mirrors could hover over the same spot
instead of orbiting, using the Statite method we have discussed in the past. This would kick up an eruption much like a
solar flare, feeding more solar wind, you would then have a giant ring around the sun
sucking up sunlight and generating a big ring of current as well as a huge toroidal magnetic
field. This would tend to pump this matter up or
down out the poles of the sun, which is handy since we live around the equator. Incidentally, you could do this on the Sun
right now to collect the normal solar wind, but our Sun’s solar wind does not give off
that much matter. Bigger stars give off tons that way, but for
ours you need to be blasting spots to cause eruptions and increase the solar wind. Now the capture method for this stuff as it
heads up from the pole is to use giant magnetic rocket nozzles. Magnetic nozzles are a concept that’s been
discussed for use in the VASIMR thruster which we discussed along with some other propulsion
methods a couple episodes back. This lets you use magnetic fields to direct
plasma rather than having it flow through a classic metal nozzle which would get kind
of hot. It also cools the plasma slightly, making
it much easier to collect. Two quick notes: First the ring around the
sun does not have to be a solid object, it can just be a bunch of orbital stations, they
can just shoot streams of charged ions between each other to make that ring of current, each
station is a particle accelerator presumably powered by sunlight. But you could use a solid one and it would
not fly apart or anything, it is not a Niven-style Ringworld under huge centrifugal force, though
we discussed making giant stationary rings back in the first episode of the megastructures
series if you want one. A solid one is maybe more useful if you want
to have a massive collection of supercolliders for transmutation of elements. Second, the nozzles are probably way too dense
to work as Statites, unlike mirrors which can just hover over the sun bouncing light
back down, and they need to stay over the poles, so if you are wondering how they would,
just remember they are called giant magnetic rocket nozzles for a reason. They can keep themselves from falling down
by sucking in all that matter flying off the star at high speeds. Giant Plasma Thrusters. Notice by the way that TDO Starlifting is
not particularly high tech, and I want to emphasize that. Okay, method 2, Centrifugal Acceleration,
or CA starlfiitng. This is a lot like TDO Starlifitng but you
put your ring around the poles instead, and your nozzles around the equator. You then rotate your ring a lot faster than
that star rotates, and rotate it around the star’s poles and it starts flinging matter
outward. This is much harder, since you have to keep
pushing on that ring to keep it spinning, but as I understand it this is supposed to
create a much faster outflow of matter, albeit sprayed all over the place, so I think this
would be the sort of thing you would do if your main goal was not harvesting the star
for matter but just lightening it in a hurry. TDO is better, or at least simpler. Okay, Method 3, Huff and Puff, which I guess
we would call H&P Starlifting. Huff and Puff sounds cooler though, but the
actual effect is more like a bellows. Here your ring of particle accelerators are
not staying up by orbiting the sun but magnetically floating over it, akin to the electrodynamic
tethering method we discussed in the Spaceship Propulsion Compendium, but it is the ring
current they are generating that is holding them up. You then shut the ring current off and let
the stations begin to fall. Once they pick up a lot of speed you snap
the ring current back on and they begin flying back up away from the sun, rinse and repeat. Doing this generates a squeezing action on
the sun pumping the sun’s atmosphere up through the poles, again to be caught by the
magnetic rocket nozzles. If you are only using one ring to do this
you would get that beating pulse or bellows effect on the polar matter stream but you
could have several rings doing this at once in well-timed pumping action for a bigger
and more steady outflow of matter. Personally this is the one I like the most,
partially for the name, and it should be faster than TDO which is a much more passive process. Okay, some notes on lifting matter: Removing
matter from the sun cost about 200 billion joules per kilogram, and that’s the minimum
if you are doing it with 100% efficiency. That’s a thousand times what is to get off
Earth, so do not think this is an easy process. That said, while it costs a couple hundred
billion joules of energy to yank a kilogram of matter off the sun, fusing a kilogram of
hydrogen into helium produces gets you more than thousand times that much energy so even
if you are not doing it too efficiently the sun provides a lot more power from fusion
then is needed to take the sun apart. If you used the sun’s entire energy output
at 100% lifting efficiency you could remove about an Earth’s worth of mass this way
every century, and take apart the sun in about 30 million years. Realistically even getting 10% efficiency
would be very impressive, and you would not be using all the sun’s light for this, so
think of this as a very slow process. Not that the more optimistic 30 million years
is exactly fast. Giant stars have more binding energy but are
a lot less dense, they’re much bigger than their mass would indicate, especially red
giants which are often as big as a Dyson Sphere but only as massive as our own sun. They are also way brighter, giving you way
more power to work with, so you can pull one apart a lot faster. I would not want to go racing off trying to
prevent a supergiant star that just transitioned into a red supergiant and trying to suck the
mass off it before it went supernova, they usually only spend one or two million years
in that state, but you probably could do it. Needless to say getting there when they are
younger is a smarter idea. But that is one of the reasons why I tell
people that Interstellar civilizations do not need to worry much about a supernova wiping
them out. A Supernova is not particularly big threat
to a K2 civilization let alone a bigger one, and anyone engaging in Starlifitng is almost
by definition a K2 Civilization or very close to it. Speaking of which, in two weeks we will be
discussing a lot of the other cool things a K2 civilization, or Kardashev 2 civilization,
can do in an episode on the Kardashev Scale. We have talked about that before but always
in passing and usually just one cool thing they can do. That topic got picked by the Facebook group,
Science and Futurism with Isaac Arthur, and we always have a poll going on over there
to pick topics for the channel so head on over and join and vote. This week’s video was selected as a topic
by our Patreon group, the winner being Bill Mains, and I wanted to thank him for selecting
this topic and helping me plan out the material. We also have our third and final topic winner,
Neo Navras, who has selected Stars as our topic which we will do sometime in November. We still need to flush out what will be covered
but I will be demystifying a lot of the astronomical terms and also discussing a lot of the weird
hypothetical stars like Quark Stars or Dark Matter Stars. These Patreon picks have been a lot of fun
to do so I will probably continue this with modification in the future. I’ll put those details out when I decide
the best way to do that. Next week’s topic however is CryptoCurrency
and BlockChain, and we will be looking at these concepts and contemplating how they
might be useful in related areas or for things like interstellar commerce, when it might
take years to confirm someone’s bank account balance if they are visiting your solar system. So again, next week is Cryptocurrency, don’t
forget to subscribe to the channel if you want alerts when that and future videos come
out, and in the meantime you can try out some of the other episodes on the channel. If you enjoyed this episode don’t forget
to like it and share it with others. Until next week, thanks for Watching and have
a Great Day!
Just so you don't have to watch the whole video the basic concept of starlifting is to use a similar structure to a dyson sphere to lift heavy material out of a stars core that could be used for manufacturing. You could get a ridiculous amount this way and it would be great for the end game
I literally found this game because from SFIA people were making memes of it. Issac is bae and its wild to see a game that allows me to actually build something a futuristic as a swarm/shell.
Completely consuming planets would be neat as well, maybe through some tower constructs which mine the planet and port the material up to supply ships
Ah, I see you're a man of culture as well
Isaac Arthur and SFIA is what got me really into Hard Sci-Fi, and I am definitely hoping the devs can take some notes from some of the concepts he talks about.